Publications by authors named "Louise M Burke"

199 Publications

International Society of Sports Nutrition position stand: sodium bicarbonate and exercise performance.

J Int Soc Sports Nutr 2021 Sep 9;18(1):61. Epub 2021 Sep 9.

Performance & Physique Enhancement Laboratory, University of South Florida, Tampa, FL, 33612, USA.

Based on a comprehensive review and critical analysis of the literature regarding the effects of sodium bicarbonate supplementation on exercise performance, conducted by experts in the field and selected members of the International Society of Sports Nutrition (ISSN), the following conclusions represent the official Position of the Society: 1. Supplementation with sodium bicarbonate (doses from 0.2 to 0.5 g/kg) improves performance in muscular endurance activities, various combat sports, including boxing, judo, karate, taekwondo, and wrestling, and in high-intensity cycling, running, swimming, and rowing. The ergogenic effects of sodium bicarbonate are mostly established for exercise tasks of high-intensity that last between 30 s and 12 min. 2. Sodium bicarbonate improves performance in single- and multiple-bout exercise. 3. Sodium bicarbonate improves exercise performance in both men and women. 4. For single-dose supplementation protocols, 0.2 g/kg of sodium bicarbonate seems to be the minimum dose required to experience improvements in exercise performance. The optimal dose of sodium bicarbonate dose for ergogenic effects seems to be 0.3 g/kg. Higher doses (e.g., 0.4 or 0.5 g/kg) may not be required in single-dose supplementation protocols, because they do not provide additional benefits (compared with 0.3 g/kg) and are associated with a higher incidence and severity of adverse side-effects. 5. For single-dose supplementation protocols, the recommended timing of sodium bicarbonate ingestion is between 60 and 180 min before exercise or competition. 6. Multiple-day protocols of sodium bicarbonate supplementation can be effective in improving exercise performance. The duration of these protocols is generally between 3 and 7 days before the exercise test, and a total sodium bicarbonate dose of 0.4 or 0.5 g/kg per day produces ergogenic effects. The total daily dose is commonly divided into smaller doses, ingested at multiple points throughout the day (e.g., 0.1 to 0.2 g/kg of sodium bicarbonate consumed at breakfast, lunch, and dinner). The benefit of multiple-day protocols is that they could help reduce the risk of sodium bicarbonate-induced side-effects on the day of competition. 7. Long-term use of sodium bicarbonate (e.g., before every exercise training session) may enhance training adaptations, such as increased time to fatigue and power output. 8. The most common side-effects of sodium bicarbonate supplementation are bloating, nausea, vomiting, and abdominal pain. The incidence and severity of side-effects vary between and within individuals, but it is generally low. Nonetheless, these side-effects following sodium bicarbonate supplementation may negatively impact exercise performance. Ingesting sodium bicarbonate (i) in smaller doses (e.g., 0.2 g/kg or 0.3 g/kg), (ii) around 180 min before exercise or adjusting the timing according to individual responses to side-effects, (iii) alongside a high-carbohydrate meal, and (iv) in enteric-coated capsules are possible strategies to minimize the likelihood and severity of these side-effects. 9. Combining sodium bicarbonate with creatine or beta-alanine may produce additive effects on exercise performance. It is unclear whether combining sodium bicarbonate with caffeine or nitrates produces additive benefits. 10. Sodium bicarbonate improves exercise performance primarily due to a range of its physiological effects. Still, a portion of the ergogenic effect of sodium bicarbonate seems to be placebo-driven.
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http://dx.doi.org/10.1186/s12970-021-00458-wDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8427947PMC
September 2021

Neither Beetroot Juice Supplementation nor Increased Carbohydrate Oxidation Enhance Economy of Prolonged Exercise in Elite Race Walkers.

Nutrients 2021 Aug 12;13(8). Epub 2021 Aug 12.

Australian Institute of Sport, Bruce, Canberra, ACT 2616, Australia.

Given the importance of exercise economy to endurance performance, we implemented two strategies purported to reduce the oxygen cost of exercise within a 4 week training camp in 21 elite male race walkers. Fourteen athletes undertook a crossover investigation with beetroot juice (BRJ) or placebo (PLA) [2 d preload, 2 h pre-exercise + 35 min during exercise] during a 26 km race walking at speeds simulating competitive events. Separately, 19 athletes undertook a parallel group investigation of a multi-pronged strategy (MAX; = 9) involving chronic (2 w high carbohydrate [CHO] diet + gut training) and acute (CHO loading + 90 g/h CHO during exercise) strategies to promote endogenous and exogenous CHO availability, compared with strategies reflecting lower ranges of current guidelines (CON; = 10). There were no differences between BRJ and PLA trials for rates of CHO ( = 0.203) or fat ( = 0.818) oxidation or oxygen consumption ( = 0.090). Compared with CON, MAX was associated with higher rates of CHO oxidation during exercise, with increased exogenous CHO use (CON; peak = ~0.45 g/min; MAX: peak = ~1.45 g/min, < 0.001). High rates of exogenous CHO use were achieved prior to gut training, without further improvement, suggesting that elite athletes already optimise intestinal CHO absorption via habitual practices. No differences in exercise economy were detected despite small differences in substrate use. Future studies should investigate the impact of these strategies on sub-elite athletes' economy as well as the performance effects in elite groups.
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http://dx.doi.org/10.3390/nu13082767DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8398364PMC
August 2021

The Validity of Ultrasound Technology in Providing an Indirect Estimate of Muscle Glycogen Concentrations Is Equivocal.

Nutrients 2021 Jul 11;13(7). Epub 2021 Jul 11.

Exercise and Nutrition Research Group, Mary McKillop Institute for Health Research, Australian Catholic University, Melbourne, VIC 3000, Australia.

Researchers and practitioners in sports nutrition would greatly benefit from a rapid, portable, and non-invasive technique to measure muscle glycogen, both in the laboratory and field. This explains the interest in MuscleSound, the first commercial system to use high-frequency ultrasound technology and image analysis from patented cloud-based software to estimate muscle glycogen content from the echogenicity of the ultrasound image. This technique is based largely on muscle water content, which is presumed to act as a proxy for glycogen. Despite the promise of early validation studies, newer studies from independent groups reported discrepant results, with MuscleSound scores failing to correlate with the glycogen content of biopsy-derived mixed muscle samples or to show the expected changes in muscle glycogen associated with various diet and exercise strategies. The explanation of issues related to the site of assessment do not account for these discrepancies, and there are substantial problems with the premise that the ratio of glycogen to water in the muscle is constant. Although further studies investigating this technique are warranted, current evidence that MuscleSound technology can provide valid and actionable information around muscle glycogen stores is at best equivocal.
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http://dx.doi.org/10.3390/nu13072371DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8308826PMC
July 2021

The Utility of the Low Energy Availability in Females Questionnaire to Detect Markers Consistent With Low Energy Availability-Related Conditions in a Mixed-Sport Cohort.

Int J Sport Nutr Exerc Metab 2021 Jul 20:1-11. Epub 2021 Jul 20.

Australian Catholic University.

The Low Energy Availability in Females Questionnaire (LEAF-Q) was validated to identify risk of the female athlete triad (triad) in female endurance athletes. This study explored the ability of the LEAF-Q to detect conditions related to low energy availability (LEA) in a mixed sport cohort of female athletes. Data included the LEAF-Q, SCOFF Questionnaire for disordered eating, dual-energy X-ray absorptiometry-derived body composition and bone mineral density, Mini International Neuropsychiatric Interview, blood pressure, and blood metabolic and reproductive hormones. Participants were grouped according to LEAF-Q score (≥8 or <8), and a comparison of means was undertaken. Sensitivity, specificity, and predictive values of the overall score and subscale scores were calculated in relation to the triad and biomarkers relevant to LEA. Fisher's exact test explored differences in prevalence of these conditions between groups. Seventy-five athletes (18-32 years) participated. Mean LEAF-Q score was 8.0 ± 4.2 (55% scored ≥8). Injury and menstrual function subscale scores identified low bone mineral density (100% sensitivity, 95% confidence interval [15.8%, 100%]) and menstrual dysfunction (80.0% sensitivity, 95% confidence interval [28.4%, 99.5%]), respectively. The gastrointestinal subscale did not detect surrogate markers of LEA. LEAF-Q score cannot be used to classify athletes as "high risk" of conditions related to LEA, nor can it be used as a surrogate diagnostic tool for LEA given the low specificity identified. Our study supports its use as a screening tool to rule out risk of LEA-related conditions or to create selective low-risk groups that do not need management as there were generally high negative predictive values (range 76.5-100%) for conditions related to LEA.
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http://dx.doi.org/10.1123/ijsnem.2020-0233DOI Listing
July 2021

Overtraining Syndrome (OTS) and Relative Energy Deficiency in Sport (RED-S): Shared Pathways, Symptoms and Complexities.

Sports Med 2021 Jun 28. Epub 2021 Jun 28.

Australian Institute of Sport, Bruce, ACT, Australia.

The symptom similarities between training-overload (with or without an Overtraining Syndrome (OTS) diagnosis) and Relative Energy Deficiency in Sport (RED-S) are significant, with both initiating from a hypothalamic-pituitary origin, that can be influenced by low carbohydrate (CHO) and energy availability (EA). In this narrative review we wish to showcase that many of the negative outcomes of training-overload (with, or without an OTS diagnosis) may be primarily due to misdiagnosed under-fueling, or RED-S, via low EA and/or low CHO availability. Accordingly, we undertook an analysis of training-overload/OTS type studies that have also collected and analyzed for energy intake (EI), CHO, exercise energy expenditure (EEE) and/or EA. Eighteen of the 21 studies (86%) that met our criteria showed indications of an EA decrease or difference between two cohorts within a given study (n = 14 studies) or CHO availability decrease (n = 4 studies) during the training-overload/OTS period, resulting in both training-overload/OTS and RED-S symptom outcomes compared to control conditions. Furthermore, we demonstrate significantly similar symptom overlaps across much of the OTS (n = 57 studies) and RED-S/Female Athlete Triad (n = 88 studies) literature. It is important to note that the prevention of under-recovery is multi-factorial, but many aspects are based around EA and CHO availability. Herein we have demonstrated that OTS and RED-S have many shared pathways, symptoms, and diagnostic complexities. Substantial attention is required to increase the knowledge and awareness of RED-S, and to enhance the diagnostic accuracy of both OTS and RED-S, to allow clinicians to more accurately exclude LEA/RED-S from OTS diagnoses.
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http://dx.doi.org/10.1007/s40279-021-01491-0DOI Listing
June 2021

The Effects of an Acute "Train-Low" Nutritional Protocol on Markers of Recovery Optimization in Endurance-Trained Male Athletes.

Int J Sports Physiol Perform 2021 May 27:1-13. Epub 2021 May 27.

Purpose: This study aimed to determine the effects of an acute "train-low" nutritional protocol on markers of recovery optimization compared to standard recovery nutrition protocol.

Methods: After completing a 2-hour high-intensity interval running protocol, 8 male endurance athletes consumed a standard dairy milk recovery beverage (CHO; 1.2 g/kg body mass [BM] of carbohydrate and 0.4 g/kg BM of protein) and a low-carbohydrate (L-CHO; isovolumetric with 0.35 g/kg BM of carbohydrate and 0.5 g/kg BM of protein) dairy milk beverage in a double-blind randomized crossover design. Venous blood and breath samples, nude BM, body water, and gastrointestinal symptom measurements were collected preexercise and during recovery. Muscle biopsy was performed at 0 hour and 2 hours of recovery. Participants returned to the laboratory the following morning to measure energy substrate oxidation and perform a 1-hour distance test.

Results: The exercise protocol resulted in depletion of muscle glycogen stores (250 mmol/kg dry weight) and mild body-water losses (BM loss = 1.8%). Neither recovery beverage replenished muscle glycogen stores (279 mmol/kg dry weight) or prevented a decrease in bacterially stimulated neutrophil function (-21%). Both recovery beverages increased phosphorylation of mTORSer2448 (main effect of time = P < .001) and returned hydration status to baseline. A greater fold increase in p-GSK-3βSer9/total-GSK-3β occurred on CHO (P = .012). Blood glucose (P = .005) and insulin (P = .012) responses were significantly greater on CHO (618 mmol/L per 2 h and 3507 μIU/mL per 2 h, respectively) compared to L-CHO (559 mmol/L per 2 h and 1147 μIU/mL per 2 h, respectively). Rates of total fat oxidation were greater on CHO, but performance was not affected.

Conclusion: A lower-carbohydrate recovery beverage consumed after exercise in a "train-low" nutritional protocol does not negatively impact recovery optimization outcomes.
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http://dx.doi.org/10.1123/ijspp.2020-0847DOI Listing
May 2021

ACSM Expert Consensus Statement on Weight Loss in Weight-Category Sports.

Curr Sports Med Rep 2021 Apr;20(4):199-217

Department of Kinesiology and Nutrition, University of Illinois at Chicago, Chicago, IL.

Abstract: Weight-category sports are defined by the requirement of a weigh-in before competition to provide performance equity and reduced injury risks by eliminating size discrepancies. Athletes in these sports try to gain a theoretical advantage by competing in weight divisions that are lower than their day-to-day body mass (BM), using a combination of chronic strategies (body-fat losses) and acute manipulations over a period of hours to days before weigh-in ("making weight"). Strategies to support safer practices include minimal competition weight classification based on preseason body composition, reductions in the period between weigh-in and competition, and prohibition of unhealthy weight loss techniques. At an individual level, expert guidance by a sports nutrition professional can help an athlete to establish a pragmatic and long-term approach to BM management, recognizing the nuances of their sport, to achieve favorable outcomes for both health and performance.
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http://dx.doi.org/10.1249/JSR.0000000000000831DOI Listing
April 2021

Assessing Overall Exercise Recovery Processes Using Carbohydrate and Carbohydrate-Protein Containing Recovery Beverages.

Front Physiol 2021 4;12:628863. Epub 2021 Feb 4.

Department of Nutrition and Dietetics, Monash University, Notting Hill, VIC, Australia.

We compared the impact of two different, but commonly consumed, beverages on integrative markers of exercise recovery following a 2 h high intensity interval exercise (i.e., running 70-80% O intervals and interspersed with plyometric jumps). Participants ( = 11 males, = 6 females) consumed a chocolate flavored dairy milk beverage (CM: 1.2 g carbohydrate/kg BM and 0.4 g protein/kg BM) or a carbohydrate-electrolyte beverage (CEB: isovolumetric with 0.76 g carbohydrate/kg BM) after exercise, in a randomized-crossover design. The recovery beverages were provided in three equal boluses over a 30 min period commencing 1 h post-exercise. Muscle biopsies were performed at 0 h and 2 h in recovery. Venous blood samples, nude BM and total body water were collected before and at 0, 2, and 4 h recovery. Gastrointestinal symptoms and breath hydrogen (H) were collected before exercise and every 30 min during recovery. The following morning, participants returned for performance assessment. In recovery, breath H reached clinical relevance of >10 ppm following consumption of both beverages, in adjunct with high incidence of gastrointestinal symptoms (70%), but modest severity. Blood glucose response was greater on CEB vs. CM ( < 0.01). Insulin response was greater on CM compared with CEB ( < 0.01). lipopolysaccharide stimulated neutrophil function reduced on both beverages (49%). p-GSK-3β/total-GSK-3β was greater on CM compared with CEB ( = 0.037); however, neither beverage achieved net muscle glycogen re-storage. Phosphorylation of mTOR was greater on CM than CEB ( < 0.001). Fluid retention was lower ( = 0.038) on CEB (74.3%) compared with CM (82.1%). Physiological and performance outcomes on the following day did not differ between trials. Interconnected recovery optimization markers appear to respond differently to the nutrient composition of recovery nutrition, albeit subtly and with individual variation. The present findings expand on recovery nutrition strategies to target functionality and patency of the gastrointestinal tract as a prerequisite to assimilation of recovery nutrition, as well as restoration of immunocompetency.
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http://dx.doi.org/10.3389/fphys.2021.628863DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7890126PMC
February 2021

Does the Nutritional Composition of Dairy Milk Based Recovery Beverages Influence Post-exercise Gastrointestinal and Immune Status, and Subsequent Markers of Recovery Optimisation in Response to High Intensity Interval Exercise?

Front Nutr 2020 14;7:622270. Epub 2021 Jan 14.

Department of Nutrition Dietetics & Food, Monash University, Notting Hill, VIC, Australia.

This study aimed to determine the effects of flavored dairy milk based recovery beverages of different nutrition compositions on markers of gastrointestinal and immune status, and subsequent recovery optimisation markers. After completing 2 h high intensity interval running, participants ( = 9) consumed a whole food dairy milk recovery beverage (CM, 1.2 g/kg body mass (BM) carbohydrate and 0.4 g/kg BM protein) or a dairy milk based supplement beverage (MBSB, 2.2 g/kg BM carbohydrate and 0.8 g/kg BM protein) in a randomized crossover design. Venous blood samples, body mass, body water, and breath samples were collected, and gastrointestinal symptoms (GIS) were measured, pre- and post-exercise, and during recovery. Muscle biopsies were performed at 0 and 2 h of recovery. The following morning, participants returned to the laboratory to assess performance outcomes. In the recovery period, carbohydrate malabsorption (breath H peak: 49 . 24 ppm) occurred on MBSB compared to CM, with a trend toward greater gut discomfort. No difference in gastrointestinal integrity (i.e., I-FABP and sCD14) or immune response (i.e., circulating leukocyte trafficking, bacterially-stimulated neutrophil degranulation, and systemic inflammatory profile) markers were observed between CM and MBSB. Neither trial achieved a positive rate of muscle glycogen resynthesis [-25.8 (35.5) mmol/kg dw/h]. Both trials increased phosphorylation of intramuscular signaling proteins. Greater fluid retention (total body water: 86.9 . 81.9%) occurred on MBSB compared to CM. Performance outcomes did not differ between trials. The greater nutrient composition of MBSB induced greater gastrointestinal functional disturbance, did not prevent the post-exercise reduction in neutrophil function, and did not support greater overall acute recovery.
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http://dx.doi.org/10.3389/fnut.2020.622270DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7840831PMC
January 2021

Sustained Exposure to High Carbohydrate Availability Does Not Influence Iron-Regulatory Responses in Elite Endurance Athletes.

Int J Sport Nutr Exerc Metab 2021 Dec 31;31(2):101-108. Epub 2021 Dec 31.

Australian Institute of Sport.

This study implemented a 2-week high carbohydrate (CHO) diet intended to maximize CHO oxidation rates and examined the iron-regulatory response to a 26-km race walking effort. Twenty international-level, male race walkers were assigned to either a novel high CHO diet (MAX = 10 g/kg body mass CHO daily) inclusive of gut-training strategies, or a moderate CHO control diet (CON = 6 g/kg body mass CHO daily) for a 2-week training period. The athletes completed a 26-km race walking test protocol before and after the dietary intervention. Venous blood samples were collected pre-, post-, and 3 hr postexercise and measured for serum ferritin, interleukin-6, and hepcidin-25 concentrations. Similar decreases in serum ferritin (17-23%) occurred postintervention in MAX and CON. At the baseline, CON had a greater postexercise increase in interleukin-6 levels after 26 km of walking (20.1-fold, 95% CI [9.2, 35.7]) compared with MAX (10.2-fold, 95% CI [3.7, 18.7]). A similar finding was evident for hepcidin levels 3 hr postexercise (CON = 10.8-fold, 95% CI [4.8, 21.2]; MAX = 8.8-fold, 95% CI [3.9, 16.4]). Postintervention, there were no substantial differences in the interleukin-6 response (CON = 13.6-fold, 95% CI [9.2, 20.5]; MAX = 11.2-fold, 95% CI [6.5, 21.3]) or hepcidin levels (CON = 7.1-fold, 95% CI [2.1, 15.4]; MAX = 6.3-fold, 95% CI [1.8, 14.6]) between the dietary groups. Higher resting serum ferritin (p = .004) and hotter trial ambient temperatures (p = .014) were associated with greater hepcidin levels 3 hr postexercise. Very high CHO diets employed by endurance athletes to increase CHO oxidation have little impact on iron regulation in elite athletes. It appears that variations in serum ferritin concentration and ambient temperature, rather than dietary CHO, are associated with increased hepcidin concentrations 3 hr postexercise.
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http://dx.doi.org/10.1123/ijsnem.2020-0224DOI Listing
December 2021

Iron Metabolism: Interactions with Energy and Carbohydrate Availability.

Nutrients 2020 Nov 30;12(12). Epub 2020 Nov 30.

School of Human Sciences (Exercise and Sport Science), University of Western Australia, Crawley, WA 6009, Australia.

The provision or restriction of select nutrients in an athlete's diet can elicit a variety of changes in fuel utilization, training adaptation, and performance outcomes. Furthermore, nutrient availability can also influence athlete health, with one key system of interest being iron metabolism. The aim of this review was to synthesize the current evidence examining the impact of dietary manipulations on the iron regulatory response to exercise. Specifically, we assessed the impact of both acute and chronic carbohydrate (CHO) restriction on iron metabolism, with relevance to contemporary sports nutrition approaches, including models of periodized CHO availability and ketogenic low CHO high fat diets. Additionally, we reviewed the current evidence linking poor iron status and altered hepcidin activity with low energy availability in athletes. A cohesive understanding of these interactions guides nutritional recommendations for athletes struggling to maintain healthy iron stores, and highlights future directions and knowledge gaps specific to elite athletes.
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http://dx.doi.org/10.3390/nu12123692DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7761418PMC
November 2020

Quinine Ingestion During the Latter Stages of a 3,000-m Time Trial Fails to Improve Cycling Performance.

Int J Sport Nutr Exerc Metab 2020 Dec 1;31(1):9-12. Epub 2020 Dec 1.

Australian Institute of Sport.

The ingestion of quinine, a bitter tastant, improves short-term (30 s) cycling performance, but it is unclear whether this effect can be integrated into the last effort of a longer race. The purpose of this study was to determine whether midtrial quinine ingestion improves 3,000-m cycling time-trial (TT) performance. Following three familiarization TTs, 12 well-trained male cyclists (mean ± SD: mass = 76.6 ± 9.2 kg, maximal aerobic power = 390 ± 50 W, maximal oxygen uptake = 4.7 ± 0.6 L/min) performed four experimental 3,000-m TTs on consecutive days. This double-blind, crossover design study had four randomized and counterbalanced conditions: (a) Quinine 1 (25-ml solution, 2 mM of quinine); (b) Quinine 2, replicate of Quinine 1; (c) a 25-ml sweet-tasting no-carbohydrate solution (Placebo); and (d) 25 ml of water (Control) consumed at the 1,850-m point of the TT. The participants completed a series of perceptual scales at the start and completion of all TTs, and the power output was monitored continuously throughout all trials. The power output for the last 1,000 m for all four conditions was similar: mean ± SD: Quinine 1 = 360 ± 63 W, Quinine 2 = 367 ± 63 W, Placebo = 364 ± 64 W, and Control = 367 ± 58 W. There were also no differences in the 3,000-m TT power output between conditions. The small perceptual differences between trials at specific 150-m splits were not explained by quinine intake. Ingesting 2 mM of quinine during the last stage of a 3,000-m TT did not improve cycling performance.
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http://dx.doi.org/10.1123/ijsnem.2020-0265DOI Listing
December 2020

Prevalence of impaired physiological function consistent with Relative Energy Deficiency in Sport (RED-S): an Australian elite and pre-elite cohort.

Br J Sports Med 2021 Jan 16;55(1):38-45. Epub 2020 Nov 16.

Research Institute for Sport and Exercise, University of Canberra, Bruce, Australian Capital Territory, Australia.

Objectives: Athlete health, training continuity and performance can be impeded as a result of Relative Energy Deficiency in Sport (RED-S). Here we report the point prevalence of symptoms described by the RED-S model in a mixed-sport cohort of Australian female athletes.

Methods: Elite and pre-elite female athletes (n=112) from eight sports completed validated questionnaires and underwent clinical assessment to assess the point prevalence of RED-S symptoms. Questionnaires included the Depression, Anxiety and Stress Questionnaire (DASS-21), Generalized Anxiety Disorder (GAD-7), Center for Epidemiological Studies Depression Scale (CES-D), SCOFF questionnaire for disordered eating, Low Energy Availability in Females Questionnaire (LEAF-Q), and a custom questionnaire on injury and illness. Clinical assessment comprised resting metabolic rate (RMR) assessment, dual-energy X-ray absorptiometry-derived body composition and bone mineral density, venous and capillary blood samples, and the Mini International Neuropsychiatric Interview (MINI 7.0.2). Descriptive prevalence statistics are presented.

Results: Almost all (80%) participants (age 19 (range 15-32) years; mass 69.5±10.3 kg; body fat 23.1%±5.0%) demonstrated at least one symptom consistent with RED-S, with 37% exhibiting between two and three symptoms. One participant demonstrated five symptoms. Impaired function of the immunological (28%, n27), haematological (31%, n33) and gastrointestinal (47%, n51) systems were most prevalent. A moderate to high (11%-55%) prevalence of risk of low energy availability was identified via RMR and LEAF-Q, and identified mental illnesses were prevalent in one-third of the assessed cohort.

Conclusion: Symptoms described by the RED-S model were prevalent in this cohort, supporting the need for improved awareness, monitoring and management of these symptoms in this population.
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http://dx.doi.org/10.1136/bjsports-2019-101517DOI Listing
January 2021

Athlete health and safety at large sporting events: the development of consensus-driven guidelines.

Br J Sports Med 2021 Feb 12;55(4):191-197. Epub 2020 Nov 12.

Medical and Scientific Commission-Games Group Anaesthesiologist and Emergency Pre-Hospital Care Consultant, International Olympic Committee, Lausanne, Vaud, Switzerland.

All sport events have inherent injury and illness risks for participants. Healthcare services for sport events should be planned and delivered to mitigate these risks which is the ethical responsibility of all sport event organisers. The objective of this paper was to develop consensus-driven guidelines describing the basic standards of services necessary to protect athlete health and safety during large sporting events. By using the Knowledge Translation Scheme Framework, a gap in International Federation healthcare programming for sport events was identified. Event healthcare content areas were determined through a narrative review of the scientific literature. Content experts were systematically identified. Following a literature search, an iterative consensus process was undertaken. The outcome document was written by the knowledge translation expert writing group, with the assistance of a focus group consisting of a cohort of International Federation Medical Chairpersons. Athletes were recruited to review and provide comment. The Healthcare Guidelines for International Federation Events document was developed including content-related to (i) pre-event planning (eg, sport medical risk assessment, public health requirements, environmental considerations), (ii) event safety (eg, venue medical services, emergency action plan, emergency transport, safety and security) and (iii) additional considerations (eg, event health research, spectator medical services). We developed a generic standardised template guide to facilitate the planning and delivery of medical services at international sport events. The organisers of medical services should adapt, evaluate and modify this guide to meet the sport-specific local context.
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http://dx.doi.org/10.1136/bjsports-2020-102771DOI Listing
February 2021

UEFA expert group statement on nutrition in elite football. Current evidence to inform practical recommendations and guide future research.

Br J Sports Med 2021 Apr 23;55(8):416. Epub 2020 Oct 23.

Medical & Anti-doping, UEFA, Nyon, Switzerland.

Football is a global game which is constantly evolving, showing substantial increases in physical and technical demands. Nutrition plays a valuable integrated role in optimising performance of elite players during training and match-play, and maintaining their overall health throughout the season. An evidence-based approach to nutrition emphasising, a 'food first' philosophy (ie, food over supplements), is fundamental to ensure effective player support. This requires relevant scientific evidence to be applied according to the constraints of what is practical and feasible in the football setting. The science underpinning sports nutrition is evolving fast, and practitioners must be alert to new developments. In response to these developments, the Union of European Football Associations (UEFA) has gathered experts in applied sports nutrition research as well as practitioners working with elite football clubs and national associations/federations to issue an expert statement on a range of topics relevant to elite football nutrition: (1) match day nutrition, (2) training day nutrition, (3) body composition, (4) stressful environments and travel, (5) cultural diversity and dietary considerations, (6) dietary supplements, (7) rehabilitation, (8) referees and (9) junior high-level players. The expert group provide a narrative synthesis of the scientific background relating to these topics based on their knowledge and experience of the scientific research literature, as well as practical experience of applying knowledge within an elite sports setting. Our intention is to provide readers with content to help drive their own practical recommendations. In addition, to provide guidance to applied researchers where to focus future efforts.
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http://dx.doi.org/10.1136/bjsports-2019-101961DOI Listing
April 2021

Chronic pantothenic acid supplementation does not affect muscle coenzyme A content or cycling performance.

Appl Physiol Nutr Metab 2021 Mar 19;46(3):280-283. Epub 2020 Oct 19.

Exercise and Nutrition Research Program, Mary MacKillop Institute for Health Research, Australian Catholic University, Melbourne, VIC 3000, Australia.

This study determined if supplementation with pantothenic acid (PA) for 16 weeks could increase skeletal muscle coenzyme A (CoASH) content and exercise performance. Trained male cyclists ( = 14) were matched into control or PA (6 g·day) groups. At 0, 4, 8, and 16 weeks, subjects performed an incremental time to exhaustion cycle with muscle biopsies taken prior to and following exercise. Prolonged PA supplementation did not change skeletal muscle CoASH and acetyl-CoA contents or exercise performance. Supplementation with pantothenic acid for 16 weeks had no effect on skeletal muscle CoASH and acetyl-CoA content or exercise performance in trained male cyclists.
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http://dx.doi.org/10.1139/apnm-2020-0692DOI Listing
March 2021

Acute Ketogenic Diet and Ketone Ester Supplementation Impairs Race Walk Performance.

Med Sci Sports Exerc 2021 04;53(4):776-784

Griffith Sports Physiology and Performance, Griffith University, Gold Coast, QLD, AUSTRALIA.

Purpose: This study aimed to determine if LCHF and ketone ester (KE) supplementation can synergistically alter exercise metabolism and improve performance.

Methods: Elite race walkers (n = 18, 15 males and 3 females; V˙O2peak, 62 ± 6 mL·min-1·kg-1) undertook a four-stage exercise economy test and real-life 10,000-m race before and after a 5-d isoenergetic high-CHO (HCHO, ~60%-65% fat; CHO, 20% fat; n = 9) or LCHF (75%-80% fat, <50 g·d-1 CHO, n = 9) diet. The LCHF group performed additional economy tests before and after diet after supplementation with 573 mg·kg-1 body mass KE (HVMN; HVMN Inc., San Francisco, CA), which was also consumed for race 2.

Results: The oxygen cost of exercise (relative V˙O2, mL·min-1·kg-1) increased across all four stages after LCHF (P < 0.005). This occurred in association with increased fat oxidation rates, with a reciprocal decrease in CHO oxidation (P < 0.001). Substrate utilization in the HCHO group remained unaltered. The consumption of KE before the LCHF diet increased circulating KB (P < 0.05), peaking at 3.2 ± 0.6 mM, but did not alter V˙O2 or RER. LCHF diet elevated resting circulating KB (0.3 ± 0.1 vs 0.1 ± 0.1 mM), but concentrations after supplementation did not differ from the earlier ketone trial. Critically, race performance was impaired by ~6% (P < 0.0001) relative to baseline in the LCHF group but was unaltered in HCHO.

Conclusion: Despite elevating endogenous KB production, an LCHF diet does not augment the metabolic responses to KE supplementation and negatively affects race performance.
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http://dx.doi.org/10.1249/MSS.0000000000002517DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7969177PMC
April 2021

Carbohydrate Hydrogel Products Do Not Improve Performance or Gastrointestinal Distress During Moderate-Intensity Endurance Exercise.

Int J Sport Nutr Exerc Metab 2020 Jul 23;30(5):305-314. Epub 2020 Jul 23.

Australian Catholic University.

The benefits of ingesting exogenous carbohydrate (CHO) during prolonged exercise performance are well established. A recent food technology innovation has seen sodium alginate and pectin included in solutions of multiple transportable CHO, to encapsulate them at pH levels found in the stomach. Marketing claims include enhanced gastric emptying and delivery of CHO to the muscle with less gastrointestinal distress, leading to better sports performance. Emerging literature around such claims was identified by searching electronic databases; inclusion criteria were randomized controlled trials investigating metabolic and/or exercise performance parameters during endurance exercise >1 hr, with CHO hydrogels versus traditional CHO fluids and/or noncaloric hydrogels. Limitations associated with the heterogeneity of exercise protocols and control comparisons are noted. To date, improvements in exercise performance/capacity have not been clearly demonstrated with ingestion of CHO hydrogels above traditional CHO fluids. Studies utilizing isotopic tracers demonstrate similar rates of exogenous CHO oxidation, and subjective ratings of gastrointestinal distress do not appear to be different. Overall, data do not support any metabolic or performance advantages to exogenous CHO delivery in hydrogel form over traditional CHO preparations; although, one study demonstrates a possible glycogen sparing effect. The authors note that the current literature has largely failed to investigate the conditions under which maximal CHO availability is needed; high-performance athletes undertaking prolonged events at high relative and absolute exercise intensities. Although investigations are needed to better target the testimonials provided about CHO hydrogels, current evidence suggests that they are similar in outcome and a benefit to traditional CHO sources.
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http://dx.doi.org/10.1123/ijsnem.2020-0102DOI Listing
July 2020

Adaptation to a low carbohydrate high fat diet is rapid but impairs endurance exercise metabolism and performance despite enhanced glycogen availability.

J Physiol 2021 02 19;599(3):771-790. Epub 2020 Aug 19.

Australian Institute of Sport, Canberra, Australia.

Key Points: Brief (5-6 days) adaptation to a low carbohydrate high fat diet in elite athletes increased exercise fat oxidation to rates previously observed with medium (3-4 weeks) or chronic (>12 months) adherence to this diet, with metabolic changes being washed out in a similar time frame. Increased fat utilisation during exercise was associated with a 5-8% increase in oxygen cost at speeds related to Olympic Programme races. Acute restoration of endogenous carbohydrate (CHO) availability (24 h high CHO diet, pre-race CHO) only partially restored substrate utilisation during a race warm-up. Fat oxidation continued to be elevated above baseline values although it was lower than achieved by 5-6 days' keto adaptation; CHO oxidation only reached 61% and 78% of values previously seen at exercise intensities related to race events. Acute restoration of CHO availability failed to overturn the impairment of high-intensity endurance performance previously associated with low carbohydrate high fat adaptation, potentially due to the blunted capacity for CHO oxidation.

Abstract: We investigated substrate utilisation during exercise after brief (5-6 days) adaptation to a ketogenic low-carbohydrate (CHO), high-fat (LCHF) diet and similar washout period. Thirteen world-class male race walkers completed economy testing, 25 km training and a 10,000 m race (Baseline), with high CHO availability (HCHO), repeating this (Adaptation) after 5-6 days' LCHF (n = 7; CHO: <50 g day , protein: 2.2 g kg day ; 80% fat) or HCHO (n = 6; CHO: 9.7 g kg day ; protein: 2.2 g kg day ) diet. An Adaptation race was undertaken after 24 h HCHO and pre-race CHO (2 g kg ) diet, identical to the Baseline race. Substantial (>200%) increases in exercise fat oxidation occurred in the LCHF Adaptation economy and 25 km tests, reaching mean rates of ∼1.43 g min . However, relative (ml min  kg ) was higher (P < 0.0001), by ∼8% and 5% at speeds related to 50 km and 20 km events. During Adaptation race warm-up in the LCHF group, rates of fat and CHO oxidation at these speeds were decreased and increased, respectively (P < 0.001), compared with the previous day, but were not restored to Baseline values. Performance changes differed between groups (P = 0.009), with all HCHO athletes improving in the Adaptation race (5.7 (5.6)%), while 6/7 LCHF athletes were slower (2.2 (3.4)%). Substrate utilisation returned to Baseline values after 5-6 days of HCHO diet. In summary, robust changes in exercise substrate use occurred in 5-6 days of extreme changes in CHO intake. However, adaptation to a LCHF diet plus acute restoration of endogenous CHO availability failed to restore high-intensity endurance performance, with CHO oxidation rates remaining blunted.
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http://dx.doi.org/10.1113/JP280221DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7891450PMC
February 2021

The Australian Institute of Sport (AIS) and National Eating Disorders Collaboration (NEDC) position statement on disordered eating in high performance sport.

Br J Sports Med 2020 Nov 13;54(21):1247-1258. Epub 2020 Jul 13.

AIS Medicine, Australian Institute of Sport, Canberra, Australian Capital Territory, Australia

Identification, evaluation and management of disordered eating (DE) is complex. DE exists along the spectrum from optimised nutrition through to clinical eating disorders (EDs). Individual athletes can move back and forth along the spectrum of eating behaviour at any point in time over their career and within different stages of a training cycle. Athletes are more likely to present with DE than a clinical ED. Overall, there is a higher prevalence of DE and EDs in athletes compared with non-athletes. Additionally, athletes participating in aesthetic, gravitational and weight-class sports are at higher risk of DE and EDs than those in sports without these characteristics. The evaluation and management of DE requires a cohesive team of professional practitioners consisting of, at minimum, a doctor, a sports dietitian and a psychologist, termed within this statement as the core multidisciplinary team. The Australian Institute of Sport and the National Eating Disorders Collaboration have collaborated to provide this position statement, containing guidelines for athletes, coaches, support staff, clinicians and sporting organisations. The guidelines support the prevention and early identification of DE, and promote timely intervention to optimise nutrition for performance in a safe, supported, purposeful and individualised manner. This position statement is a call to action to all involved in sport to be aware of poor self-image and poor body image among athletes. The practical recommendations should guide the clinical management of DE in high performance sport.
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http://dx.doi.org/10.1136/bjsports-2019-101813DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7588409PMC
November 2020

Crisis of confidence averted: Impairment of exercise economy and performance in elite race walkers by ketogenic low carbohydrate, high fat (LCHF) diet is reproducible.

PLoS One 2020 4;15(6):e0234027. Epub 2020 Jun 4.

Australian Institute of Sport, Canberra, Australia.

Introduction: We repeated our study of intensified training on a ketogenic low-carbohydrate (CHO), high-fat diet (LCHF) in world-class endurance athletes, with further investigation of a "carryover" effect on performance after restoring CHO availability in comparison to high or periodised CHO diets.

Methods: After Baseline testing (10,000 m IAAF-sanctioned race, aerobic capacity and submaximal walking economy) elite male and female race walkers undertook 25 d supervised training and repeat testing (Adapt) on energy-matched diets: High CHO availability (8.6 g∙kg-1∙d-1 CHO, 2.1 g∙kg-1∙d-1 protein; 1.2 g∙kg-1∙d-1 fat) including CHO before/during/after workouts (HCHO, n = 8): similar macronutrient intake periodised within/between days to manipulate low and high CHO availability at various workouts (PCHO, n = 8); and LCHF (<50 g∙d-1 CHO; 78% energy as fat; 2.1 g∙kg-1∙d-1 protein; n = 10). After Adapt, all athletes resumed HCHO for 2.5 wk before a cohort (n = 19) completed a 20 km race.

Results: All groups increased VO2peak (ml∙kg-1∙min-1) at Adapt (p = 0.02, 95%CI: [0.35-2.74]). LCHF markedly increased whole-body fat oxidation (from 0.6 g∙min-1 to 1.3 g∙min-1), but also the oxygen cost of walking at race-relevant velocities. Differences in 10,000 m performance were clear and meaningful: HCHO improved by 4.8% or 134 s (95% CI: [207 to 62 s]; p < 0.001), with a trend for a faster time (2.2%, 61 s [-18 to +144 s]; p = 0.09) in PCHO. LCHF were slower by 2.3%, -86 s ([-18 to -144 s]; p < 0.001), with no evidence of superior "rebound" performance over 20 km after 2.5 wk of HCHO restoration and taper.

Conclusion: Our previous findings of impaired exercise economy and performance of sustained high-intensity race walking following keto-adaptation in elite competitors were repeated. Furthermore, there was no detectable benefit from undertaking an LCHF intervention as a periodised strategy before a 2.5-wk race preparation/taper with high CHO availability.

Trial Registration: Australia New Zealand Clinical Trial Registry: ACTRN12619000794101.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0234027PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7272074PMC
August 2020

The Challenge of Maintaining Metabolic Health During a Global Pandemic.

Sports Med 2020 07;50(7):1233-1241

Exercise and Nutrition Research Program, The Mary Mackillop Institute for Health Research, Australian Catholic University, Level 5, 215 Spring Street, Melbourne, VIC, 3000, Australia.

The ongoing global pandemic brought on by the spread of the novel coronavirus SARS-CoV-2 is having profound effects on human health and well-being. With no viable vaccine presently available and the virus being rapidly transmitted, governments and national health authorities have acted swiftly, recommending 'lockdown' policies and/or various levels of social restriction/isolation to attenuate the rate of infection. An immediate consequence of these strategies is reduced exposure to daylight, which can result in marked changes in patterns of daily living such as the timing of meals, and sleep. These disruptions to circadian biology have severe cardiometabolic health consequences for susceptible individuals. We discuss the consequences of reductions in patterns of daily physical activity and the resulting energy imbalance induced by periods of isolation, along with several home-based strategies to maintain cardiometabolic health in the forthcoming months.
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http://dx.doi.org/10.1007/s40279-020-01295-8DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7245641PMC
July 2020

Ketogenic low-CHO, high-fat diet: the future of elite endurance sport?

Authors:
Louise M Burke

J Physiol 2021 02 10;599(3):819-843. Epub 2020 Jun 10.

Australian Institute of Sport, Canberra, 2616, Australia.

The ability of ketogenic low-carbohydrate (CHO) high-fat (K-LCHF) diets to enhance muscle fat oxidation has led to claims that it is the 'future of elite endurance sport'. There is robust evidence that substantial increases in fat oxidation occur, even in elite athletes, within 3-4 weeks and possibly 5-10 days of adherence to a K-LCHF diet. Retooling of the muscle can double exercise fat use to ∼1.5 g min , with the intensity of maximal rates of oxidation shifting from ∼45% to ∼70% of maximal aerobic capacity. Reciprocal reductions in CHO oxidation during exercise are clear, but current evidence to support the hypothesis of the normalization of muscle glycogen content with longer-term adaptation is weak. Importantly, keto-adaptation may impair the muscle's ability to use glycogen for oxidative fates, compromising the use of a more economical energy source when the oxygen supply becomes limiting and, thus, the performance of higher-intensity exercise (>80% maximal aerobic capacity). Even with moderate intensity exercise, individual responsiveness to K-LCHF is varied, with extremes at both ends of the performance spectrum. Periodisation of K-LCHF with high CHO availability might offer opportunities to restore capacity for higher-intensity exercise, but investigations of various models have failed to find a benefit over dietary approaches based on current sports nutrition guidelines. Endurance athletes who are contemplating the use of K-LCHF should undertake an audit of event characteristics and personal experiences to balance the risk of impaired performance of higher-intensity exercise with the likelihood of an unavoidable depletion of carbohydrate stores.
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http://dx.doi.org/10.1113/JP278928DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7891323PMC
February 2021

Key viral immune genes and pathways identify elite athletes with URS.

Exerc Immunol Rev 2020 ;26:56-78

School of Medical Science and Menzies Health Institute QLD, Griffith University, Southport, QLD, Australia, Griffith University, QLD, Australia.

Purpose: Habitual intense exercise may increase the incidence of upper respiratory symptoms (URS) in elite athletes. This study investigated whether immune gene expression could identify gene markers that discriminate athletes with a higher prevalence of URS.

Methods: This cross-sectional analysis of elite Australian athletes from various sports investigated whether athletes retrospectively reporting URS for two days or more in a month (n=38), had an altered immune gene expression profile compared with asymptomatic athletes (n=33). Peripheral blood samples were collected during Olympic selection events with corresponding URS data collected for the one-month period before sampling. Digital immune gene expression analysis was undertaken using the NanoString PanCancer Immune Profiling panel.

Results: Fifty immune genes were differentially expressed between the groups (p<0.05) and approximately 78% of these genes were more highly expressed in athletes reporting URS. Many of these genes were interferon-stimulated genes or genes involved in the Jak/Stat signalling pathway. Only interferon alpha inducible protein 27 (IFI27), an interferon stimulated gene involved in viral response, remained significantly higher in athletes reporting URS (log2 fold-difference=2.49, odds ratio 1.02 per unit increase; p<0.01) post-adjustment and discriminated athletes reporting URS from asymptomatic athletes with 78% accuracy.

Conclusions: Expression of IFI27 could differentiate athletes reporting URS from asymptomatic athletes, a gene that is upregulated in the immune response to viral infection. Upregulation of viral signalling pathways provides novel information on the potential aetiology of URS in elite Olympic athletes.
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March 2020

A Short-Term Ketogenic Diet Impairs Markers of Bone Health in Response to Exercise.

Front Endocrinol (Lausanne) 2019 21;10:880. Epub 2020 Jan 21.

Division of Sports Medicine, Boston Children's Hospital, Boston, MA, United States.

To investigate diet-exercise interactions related to bone markers in elite endurance athletes after a 3.5-week ketogenic low-carbohydrate, high-fat (LCHF) diet and subsequent restoration of carbohydrate (CHO) feeding. World-class race walkers (25 male, 5 female) completed 3.5-weeks of energy-matched (220 kJ·kg·d) high CHO (HCHO; 8.6 g·kg·d CHO, 2.1 g·kg·d protein, 1.2 g·kg·d fat) or LCHF (0.5 g·kg·d CHO, 2.1 g·kg·d protein, 75-80% of energy from fat) diet followed by acute CHO restoration. Serum markers of bone breakdown (cross-linked C-terminal telopeptide of type I collagen, CTX), formation (procollagen 1 N-terminal propeptide, P1NP) and metabolism (osteocalcin, OC) were assessed at rest (fasting and 2 h post meal) and after exercise (0 and 3 h) at Baseline, after the 3.5-week intervention (Adaptation) and after acute CHO feeding (Restoration). After Adaptation, LCHF increased fasting CTX concentrations above Baseline ( = 0.007, Cohen's = 0.69), while P1NP ( < 0.001, = 0.99) and OC ( < 0.001, = 1.39) levels decreased. Post-exercise, LCHF increased CTX concentrations above Baseline ( = 0.001, = 1.67) and above HCHO ( < 0.001, = 0.62), while P1NP ( < 0.001, = 0.85) and OC concentrations decreased ( < 0.001, = 0.99) during exercise. Exercise-related area under curve (AUC) for CTX was increased by LCHF after Adaptation ( = 0.001, = 1.52), with decreases in P1NP ( < 0.001, = 1.27) and OC ( < 0.001, = 2.0). CHO restoration recovered post-exercise CTX and CTX exercise-related AUC, while concentrations and exercise-related AUC for P1NP and OC remained suppressed for LCHF ( = 1.000 compared to Adaptation). Markers of bone modeling/remodeling were impaired after short-term LCHF diet, and only a marker of resorption recovered after acute CHO restoration. Long-term studies of the effects of LCHF on bone health are warranted.
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http://dx.doi.org/10.3389/fendo.2019.00880DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6985427PMC
January 2020

Core Temperature Responses to Elite Racewalking Competition.

Int J Sports Physiol Perform 2020 Jul 4;15(6):892-895. Epub 2020 Feb 4.

Purpose: The core temperature responses during exercise and effects of different cooling strategies on endurance performance under heat stress have been investigated in recreational athletes. This investigation aimed to determine peak rectal temperatures during elite racewalking competitions and to detail any cooling strategies used.

Methods: Rectal temperature was measured in 14 heat-adapted elite/preelite race walkers (9 females) via a telemetric capsule across 4 outdoor events, including the 2018 Commonwealth Games (race 1: 20 km, 25°C, 74% relative humidity [RH], n = 2) and 3 International Association of Athletics Federations-sanctioned 10-km events (race 2: 19°C, 34% RH, n = 2; race 3: 29°C, 47% RH, n = 14; and race 4: 23°C, 72% RH, n = 11). All athletes completed race 3, and a subsample completed the other events. Their use of cooling strategies and symptoms of heat illness were determined.

Results: Peak rectal temperatures >40°C were observed in all events. The highest rectal temperature observed during an event was 41.2°C. These high rectal temperatures were observed without concomitant heat illness, with the exception of cramping in one athlete during race 1. The rectal temperatures tended to reach a steady state in the second half of the 20-km event, but no steady state was observed in the 10-km events. The athletes used cooling strategies in race 1 only, implementing different combinations of cold-water immersion, ice-slurry ingestion, ice-towel application, ice-vest application, and facial water spraying.

Conclusions: Elite/preelite race walkers experience rectal temperatures >40°C during competition despite only moderate-warm conditions, and even when precooling and midcooling strategies are applied.
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http://dx.doi.org/10.1123/ijspp.2019-0397DOI Listing
July 2020
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