Publications by authors named "Carl M Maresh"

203 Publications

Acute Effects of High-intensity Resistance Exercise on Cognitive Function.

J Sports Sci Med 2021 Sep 3;20(3):391-397. Epub 2021 May 3.

Department of Psychology, The Ohio State University, Columbus, OH, USA.

The purpose of the present study was to examine the influence of an acute bout of high-intensity resistance exercise on measures of cognitive function. Ten men (Mean ± SD: age = 24.4 ± 3.2 yrs; body mass = 85.7 ± 11.8 kg; height = 1.78 ± 0.08 m; 1 repetition maximum (1RM) = 139.0 ± 24.1 kg) gave informed consent and performed a high-intensity 6 sets of 10 repetitions of barbell back squat exercise at 80% 1RM with 2 minutes rest between sets. The Automated Neuropsychological Assessment Metrics (ANAM) was completed to assess various cognitive domains during the familiarization period, immediately before, and immediately after the high-intensity resistance exercise bout. The repeated measures ANOVAs for throughput scores (r·m) demonstrated significant mean differences for the Mathematical Processing task (MTH; < 0.001, η = 0.625) where pairwise comparisons demonstrated that the post-fatigue throughput (32.0 ± 8.8 r·m) was significantly greater than the pre-fatigue (23.8 ± 7.4 r·m, = 0.003, = 1.01) and the familiarization throughput (26.4 ± 5.3 r·m, = 0.024, = 0.77). The Coded Substitution-Delay task also demonstrated significant mean differences (CDD; = 0.027, η = 0.394) with pairwise comparisons demonstrating that the post-fatigue throughput (49.3 ± 14.4 r·m) was significantly less than the pre-fatigue throughput (63.2 ± 9.6 r·m, = 0.011, = 1.14). The repeated measures ANOVAs for reaction time (ms) demonstrated significant mean differences for MTH ( < 0.001, η = 0.624) where pairwise comparisons demonstrated that the post-fatigue reaction time (1885.2 ± 582.8 ms) was significantly less than the pre-fatigue (2518.2 ± 884.8 ms, = 0.005, = 0.85) and familiarization (2253.7 ± 567.6 ms, = 0.009, = 0.64) reaction times. The Go/No-Go task demonstrated significant mean differences (GNG; = 0.031, η = 0.320) with pairwise comparisons demonstrating that the post-fatigue (285.9 ± 16.3 ms) was significantly less than the pre-fatigue (298.5 ± 12.1 ms, = 0.006, = 0.88) reaction times. High-intensity resistance exercise may elicit domain-specific influences on cognitive function, characterized by the facilitation of simple cognitive tasks and impairments of complex cognitive tasks.
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http://dx.doi.org/10.52082/jssm.2021.391DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8256515PMC
September 2021

Hormonal stress responses of growth hormone and insulin-like growth factor-I in highly resistance trained women and men.

Growth Horm IGF Res 2021 Aug 6;59:101407. Epub 2021 Jun 6.

Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, USA.

The purpose of this study was to examine the responses of growth hormone (GH) and insulin-like growth factor-I (IGFI) to intense heavy resistance exercise in highly trained men and women to determine what sex-dependent responses may exist. Subjects were highly resistance trained men (N = 8, Mean ± SD; age, yrs., 21 ± 1, height, cm, 175.3 ± 6.7, body mass, kg, 87.0 ± 18.5, % body fat, 15.2 ± 5.4, squat X body mass, 2.1 ± 0.4; and women (N = 7; Mean ± SD, age, yrs. 24 ± 5, height, cm 164.6 ± 6.7, body mass, kg 76.4 ± 8.8, % body fat, 26.9 ± 5.3, squat X body mass, 1.7 ± 0.6). An acute resistance exercise test protocol (ARET) consisted of 6 sets of 10 repetitions at 80% of the 1 RM with 2 min rest between sets was used as the stressor. Blood samples were obtained pre-exercise, after 3 sets, and then immediately after exercise (IP), 5, 15, 30, and 70 min post-exercise for determination of blood lactate (HLa), and plasma glucose, insulin, cortisol, and GH. Determination of plasma concentrations of IGFI, IGF binding proteins 1, 2, and 3 along with molecular weight isoform factions were determined at pre, IP and 70 min. GH significantly (P ≤ 0.05) increased at all time points with resting concentrations significantly higher in women. Significant increases were observed for HLa, glucose, insulin, and cortisol with exercise and into recovery with no sex-dependent observations. Women showed IGF-I values that were higher than men at all times points with both seeing exercise increases. IGFBP-1 and 2 showed increase with exercise with no sex-dependent differences. IGFBP-3 concentrations were higher in women at all-time points with no exercise induced changes. Both women and men saw an exercise induced increase with significantly higher values in GH in only the mid-range (30-60 kD) isoform.  Only women saw an exercise induced increase with significantly higher values for IGF fractions only in the mid-range (30-60 kD) isoform, which were significantly greater than the men at the IP and 70 min post-exercise time points. In conclusion, the salient findings of this investigation were that in highly resistance trained men and women, sexual dimorphisms exist but appear different from our prior work in untrained men and women and appear to support a sexual dimorphism related to compensatory aspects in women for anabolic mediating mechanisms in cellular interactions.
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http://dx.doi.org/10.1016/j.ghir.2021.101407DOI Listing
August 2021

Short term heat acclimation reduces heat strain during a first, but not second, consecutive exercise-heat exposure.

J Sci Med Sport 2021 Apr 6. Epub 2021 Apr 6.

Korey Stringer Institute, Department of Kinesiology, University of Connecticut, USA.

Objectives: Determine whether five days of heat acclimation reduces cardiovascular and thermoregulatory strain during consecutive exercise-heat exposures on the sixth day in the heat.

Design: Pair-matched randomized control trial.

Methods: Twenty-four males completed two, 120min exercise sessions (Session 1, Session 2) in a single day before (Day 1) and after (Day 6) four additional days of exercise in either hot (HOT: 40°C, 40% relative humidity, n=16) or temperate (CON: 23°C, 25% relative humidity, n=8) environments. A mixed-methods heat acclimation approach was implemented. Day 2 consisted of 120min of moderate-high intensity treadmill exercise. Days 3-5 consisted of 90min of moderate-high intensity exercise, with HOT completing this in a hyperthermia clamped manner at rectal temperature ≥38.5°C, and CON<38.5°C.

Results: Session 1 end of exercise rectal temperature and heart rate were lower on Day 6 compared to Day 1 for HOT (p=0.012, p=0.003) but not CON (p=0.152, p=0.437). Session 2 end of exercise rectal temperature was not different between days for HOT (p=0.104) or CON (p=0.275). Session 2 end of exercise heart rate was lower on Day 6 compared to Day 1 for HOT (p=0.004) and CON (p=0.039). Session 1 sweat sensitivity was greater on Day 6 compared to Day 1 for HOT (p=0.039) but not CON (p=0.257). Sweat rate was unchanged for HOT and CON between days during Session 1 (p=0.184, p=0.962) and Session 2 (p=0.051, p=0.793), respectively.

Conclusions: Five days of heat acclimation reduced cardiovascular strain but not thermoregulatory strain during the second, consecutive exercise-heat exposure. CLINICALTRIALS.

Gov Identifier: NCT04053465.
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http://dx.doi.org/10.1016/j.jsams.2021.03.020DOI Listing
April 2021

Differences in brain structure and theta burst stimulation-induced plasticity implicate the corticomotor system in loss of function after musculoskeletal injury.

J Neurophysiol 2021 04 17;125(4):1006-1021. Epub 2021 Feb 17.

Department of Human Sciences, The Ohio State University, Columbus, Ohio.

Traumatic musculoskeletal injury (MSI) may involve changes in corticomotor structure and function, but direct evidence is needed. To determine the corticomotor basis of MSI, we examined interactions among skeletomotor function, corticospinal excitability, corticomotor structure (cortical thickness and white matter microstructure), and intermittent theta burst stimulation (iTBS)-induced plasticity. Nine women with unilateral anterior cruciate ligament rupture (ACL) 3.2 ± 1.1 yr prior to the study and 11 matched controls (CON) completed an MRI session followed by an offline plasticity-probing protocol using a randomized, sham-controlled, double-blind, cross-over study design. iTBS was applied to the injured (ACL) or nondominant (CON) motor cortex leg representation (M1) with plasticity assessed based on changes in skeletomotor function and corticospinal excitability compared with sham iTBS. The results showed persistent loss of function in the injured quadriceps, compensatory adaptations in the uninjured quadriceps and both hamstrings, and injury-specific increases in corticospinal excitability. Injury was associated with lateralized reductions in paracentral lobule thickness, greater centrality of nonleg corticomotor regions, and increased primary somatosensory cortex leg area inefficiency and eccentricity. Individual responses to iTBS were consistent with the principles of homeostatic metaplasticity; corresponded to injury-related differences in skeletomotor function, corticospinal excitability, and corticomotor structure; and suggested that corticomotor adaptations involve both hemispheres. Moreover, iTBS normalized skeletomotor function and corticospinal excitability in ACL. The results of this investigation directly confirm corticomotor involvement in chronic loss of function after traumatic MSI, emphasize the sensitivity of the corticomotor system to skeletomotor events and behaviors, and raise the possibility that brain-targeted therapies could improve recovery. Traumatic musculoskeletal injuries may involve adaptive changes in the brain that contribute to loss of function. Our combination of neuroimaging and theta burst transcranial magnetic stimulation (iTBS) revealed distinct patterns of iTBS-induced plasticity that normalized differences in muscle and brain function evident years after unilateral knee ligament rupture. Individual responses to iTBS corresponded to injury-specific differences in brain structure and physiological activity, depended on skeletomotor deficit severity, and suggested that corticomotor adaptations involve both hemispheres.
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http://dx.doi.org/10.1152/jn.00689.2020DOI Listing
April 2021

Effects of cold water immersion on circulating inflammatory markers at the Kona Ironman World Championship.

Appl Physiol Nutr Metab 2021 Jul 28;46(7):719-726. Epub 2021 Jan 28.

Department of Kinesiology, Human Performance Laboratory, University of Connecticut, Storrs, CT, USA.

Cold water immersion (CWI) purportedly reduces inflammation and improves muscle recovery after exercise, yet its effectiveness in specific contexts (ultraendurance) remains unclear. Thus, our aim was to study hematological profiles, systemic inflammation, and muscle damage responses to a specific post-race CWI (vs. control) during recovery after the Ironman World Championship, a culmination of ∼100 000 athletes competing in global qualifying Ironman events each year. Twenty-nine competitors were randomized into either a CWI or control (CON) group. Physiological parameters and blood samples were taken at pre-race, after intervention (POST), and 24 (+1DAY) and 48 hours (+2DAY) following the race. Muscle damage markers (plasma myoglobin, serum creatine kinase) were elevated at POST, +1DAY, and +2DAY, while inflammatory cytokines interleukin (IL)-6, IL-8, and IL-10 and total leukocyte counts were increased only at POST. CWI had no effect on these markers. Numbers of the most abundant circulating cell type, neutrophils, were elevated at POST more so in CWI ( < 0.05, vs. CON). Despite that neutrophil counts may be a sensitive marker to detect subtle effects, CWI does not affect recovery markers 24- and 48-hours post-race (vs. CON). Overall, we determined that our short CWI protocol was not sufficient to improve recovery. Ironman World Championship event increased circulating muscle damage markers, inflammatory markers, and hematological parameters, including circulating immune cell sub-populations that recover 24-48 hours after the race. 12-min CWI post-ultraendurance event affects the absolute numbers of neutrophils acutely, post-race (vs. CON), but does not impact recovery 24- and 48-hours post-race.
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http://dx.doi.org/10.1139/apnm-2020-0602DOI Listing
July 2021

Body Composition in Elite Strongman Competitors.

J Strength Cond Res 2020 Dec;34(12):3326-3330

Division of Sports Medicine, Department of Orthopedics, Miller School of Medicine, University of Miami Sports Medicine Institute, Coral Gables, Florida.

Kraemer, WJ, Caldwell, LK, Post, EM, DuPont, WH, Martini, ER, Ratamess, NA, Szivak, TK, Shurley, JP, Beeler, MK, Volek, JS, Maresh, CM, Todd, JS, Walrod, BJ, Hyde, PN, Fairman, C, and Best, TM. Body composition in elite strongman competitors. J Strength Cond Res 34(12): 3326-3330, 2020-The purpose of this descriptive investigation was to characterize a group of elite strongman competitors to document the body composition of this unique population of strength athletes. Data were collected from eligible competitors as part of a health screening program conducted over 5 consecutive years. Imaging was acquired using dual-energy x-ray absorptiometry (DXA), providing total body measures of fat mass, lean mass, and bone mineral content (BMC). Year to year, testing groups showed a homogenous grouping of anthropometric, body composition, and bone density metrics. Composite averages were calculated to provide an anthropometric profile of the elite strongman competitor (N = 18; mean ± SD): age, 33.0 ± 5.2 years; body height, 187.4 ± 7.1 cm; body mass, 152.9 ± 19.3 kg; body mass index, 43.5 ± 4.8 kg·m; fat mass, 30.9 ± 11.1 kg; lean mass, 118.0 ± 11.7 kg, body fat, 18.7 ± 6.2%, total BMC, 5.23 ± 0.41 kg, and bone mineral density, 1.78 ± 0.14 g·cm. These data demonstrate that elite strongman competitors are among the largest human male athletes, and in some cases, they are at the extreme limits reported for body size and structure. Elite strongman competitors undergo a high degree of mechanical stress, providing further insight into the potent role of physical training in mediating structural remodeling even into adulthood. Such data provide a glimpse into a unique group of competitive athletes pushing the limits not only of human performance but also of human physiology.
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http://dx.doi.org/10.1519/JSC.0000000000003763DOI Listing
December 2020

Recovery using "float" from high intensity stress on growth hormone-like molecules in resistance trained men.

Growth Horm IGF Res 2020 12 25;55:101355. Epub 2020 Sep 25.

Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA 16802, United States of America.

Objective: The purpose of this study was to examine the influence of a novel "floatation-restricted environmental stimulation therapy" (floatation-REST) on growth hormone responses to an intense resistance exercise stress.

Design: Nine resistance trained men (age: 23.4 ± 2.5 yrs.; height: 175.3 ± 5.4 cm; body mass: 85.3 ± 7.9 kg) completed a balanced, crossover-controlled study design with two identical exercise trials, differing only in post-exercise recovery intervention (i.e., control or floatation-REST). A two-week washout period was used between experimental conditions. Plasma lactate was measured pre-exercise, immediately post-exercise and after the 1 h. recovery interventions. Plasma iGH was measured pre-exercise, immediately-post exercise, and after the recovery intervention, as well as 24 h and 48 h after the exercise test. The bGH-L was measured only at pre-exercise and following each recovery intervention.

Results: For both experimental conditions, a significant (P ≤ 0.05) increase in lactate concentrations were observed immediately post-exercise (~14 mmol • L-1) and remained slightly elevated after the recovery condition. The same pattern of responses was observed for iGH with no differences from resting values at 24 and 48 h of recovery. The bGH-L showed no exercise-induced changes following recovery with either treatment condition, however concentration values were dramatically lower than ever reported.

Conclusion: The use of floatation-REST therapy immediately following intense resistance exercise does not appear to influence anterior pituitary function in highly resistance trained men. However, the lower values of bGH suggest dramatically different molecular processing mechanisms at work in this highly trained population.
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http://dx.doi.org/10.1016/j.ghir.2020.101355DOI Listing
December 2020

Resistance Training and Milk-Substitution Enhance Body Composition and Bone Health in Adolescent Girls.

J Am Coll Nutr 2021 Mar-Apr;40(3):193-210. Epub 2020 Jun 10.

Department of Human Sciences, The Ohio State University, Columbus, Ohio, USA.

Increased soft-drink consumption has contributed to poor calcium intake with 90% of adolescent girls consuming less than the RDA for calcium. The purpose of this investigation was to determine the independent and additive effects of two interventions (milk and resistance training) on nutrient adequacy, body composition, and bone health in adolescent girls. The experimental design consisted of four experimental groups of adolescent girls 14-17 years of age: (1) Milk + resistance training [MRT];  = 15; (2) Resistance training only [RT];  = 15; (3) Milk only [M]  = 20; (4) Control [C]  = 16. A few significant differences were observed at baseline between the groups for subject characteristics. Testing was performed pre and post-12 week training period for all groups. Milk was provided (3, 8 oz servings) for both the MRT and the M groups. The MRT group and the RT groups performed a supervised periodized resistance training program consisting of supervised one-hour exercise sessions 3 d/wk (M, W, F) for 12 wk. Baseline dietary data was collected utilizing the NUT-P-FFQ and/or a 120 item FFQ developed by the Fred Hutchinson Cancer Research Center (Seattle, Washington). Body composition was measured in the morning after an overnight fast using dual-energy X-ray absorptiometry (DXA) with a total body scanner (Prodigy, Lunar Corporation, Madison, WI). A whole body scan for bone density and lumbar spine scans were performed on all subjects. Maximal strength of the upper and lower body was assessed via a one-repetition maximum (1-RM) squat and bench press exercise protocols. Significance was set at  ≤ 0.05. Significant differences in nutrient intakes between groups generally reflected the nutrient composition of milk with greater intakes of protein and improved nutrient adequacy for several B vitamins, vitamin A, vitamin D, calcium, magnesium, phosphorus, potassium, and zinc. Mean calcium intake was 758 and 1581 mg/d, in the non-milk and milk groups, respectively, with 100% of girls in the milk groups consuming > RDA of 1300 mg/d. There were no effects of milk on body composition or muscle performance, but resistance training had a main effect and significantly increased body mass, lean body mass, muscle strength, and muscle endurance. There was a main effect of milk and resistance training on several measures of bone mineral density (BMD). Changes in whole body BMD in the M, RT, MRT, and CON were 0.45, 0.52, 1.32, and -0.19%, respectively ( < 0.01). Over the course of 12 weeks the effects of 1300 mg/d of calcium in the form of fluid milk combined with a heavy resistance training program resulted in the additive effects of greater nutrient adequacy and BMD in adolescent girls. While further studies are needed, combining increased milk consumption with resistance training appears to optimize bone health in adolescent girls.
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http://dx.doi.org/10.1080/07315724.2020.1770636DOI Listing
June 2020

A Pre-Workout Supplement of Ketone Salts, Caffeine, and Amino Acids Improves High-Intensity Exercise Performance in Keto-Naïve and Keto-Adapted Individuals.

J Am Coll Nutr 2020 May-Jun;39(4):290-300. Epub 2020 Apr 24.

Department of Human Sciences, The Ohio State University, Columbus, Ohio, USA.

Acute ingestion of ketone supplements alters metabolism and potentially exercise performance. No studies to date have evaluated the impact of co-ingestion of ketone salts with caffeine and amino acids on high intensity exercise performance, and no data exists in Keto-Adapted individuals. We tested the performance and metabolic effects of a pre-workout supplement containing beta-hydroxybutyrate (BHB) salts, caffeine, and amino acids (KCA) in recreationally-active adults habitually consuming a mixed diet (Keto-Naïve; n = 12) or a ketogenic diet (Keto-Adapted; n = 12). In a randomized and balanced manner, subjects consumed either the KCA consisting of ∼7 g BHB (72% R-BHB and 28% S-BHB) with ∼100 mg of caffeine, and amino acids (leucine and taurine) or Water (control condition) 15 minutes prior to performing a staged cycle ergometer time to exhaustion test followed immediately by a 30 second Wingate test. Circulating total BHB concentrations increased rapidly after KCA ingestion in KN (154 to 732 μM) and KA (848 to 1,973 μM) subjects and stayed elevated throughout recovery in both groups. Plasma S-BHB increased >20-fold 15 minutes after KCA ingestion in both groups and remained elevated throughout recovery. Compared to Water, KCA ingestion increased time to exhaustion 8.3% in Keto-Naïve and 9.8% in Keto-Adapted subjects (P < 0.001). There was no difference in power output during the Wingate test between trials. Peak lactate immediately after exercise was higher after KCA (∼14.9 vs 12.7 mM). These results indicate that pre-exercise ingestion of a moderate dose of R- and S-BHB salts combined with caffeine, leucine and taurine improves high-intensity exercise performance to a similar extent in both Keto-Adapted and Keto-Naïve individuals.
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http://dx.doi.org/10.1080/07315724.2020.1752846DOI Listing
July 2021

Acute Kidney Injury Biomarker Responses to Short-Term Heat Acclimation.

Int J Environ Res Public Health 2020 02 19;17(4). Epub 2020 Feb 19.

Korey Stringer Institute, Department of Kinesiology, University of Connecticut, Storrs, CT 06269, USA.

The combination of hyperthermia, dehydration, and strenuous exercise can result in severe reductions in kidney function, potentially leading to acute kidney injury (AKI). We sought to determine whether six days of heat acclimation (HA) mitigates the rise in clinical biomarkers of AKI during strenuous exercise in the heat. Twenty men completed two consecutive 2 h bouts of high-intensity exercise in either hot ( = 12, 40 °C, 40% relative humidity) or mild ( = 8, 24 °C, 21% relative humidity) environments before (PreHA) and after (PostHA) 4 days of 90-120 min of exercise per day in a hot or mild environment. Increased clinical biomarkers of AKI (CLINICAL) was defined as a serum creatinine increase ≥0.3 mg·dL or estimated glomerular filtration rate (eGFR) reduction >25%. Creatinine similarly increased in the hot environment PreHA (0.35 ± 0.23 mg·dL) and PostHA (0.39 ± 0.20 mg·dL), with greater increases than the mild environment at both time points (0.11 ± 0.07 mg·dL, 0.08 ± 0.06 mg·dL, ≤ 0.001), respectively. CLINICAL occurred in the hot environment PreHA ( = 9, 75%), with fewer participants with CLINICAL PostHA ( = 7, 58%, = 0.007), and no participants in the mild environment with CLINICAL at either time point. Percent change in plasma volume was predictive of changes in serum creatinine PostHA and percent changes in eGFR both PreHA and PostHA. HA did not mitigate reductions in eGFR nor increases in serum creatinine during high-intensity exercise in the heat, although the number of participants with CLINICAL was reduced PostHA.
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http://dx.doi.org/10.3390/ijerph17041325DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7068478PMC
February 2020

Exacerbated heat strain during consecutive days of repeated exercise sessions in heat.

J Sci Med Sport 2019 Oct 18;22(10):1084-1089. Epub 2019 Jun 18.

Korey Stringer Institute, Department of Kinesiology, University of Connecticut, United States.

Objectives: An exercise session in a hot environment may increase thermal strain during subsequent exercise sessions on the same and consecutive days. Therefore, this study was conducted to determine lasting physiological strain from moderate-high intensity, intermittent exercise in heat on subsequent exercise.

Design: Repeated measures laboratory study.

Methods: Seventeen healthy, recreationally active men (age: 22±3 y, maximal oxygen consumption: 54.6±5.3mLkgmin) underwent two intermittent moderate-high intensity aerobic exercise sessions separated by 2h of rest one day, followed by one session 24h later in a 40°C, 40% relative humidity environment. Heart rate, rectal temperature, heat stress perception, and environmental symptoms were assessed.

Results: 100%, 35%, and 71% of participants completed the full exercise protocol during the first exercise session, second exercise session, and the following day, respectively. Exercising heart rate and rectal temperature were greater during the second exercise session (189±11bpm, 38.80±0.47°C) than the first identical exercise session (180±17bpm, p=0.004; 38.41±0.52°C, p=0.001), respectively. Immediate post-exercise heart rate, rectal temperature, thirst, thermal sensation, fatigue, and perceived exertion were similar among exercise sessions despite a shorter exercise duration during the second exercise session (93±27min, p=0.001) and the following day (113±12min, p=0.032) than the first exercise session (120±0min).

Conclusions: Moderate-high-intensity intermittent exercise in the heat resulted in greater heat strain during a second exercise session the same day, and exercise the subsequent day.
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http://dx.doi.org/10.1016/j.jsams.2019.06.003DOI Listing
October 2019

Changes of Hydration Measures in Elite National Collegiate Athletic Association Division I Wrestlers.

Int J Sports Physiol Perform 2019 Oct 2:1-4. Epub 2019 Oct 2.

Purpose: To evaluate the changes in the state of hydration in elite National Collegiate Athletic Association (NCAA) Division I college wrestlers during and after a season.

Methods: Ohio State University wrestling team members (N = 6; mean [SD] age = 19.6 [1.1] y; height = 171.6 [2.9] cm; body mass = 69.5 [8.1] kg) gave informed consent to participate in the investigation with measurements (ie, body mass, urine-specific gravity [USG; 2 methods], Visual Analog Scale thirst scale, plasma osmolality) obtained during and after the season.

Results: Measurements for USG, regardless of methods, were not significantly different between visits, but plasma osmolality was significantly (P = .001) higher at the beginning of the season-295.5 (4.9) mOsm·kg-1 compared with 279.6 (6.1) mOsm·kg-1 after the season. No changes in thirst ratings were observed, and the 2 measures of USG were highly correlated (r > .9, P = .000) at each time point, but USG and plasma osmolality were not related.

Conclusions: A paradox in the clinical interpretation of euhydration in the beginning of the season was observed with the USG, indicating that the wrestlers were properly hydrated, while the plasma osmolality showed they were not. Thus, the tracking of hydration status during the season is a concern when using only NCAA policies and procedures. The wrestlers did return to normal euhydration levels after the season on both biomarkers, which is remarkable, as previous studies have indicated that this may not happen because of the reregulation of the osmol-regulatory center in the brain.
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http://dx.doi.org/10.1123/ijspp.2019-0059DOI Listing
October 2019

Extended Ketogenic Diet and Physical Training Intervention in Military Personnel.

Mil Med 2019 10;184(9-10):e538-e547

Department of Human Sciences, The Ohio State University, 305 Annie and John Glenn Avenue, Columbus, OH.

Introduction: Ketogenic diets (KDs) that elevate ketones into a range referred to as nutritional ketosis represent a possible nutrition approach to address the emerging physical readiness and obesity challenge in the military. An emerging body of evidence demonstrates broad-spectrum health benefits attributed to being in nutritional ketosis, but no studies have specifically explored the use of a KD in a military population using daily ketone monitoring to personalize the diet prescription.

Materials And Methods: To evaluate the feasibility, metabolic, and performance responses of an extended duration KD, healthy adults (n = 29) from various military branches participated in a supervised 12-wk exercise training program. Fifteen participants self-selected to an ad libitum KD guided by daily measures of capillary blood ketones and 14 continued their normal mixed diet (MD). A battery of tests were performed before and after the intervention to assess changes in body mass, body composition, visceral fat, liver fat, insulin sensitivity, resting energy metabolism, and physical performance.

Results: All KD subjects were in nutritional ketosis during the intervention as assessed by daily capillary beta-hydroxybutyrate (βHB) (mean βHB 1.2 mM reported 97% of all days) and showed higher rates of fat oxidation indicative of keto-adaptation. Despite no instruction regarding caloric intake, the KD group lost 7.7 kg body mass (range -3.5 to -13.6 kg), 5.1% whole-body percent fat (range -0.5 to -9.6%), 43.7% visceral fat (range 3.0 to -66.3%) (all p < 0.001), and had a 48% improvement in insulin sensitivity; there were no changes in the MD group. Adaptations in aerobic capacity, maximal strength, power, and military-specific obstacle course were similar between groups (p > 0.05).

Conclusions: US military personnel demonstrated high adherence to a KD and showed remarkable weight loss and improvements in body composition, including loss of visceral fat, without compromising physical performance adaptations to exercise training. Implementation of a KD represents a credible strategy to enhance overall health and readiness of military service members who could benefit from weight loss and improved body composition.
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http://dx.doi.org/10.1093/milmed/usz046DOI Listing
October 2019

Intermittent exercise-heat exposures and intense physical activity sustain heat acclimation adaptations.

J Sci Med Sport 2019 Jan 19;22(1):117-122. Epub 2018 Jun 19.

Department of Human Sciences, The Ohio State University, United States.

Objectives: To determine if intermittent exercise-heat exposures (IHE) every fifth day sustain heat acclimation (HA) adaptations 25 days after initial HA.

Design: Randomized control trial.

Methods: Sixteen non-heat acclimatized men heat acclimated during 10-11 days of exercise in the heat (40°C, 40% RH). A heat stress test (120min, 45% V˙O) before (Pre HA) and after HA (Post HA) in similar hot conditions assessed HA status. Pair-matched participants were randomized into a control group (CON; n=7) that exercised in a temperate environment (24°C, 21%RH) or IHE group (n=9) that exercised in a hot environment (40°C, 40%RH) every fifth day for 25 days following HA (+25d) with out-of-laboratory exercise intensity and duration recorded. Both groups completed +25d in the hot condition.

Results: Both groups heat acclimated similarly (p>0.05) evidenced by lower heart rate (HR), thermoregulatory, physiological, and perceptual responses (perceived exertion, fatigue, thermal sensation) Pre HA vs. Post HA (p≤0.05). At +25d, post-exercise HR (p=0.01) and physiological strain index (p<0.05) but neither T (p=0.18) nor sweat rate (p=0.44) were lower in IHE vs. CON. In IHE only, post-exercise T and perceptual responses at Post HA and +25d were lower than Pre HA (p≤0.01). +25d post-exercise epinephrine was higher in CON vs. IHE (p=0.04). Exercise intensity during out-of-lab exercise and +25d post-exercise HR were correlated (r=-0.89, p=0.02) in IHE.

Conclusions: Exercise-heat exposures every fifth day for 25 days and regular intense physical activity after HA sustained HR and T adaptations and reduced perceptual and physiological strain during exercise-heat stress ∼1 month later.
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http://dx.doi.org/10.1016/j.jsams.2018.06.009DOI Listing
January 2019

Paradox of hypercholesterolaemia in highly trained, keto-adapted athletes.

BMJ Open Sport Exerc Med 2018 4;4(1):e000429. Epub 2018 Oct 4.

Department of Human Sciences, The Ohio State University, Columbus, Ohio, USA.

Objective: A growing number of ultra-endurance athletes have switched to a very low-carbohydrate/high-fat eating pattern. We compared markers of cholesterol and the lipoprotein profile in a group of elite ultra-runners consuming a high-carbohydrate (HC) or low-carbohydrate (LC) diet.

Methods: Fasting blood was obtained from competitive male ultra-endurance runners habitually consuming a very low-carbohydrate (LC; n=10) or high-carbohydrate (HC; n=10) diet to determine blood cholesterol profile, lipoprotein particle distribution and sterol biomarkers of cholesterol balance.

Results: Plasma total cholesterol, low-density lipoprotein (LDL-C) and high-density lipoprotein (HDL-C) cholesterol were all significantly greater (p<0.000) in the LC group (65%, 83% and 60%, respectively). There were also significant differences in lipoprotein particle distribution as evidenced by a greater size and concentration of large HDL and LDL particles, and total LDL particle concentration was significantly greater in the LC group, but they had significantly fewer small LDL particles.

Conclusion: Ultra-endurance athletes habitually consuming a very low-carbohydrate/high-fat diet for over a year showed unique cholesterol profiles characterised by consistently higher plasma LDL-C and HDL-C, less small LDL particles, and lipoprotein profiles consistent with higher insulin sensitivity. There may be a functional purpose to the expansion of the circulating cholesterol pool to meet the heightened demand for lipid transport in highly trained, keto-adapted athletes.
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http://dx.doi.org/10.1136/bmjsem-2018-000429DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6173254PMC
October 2018

Evidence of the Exercise-Hypogonadal Male Condition at the 2011 Kona Ironman World Championships.

Int J Sports Physiol Perform 2019 Feb 3;14(2):170-175. Epub 2019 Jan 3.

Purpose: Prior research has illustrated that high volumes of aerobic exercise result in a reduction in basal concentrations of testosterone in men. Those studies were mostly conducted on recreational runners and identified reduced testosterone, but not concentrations low enough to be considered pathological. Therefore, the purpose of this study was to assess the basal concentrations of testosterone and cortisol in elite triathletes, as well as the impact of a World Championship race, on the acute responses of these hormones.

Methods: A total of 22 men (age 40.6 [11.5] y, height 179 [6] cm, weight 77.0 [7.0] kg) who participated in the 2011 Ironman World Championships served as subjects. Resting blood samples were taken 2-4 d prior to provide a baseline (BL), as well as immediately, 1 d, and 2 d after the event and were later analyzed for total testosterone and cortisol concentrations.

Results: At BL, 9 men had a normal testosterone concentration, whereas 9 men fell within a "gray zone" and 4 other men demonstrated concentrations suggestive of deficiency. Testosterone was significantly lower than BL at 1 d (95% confidence interval [CI] 0.10-0.34, P < .001, ES = 0.53) and 2 d (95% CI 0.01-0.21, P = .034, ES = 0.35) after the event. Cortisol was significantly different from BL at immediate post (95% CI 1.07-0.83, P < .001, ES = 8.0). There were significant correlations between time and age (R = .68, P = .001), as well as BL testosterone and cortisol (R = .51, P = .015).

Conclusion: Elite ultraendurance athletes may demonstrate not only reduced testosterone but also sometimes clinically low concentrations that could be indicative of androgen deficiency.
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http://dx.doi.org/10.1123/ijspp.2017-0476DOI Listing
February 2019

Influence of cold-water immersion on recovery of elite triathletes following the ironman world championship.

J Sci Med Sport 2018 Aug 31;21(8):846-851. Epub 2018 Jan 31.

Korey Stringer Institute, Department of Kinesiology, University of Connecticut, United States.

Objectives: Cold water immersion (CWI) has been widely used for enhancing athlete recovery though its use following an Ironman triathlon has never been examined. The purpose of this paper is to determine the influence of CWI immediately following an Ironman triathlon on markers of muscle damage, inflammation and muscle soreness.

Design: Prospective cohort study.

Methods: Thirty three (22 male, 11 female), triathletes participating in the Ironman World Championships volunteered to participate (mean±SD: age=40±11years; height=174.5±9.1cm; body mass=70±11.8kg; percent body fat=11.4±4.1%, finish time=11:03.00±01:25.08). Post race, participants were randomly assigned to a 10-min bout of 10°C CWI or no-intervention control group. Data collection occurred pre-intervention (PRE), post-intervention (POST), 16h (16POST) and 40h (40POST) following the race. Linear mixed model ANOVA with Bonferroni corrections were performed to examine group by time differences for delayed onset muscle soreness (DOMS), hydration indices, myoglobin, creatine kinase (CK), cortisol, C-reactive protein (CRP), IL-6 and percent body mass loss (%BML). Pearson's bivariate correlations were used for comparisons with finishing time. Alpha level was set a priori at 0.05.

Results: No significant group by time interactions occurred. Significant differences occurred for POST BML (-1.7±0.9kg) vs. 16POST, and 40POST BML (0.9±1.4, -0.1±1.2kg, respectively; p<0.001). Compared to PRE, myoglobin, CRP and CK remained significantly elevated at 40POST. Cortisol returned to PRE values by 16POST and IL-6 returned to PRE values by 40POST.

Conclusion: A single bout of CWI did not provide any physiological benefit during recovery from a triathlon within 40h post race. Effect of CWI beyond this time is unknown.
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http://dx.doi.org/10.1016/j.jsams.2017.12.011DOI Listing
August 2018

Adrenal Stress and Physical Performance During Military Survival Training.

Aerosp Med Hum Perform 2018 Feb;89(2):99-107

Department of Kinesiology, The Ohio State University, Columbus OH, USA.

Introduction: The purpose of this research was to evaluate neuroendocrine and physical performance responses in sailors and Marines undergoing U.S. Navy Survival, Evasion, Resistance, and Escape (SERE) training.

Methods: Participants were 20 men (Age: 25.3 ± 3.6 yr; Height: 178.1 ± 6.1 cm; Weight: 83.7 ± 12.6 kg). Men were further split into high fit (N = 10) and low fit (N = 10) subgroups based on physical fitness test scores. Blood samples were obtained at baseline (T1), stress (T2), and recovery (T3) timepoints, and were analyzed for plasma epinephrine, plasma norepinephrine, plasma dopamine, serum cortisol, serum testosterone, and plasma neuropeptide Y. Vertical jump and handgrip tests were performed at T1 and T2.

Results: Stress hormone concentrations were significantly elevated at T2, with a concomitant reduction in testosterone concentrations. NPY concentrations did not increase at T2, but decreased significantly at T3. Subjects maintained performance on vertical jump and handgrip tests from T1 to T2. Significant between group differences were observed in norepinephrine (high fit: 3530.64 ± 2146.54 pmol · L-1, low fit: 4907.16 ± 3020.85 pmol · L-1) and NPY (high fit: 169.30 ± 85.89 pg · ml-1, low fit: 123.02 ± 88.86 pg · ml-1) concentrations at T3.

Conclusion: This study revealed that despite significant increases in stress hormone concentrations in all subjects during SERE, fitter subjects exhibited differential hormonal responses during recovery, with quicker return of norepinephrine and NPY to baseline concentrations. This suggests physical fitness level may have a protective effect in recovery from periods of high stress military training.Szivak TK, Lee EC, Saenz C, Flanagan SD, Focht BC, Volek JS, Maresh CM, Kraemer WJ. Adrenal stress and physical performance during military survival training. Aerosp Med Hum Perform. 2018; 89(2):99-107.
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http://dx.doi.org/10.3357/AMHP.4831.2018DOI Listing
February 2018

The presence of symptoms of testosterone deficiency in the exercise-hypogonadal male condition and the role of nutrition.

Eur J Appl Physiol 2017 Jul 3;117(7):1349-1357. Epub 2017 May 3.

Department of Human Sciences, The Ohio State University, A054 PAES Building, 305 Annie and John Glenn Avenue, Columbus, OH, 43210, USA.

Purpose: High volumes of aerobic exercise have been associated with reduced testosterone (T), known as the exercise-hypogonadal male condition (EHMC). Although the presence of low T has been identified, few studies have assessed the presence of androgen-deficient symptoms. The purpose of this investigation is to assess men exhibiting EHMC and evaluate their hypothalamic-pituitary-gonadal axis, the presence of hypogonadal symptoms, and also investigate a possible contribution of inadequate nutrition to the condition.

Methods: A cross-sectional design compared 9 long-distance runners exhibiting EHMC to 8 non-active controls. Comparisons included serum T, luteinizing hormone (LH), follicle-stimulating hormone, and cortisol, the Aging Male Symptoms (AMS) questionnaire score, bone mineral density (BMD), and a food frequency questionnaire.

Results: Mean T was significantly reduced in the EHMC group (EHMC 9.2 nmol L vs. CONT 16.2 nmol L). The EHMC group demonstrated significantly higher AMS scores (EHMC 27.1 ± 7.3 vs. CONT 19.7 ± 2.5). There were no differences in bone density, although 3 cases of osteopenia were noted for EHMC in the lumbar spine, 1 in the right femur, and 1 in the radius. Energy availability was significantly reduced in EHMC (EHMC 27.2 ± 12.7 vs. CONT 45.4 ± 18.2 kcal d FFM).

Conclusions: Men exhibiting EHMC do appear to present with symptoms associated with androgen deficiency. For the most part, these symptoms are limited to those reported on the AMS questionnaire, although there are also some cases of clinically low BMD. It is possible that inadequate energy intake is contributing to this condition.
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http://dx.doi.org/10.1007/s00421-017-3623-zDOI Listing
July 2017

The effects of different exercise training modalities on plasma proenkephalin Peptide F in women.

Peptides 2017 05 3;91:26-32. Epub 2017 Mar 3.

Department of Human Sciences, The Ohio State University, Columbus, OH, United States.

Due to the important interactions of proenkephalin fragments (e.g., proenkephalin [107-140] Peptide F) to enhance activation of immune cells and potentially combat pain associated with exercise-induced muscle tissue damage, we examined the differential plasma responses of Peptide F to different exercise training programs. Participants were tested pre-training (T1), and after 8 weeks (T2) of training. Fifty-nine healthy women were matched and then randomly assigned to one of four groups: heavy resistance strength training (STR, n=18), high intensity endurance training (END, n=14), combined strength and endurance training (CMB, n=17), or control (CON, n=10). Blood was collected using a cannula inserted into a superficial vein in the antecubital fossa with samples collected at rest and immediately after an acute bout of 6 X 10 RM in a squat resistance exercise before training and after training. Prior to any training, no significant differences were observed for any of the groups before or after acute exercise. With training, significant (P≤0.95) elevations were observed with acute exercise in each of the exercise training groups and this effect was significantly greater in the CMB group. These data indicate that in untrained women exercise training will not change resting of plasma Peptide F concentrations unless both forms of exercise are performed but will result in significant increases in the immediate post-exercise responses. Such findings appear to indicate adrenal medullary adaptations opioid production significantly altered with exercise training.
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http://dx.doi.org/10.1016/j.peptides.2017.02.006DOI Listing
May 2017

Endocrinological Roles for Testosterone in Resistance Exercise Responses and Adaptations.

Sports Med 2017 Sep;47(9):1709-1720

Department of Human Sciences, The Ohio State University, A054 PAES Building, 305 Annie and John Glenn Avenue, Columbus, OH, 43210, USA.

Chronic increases in testosterone levels can significantly increase hypertrophy and strength, as has been demonstrated by pharmacological intervention. However, decreases in basal testosterone levels can have the opposite result, as has been seen in hypogonadal populations. Because of these profound effects on hypertrophy and strength, testosterone has often been studied in conjunction with resistance exercise to examine whether the endocrine system plays a role in adaptations to the stimulus. Whereas some studies have demonstrated a chronic increase in basal testosterone, others have failed to find an adaptation to regular resistance exercise. However, improvements in strength and hypertrophy appear to be possible regardless of the presence of this adaptation. Testosterone has also been shown to acutely rise immediately following an acute resistance exercise bout. While this substantial mobilization of testosterone is brief, its effects are seen for several hours through the upregulation of the androgen receptor. The role of this acute response at present is unknown, but further study of the non-genomic action and possible intracrinological processes is warranted. This response does not seem to be necessary for resistance training adaptations to occur either, but whether this response optimizes such adaptations has not yet been determined.
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http://dx.doi.org/10.1007/s40279-017-0698-yDOI Listing
September 2017

Heat Exposure and Hypohydration Exacerbate Physiological Strain During Load Carrying.

J Strength Cond Res 2019 Mar;33(3):727-735

Department of Human Sciences, The Ohio State University, Columbus, Ohio.

Adams, EL, Casa, DJ, Huggins, RA, DeMartini-Nolan, JK, Stearns, RL, Kennedy, RM, Bosworth, MM, DiStefano, LJ, Armstrong, LE, and Maresh, CM. Heat exposure and hypohydration exacerbate physiological strain during load carrying. J Strength Cond Res 33(3): 727-735, 2019-Heat exposure and hypohydration induce physiological and psychological strain during exercise; however, it is unknown if the separate effects of heat exposure and hypohydration are synergistic when co-occurring during loaded exercise. This study compared separate and combined effects of heat exposure and hypohydration on physiological strain, mood state, and visual vigilance during loaded exercise. Twelve men (mean ± SD; age, 20 ± 2 years; body mass, 74.0 ± 8.2 kg; maximal oxygen uptake, 57.0 ± 6.0 ml·kg·min) completed 4 trials under the following conditions: euhydrated temperate (EUT), hypohydrated temperate (HYT), euhydrated hot (EUH), and hypohydrated hot (HYH). Exercise was 90 minutes of treadmill walking (∼50% V[Combining Dot Above]O2max, 5% grade) while carrying a 45-lb rucksack. Profile of Mood States and the Scanning Visual Vigilance Test were completed before and after exercise. The separate effects of heat exposure (EUH) and hypohydration (HYT) on post-exercise rectal temperature (Tre) were similar (38.25 ± 0.63°C vs. 38.22 ± 0.29°C, respectively, p > 0.05), whereas in combination (HYH), post-exercise Tre was far greater (39.32 ± 0.43°C). Increase in Tre per 1% body mass loss (BML) for HYH (vs. EUH) was greater than HYT (vs. EUT) (0.32 vs. 0.04°C, respectively, p = 0.02); heart rate increase per 1% BML for HYH (vs. EUH) was 7 b·min compared with HYT (vs. EUT) at 3 b·min (p = 0.30). Hypohydrated hot induced greater mood disturbance (post-exercise - pre-exercise) (35 ± 21 units) compared with other conditions (EUT = 3 ± 9 units; HYT = 3 ± 16 units; EUH = 16 ± 26 units; p < 0.001). No differences occurred in visual vigilance (p > 0.05). Independently, heat exposure and hypohydration induced similar physiological strain during loaded exercise; when combined, heat exposure with hypohydration, synergistically exacerbated physiological strain and mood disturbance.
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March 2019

The effects of a transcontinental flight on markers of coagulation and fibrinolysis in healthy men after vigorous physical activity.

Chronobiol Int 2017 4;34(2):148-161. Epub 2016 Nov 4.

b Department of Human Sciences , The Ohio State University , Columbus , OH , USA.

Purpose: Athletes and military service members are known to undergo strenuous exercise and sometimes have to take long haul flights soon afterwards; however, its combined effect on many physiological functions is relatively unknown. Therefore, we examined the combined effects of a full-body muscle-damaging workout and transcontinental flight on coagulation and fibrinolysis in healthy, resistance trained men. We also determined the efficacy of a full-body compression garment in limiting their coagulation responses.

Materials And Methods: Nineteen healthy, resistance trained men flew from Connecticut (CT) to California (CA), performed a full-body muscle-damaging workout and then flew back to CT. Ten participants wore full-body compression garments (FCG) for the duration of both flights and during all other portions of the study except during workouts and blood draws, when they wore loose clothing. Nine controls wore loose clothing (CON) throughout the study. Blood samples were collected at 16 h and 3 h before the initial flight from CT, immediately after landing in CA, immediately before and immediately after the full-body workout in CA, immediately after landing in CT, and at 29 h after landing in CT. Plasma markers of coagulation included activated partial thromboplastin time (aPTT), prothrombin fragment 1+2 (PTF 1+2) and thrombin ant-thrombin (TAT). Markers of the fibrinolytic system included the tissue plasmigen activator (tPA), plasminogen activator inhibitor-1 (PAI-1) and D-Dimer.

Results: Both FCG and CON groups exhibited a faster aPTT after the full-body workout compared to all other time points.  Thrombin generation markers, TAT and PTF 1+2, increased significantly after the full-body workout and immediately after landing in CT. Additionally, tPA increased after the full-body workout, while PAI-1 increased before the flight to CA, after the full-body workout, and just after landing in CT. The D-Dimer significantly increased after the full-body workout and at 29 h post-flight in both groups. Between groups, aPTT was significantly faster and TAT elevated with the CON group at 29 h post-flight. Also, PAI-1 demonstrated higher concentrations immediately after landing in CT for the CON group.

Conclusion: A full-body muscle-damaging workout in conjunction with a trans-continental flight activated the coagulation and fibrinolytic systems. Additionally, wearing a full-body compression garment may limit coagulation following a workout through the recovery period.
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http://dx.doi.org/10.1080/07420528.2016.1247851DOI Listing
February 2018

Relationships between hydration biomarkers and total fluid intake in pregnant and lactating women.

Eur J Nutr 2017 Sep 12;56(6):2161-2170. Epub 2016 Aug 12.

Department of Kinesiology, Human Performance Laboratory, University of Connecticut, 2095 Hillside Road, Storrs, CT, 06269-1110, USA.

Introduction: Previous research established significant relationships between total fluid intake (TFI) and urinary biomarkers of the hydration process in free-living males and females; however, the nature of this relationship is not known for pregnant (PREG) and lactating (LACT) women.

Purpose: To determine the relationship between urinary and hematological hydration biomarkers with TFI in PREG and LACT.

Methods: Eighteen PREG/LACT (age: 31 ± 3 years, pre-pregnancy BMI: 24.26 ± 5.85 kg m) collected 24-h urine samples, recorded TFI, and provided a blood sample at 5 time points (15 ± 2, 26 ± 1, 37 ± 1 weeks gestation, 3 ± 1 and 9 ± 1 weeks postpartum during lactation); 18 pair-matched non-pregnant (NP), non-lactating (NL) women (age: 29 ± 4 years, BMI: 24.1 ± 3.7 kg m) provided samples at similar time intervals. Twenty-four-hour urine volume (U ), osmolality (U ), specific gravity (U ), and color (U ) were measured. Hematocrit, serum osmolality (S ), and serum total protein (S ) were measured in blood.

Results: Significant relationships were present between TFI and urinary biomarkers in all women (P < 0.004); these relationships were not different between PREG and NP, and LACT and NL, except U in PREG (P = 0.0017). No significant relationships between TFI and hematological biomarkers existed (P > 0.05).

Conclusion: Urinary biomarkers of hydration, but not hematological biomarkers, have a strong relationship with TFI in PREG, LACT, NP, and NL women. These data suggest that urinary biomarkers of hydration reflect TFI during pregnancy and breast-feeding.
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http://dx.doi.org/10.1007/s00394-016-1256-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5579181PMC
September 2017

Precision, Accuracy, and Performance Outcomes of Perceived Exertion vs. Heart Rate Guided Run-training.

J Strength Cond Res 2017 Mar;31(3):630-637

1Human Integrated Physiology Laboratory, University of Wyoming, Laramie, Wyoming; 2Human Performance Laboratory, University of Connecticut, Storrs, Connecticut; 3Department of Kinesiology, California State University Fresno, Fresno, California; 4School of Health and Exercise Sciences, University of British Columbia, Onkanagan, British Columbia; 5Department of Human Sciences, The Ohio State University, Columbus, Ohio; and 6Human Performance Laboratory, University of Arkansas, Fayetteville, Arkansas.

Johnson, EC, Pryor, RR, Casa, DJ, Ellis, LA, Maresh, CM, Pescatello, LS, Ganio, MS, Lee, EC, and Armstrong, LE. Precision, accuracy, and performance outcomes of perceived exertion vs. heart rate guided run-training. J Strength Cond Res 31(3): 630-637, 2017-The purpose of this investigation was to compare run-prescription by heart rate (HR) vs. rating of perceived exertion (RPE) during 6 weeks to determine which is superior for consistent achievement of target intensities and improved performance. Forty untrained men participated in this laboratory-controlled and field-controlled trial. Participants were divided into heart rate (HRTG) and rating of perceived exertion training groups (RPETG). All underwent maximal-graded exercise testing and a 12-minute run test before and after training. Intensity was prescribed as either a target HR or RPE that corresponded to 4 relative intensity levels: 45, 60, 75, and 90% V[Combining Dot Above]O2 reserve (V[Combining Dot Above]O2R). Mean exercise intensity over the 6 weeks did not differ between HRTG (65.6 ± 7.2%HRR) and RPETG (61.9 ± 9.0%HRR). V[Combining Dot Above]O2max (+4.1 ± 2.5 ml·kg·min) and 12 minutes run distance (+240.1 ± 150.1 m) improved similarly in HRTG and RPETG (p > 0.05). HRTG displayed lower coefficients of variation (CV) (5.9 ± 4.1%, 3.3 ± 3.8%, and 3.0 ± 2.2%) and %error (4.1 ± 4.7%, 2.3 ± 4.1% and 2.6 ± 3.2%) at 45, 60, and 75% V[Combining Dot Above]O2R compared with RPETG (CV 11.1 ± 5.0%, 7.7 ± 4.1% and 5.6 ± 3.2%; all p < 0.005) %error (15.7 ± 9.2%, 10.6 ± 9.2% and 6.7 ± 3.2%; all p < 0.001), respectively. Overall, HR-prescribed and RPE-prescribed run-training resulted in similar exercise intensity and performance outcomes over 6 weeks. Differences in the CV and %error suggest use of HR monitoring for individuals that are new to running as it improves precision and accuracy but does not increase performance improvements across 6 weeks.
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March 2017

The effects of a roundtrip trans-American jet travel on physiological stress, neuromuscular performance, and recovery.

J Appl Physiol (1985) 2016 08 9;121(2):438-48. Epub 2016 Jun 9.

Department of Human Sciences, The Ohio State University, Columbus, Ohio;

The purpose was to examine the effects of a round trip trans-American jet travel on performance, hormonal alterations, and recovery. Ten matched pairs of recreationally trained men were randomized to either a compression group (COMP) (n = 10; age: 23.1 ± 2.4 yr; height: 174.8 ± 5.3 cm; body mass: 84.9 ± 10.16 kg; body fat: 15.3 ± 6.0%) or control group (CONT) (n = 9; age: 23.2 ± 2.3 yr; height: 177.5 ± 6.3 cm; weight: 84.3 ± 8.99 kg; body fat: 15.1 ± 6.4%). Subjects flew directly from Hartford, CT to Los Angeles, CA 1 day before a simulated sport competition (SSC) designed to create muscle damage and returned the next morning on an overnight flight back home. Both groups demonstrated jet lag symptoms and associated decreases in sleep quality at all time points. Melatonin significantly (P < 0.05) increased over the first 2 days and then remained constant until after the SSC. Epinephrine, testosterone, and cortisol values significantly increased above resting values before and after the SSC with norepinephrine increases only after the SSC. Physical performances significantly decreased from control values on each day for the CONT group with COMP group exhibiting no significant declines. Muscle damage markers were significantly elevated following the SSC with the COMP group having significantly lower values while maintaining neuromuscular performance measures that were not different from baseline testing. Trans-American jet travel has a significant impact on parameters related to jet lag, sleep quality, hormonal responses, muscle tissue damage markers, and physical performance with an attenuation observed with extended wear compression garments.
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http://dx.doi.org/10.1152/japplphysiol.00429.2016DOI Listing
August 2016

Hormonal and Thirst Modulated Maintenance of Fluid Balance in Young Women with Different Levels of Habitual Fluid Consumption.

Nutrients 2016 May 18;8(5). Epub 2016 May 18.

Human Performance Laboratory, Department of Kinesiology, University of Connecticut, Storrs, CT 06269, USA.

Background: Surprisingly little is known about the physiological and perceptual differences of women who consume different volumes of water each day. The purposes of this investigation were to (a) analyze blood osmolality, arginine vasopressin (AVP), and aldosterone; (b) assess the responses of physiological, thirst, and hydration indices; and (c) compare the responses of individuals with high and low total water intake (TWI; HIGH and LOW, respectively) when consuming similar volumes of water each day and when their habitual total water intake was modified.

Methods: In a single-blind controlled experiment, we measured the 24 h total water intake (TWI; water + beverages + food moisture) of 120 young women. Those who consumed the highest (HIGH, 3.2 ± 0.6 L·day(-1), mean ± SD) and the lowest (LOW, 1.6 ± 0.5 L·day(-1)) mean habitual TWI were identified and compared. Outcome variables were measured during two ad libitum baseline days, a four-day intervention of either decreased TWI (HIGH) or increased TWI (LOW), and one ad libitum recovery day.

Results: During the four-day intervention, HIGH and LOW experienced differences in thirst (p = 0.002); also, a statistically significant change of AVP occurred (main effect of TWI and day, p < 0.001), with no effect (TWI or day) on aldosterone and serum osmolality. Urine osmolality and volume distinguished HIGH from LOW (p = 0.002) when they consumed similar 24 h TWI.
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http://dx.doi.org/10.3390/nu8050302DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4882714PMC
May 2016

Metabolic characteristics of keto-adapted ultra-endurance runners.

Metabolism 2016 Mar 2;65(3):100-10. Epub 2015 Nov 2.

School of Medicine (emeritus), University of California, Davis, Davis, CA, USA.

Background: Many successful ultra-endurance athletes have switched from a high-carbohydrate to a low-carbohydrate diet, but they have not previously been studied to determine the extent of metabolic adaptations.

Methods: Twenty elite ultra-marathoners and ironman distance triathletes performed a maximal graded exercise test and a 180 min submaximal run at 64% VO2max on a treadmill to determine metabolic responses. One group habitually consumed a traditional high-carbohydrate (HC: n=10, %carbohydrate:protein:fat=59:14:25) diet, and the other a low-carbohydrate (LC; n=10, 10:19:70) diet for an average of 20 months (range 9 to 36 months).

Results: Peak fat oxidation was 2.3-fold higher in the LC group (1.54±0.18 vs 0.67±0.14 g/min; P=0.000) and it occurred at a higher percentage of VO2max (70.3±6.3 vs 54.9±7.8%; P=0.000). Mean fat oxidation during submaximal exercise was 59% higher in the LC group (1.21±0.02 vs 0.76±0.11 g/min; P=0.000) corresponding to a greater relative contribution of fat (88±2 vs 56±8%; P=0.000). Despite these marked differences in fuel use between LC and HC athletes, there were no significant differences in resting muscle glycogen and the level of depletion after 180 min of running (-64% from pre-exercise) and 120 min of recovery (-36% from pre-exercise).

Conclusion: Compared to highly trained ultra-endurance athletes consuming an HC diet, long-term keto-adaptation results in extraordinarily high rates of fat oxidation, whereas muscle glycogen utilization and repletion patterns during and after a 3 hour run are similar.
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March 2016

The Effects of Nitrate-Rich Supplementation on Neuromuscular Efficiency during Heavy Resistance Exercise.

J Am Coll Nutr 2016 17;35(2):100-7. Epub 2016 Feb 17.

a Department of Human Sciences , The Ohio State University, Columbus, Ohio (S.D.F., W.H.D., B.C.C., A.J.S., T.K.S., D.R.H., C.M.M., J.S.V., W.J.K.); Department of Kinesiology, University of Connecticut, Storrs, Connecticut (D.P.L., L.P., B.C.C., L.A.E.); Healthy Directions , Bethesda , Maryland (M.J.S.M.).

Objective: Nitrate-rich (NR) supplements can enhance exercise performance by improving neuromuscular function and the aerobic cost of exercise. However, little is known about the effects of nitrate on dynamic, multijoint resistance exercise.

Methods: Fourteen resistance-trained men (age, 21.1 ± 0.9 years; height, 173.2 ± 2.9 cm: body mass, 77.6 ± 4.3 kg; squat one-repetition maximum [1RM], 127.5 ± 18.8 kg) participated in a randomized, double-blind, crossover experiment. Subjects consumed an NR or nitrate-poor (NP) supplement for 3 days, performed a bout of heavy resistance exercise, completed a washout, and then repeated the procedures with the remaining supplement. Before, during, and after exercise, individual and gross motor unit efficiency was assessed during isometric and dynamic muscle contractions. In addition, we compared physical performance, heart rate, lactate, and oxygen consumption (VO2).

Results: Nitrate-rich supplementation resulted in lower initial muscle firing rates at rest and lower mean and maximum firing rates over the course of fatiguing exercise. Nitrate-poor supplementation was accompanied by increased mean and maximum firing rates by the end of exercise and lower initial firing rates. In addition, NR supplementation resulted in higher mean peak electromyography (EMG) amplitudes. Heart rate, lactate, and physical performance did not differ by treatment, but oxygen consumption increased more frequently when the NP supplement was consumed.

Conclusion: Supplementation with an NR beetroot extract-based supplement provided neuromuscular advantages during metabolically taxing resistance exercise.
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http://dx.doi.org/10.1080/07315724.2015.1081572DOI Listing
December 2016

Comparison of Two Fluid Replacement Protocols During a 20-km Trail Running Race in the Heat.

J Strength Cond Res 2016 Sep;30(9):2609-16

1Morsani College of Medicine, University of South Florida, Tampa, Florida; 2Department of Kinesiology, Korey Stringer Institute, University of Connecticut, Storrs, Connecticut; 3College of Health Professions, Sacred Heart University, Fairfield, CT; 4Department of Kinesiology, Temple University, Philadelphia, Pennsylvania; 5Department of Movement Science, Sport & Leisure Studies, Westfield State University, Westfield, Massachusetts; and 6Department of Human Sciences, Ohio State University, Columbus, Ohio.

Lopez, RM, Casa, DJ, Jensen, K, Stearns, RL, DeMartini, JK, Pagnotta, KD, Roti, MW, Armstrong, LE, and Maresh, CM. Comparison of two fluid replacement protocols during a 20-km trail running race in the heat. J Strength Cond Res 30(9): 2609-2616, 2016-Proper hydration is imperative for athletes striving for peak performance and safety, however, the effectiveness of various fluid replacement strategies in the field setting is unknown. The purpose of this study was to investigate how two hydration protocols affect physiological responses and performance during a 20-km trail running race. A randomized, counter-balanced, crossover design was used in a field setting (mean ± SD: WBGT 28.3 ± 1.9° C). Well-trained male (n = 8) and female (n = 5) runners (39 ± 14 years; 175 ± 9 cm; 67.5 ± 11.1 kg; 13.4 ± 4.6% BF) completed two 20-km trail races (5 × 4-km loop) with different water hydration protocols: (a) ad libitum (AL) consumption and (b) individualized rehydration (IR). Data were analyzed using repeated measures ANOVA. Paired t-tests compared pre-race-post-race measures. Main outcome variables were race time, heart rate (HR), gastrointestinal temperature (TGI), fluid consumed, percent body mass loss (BML), and urine osmolality (Uosm). Race times between groups were similar. There was a significant condition × time interaction (p = 0.048) for HR, but TGI was similar between conditions. Subjects replaced 30 ± 14% of their water losses in AL and 64 ± 16% of their losses in IR (p < 0.001). Ad libitum trial experienced greater BML (-2.6 ± 0.5%) compared with IR (-1.3 ± 0.5%; p < 0.001). Pre-race to post-race Uosm differences existed between AL (-273 ± 146 mOsm) and IR (-145 ± 215 mOsm, p = 0.032). In IR, runners drank twice as much fluid than AL during the 20-km race, leading to > 2% BML in AL. Ad libitum drinking resulted in 1.3% greater BML over the 20-km race, which resulted in no thermoregulatory or performance differences from IR.
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http://dx.doi.org/10.1519/JSC.0000000000001359DOI Listing
September 2016