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Pulmonology 2021 Mar 2. Epub 2021 Mar 2.

Pulmonary Division and Sleep Disorders Center, University Hospital of Zurich, Raemistrasse 100, 8091 Zurich, Switzerland. Electronic address:

Background: High altitude pulmonary hypertension (HAPH), a chronic altitude related illness, is associated with hypoxemia, dyspnea and reduced exercise performance. We evaluated ECG and pulse wave-derived markers of cardiovascular risk in highlanders with HAPH (HAPH+) in comparison to healthy highlanders (HH) and lowlanders (LL) and the effects of hyperoxia.

Methods: We studied 34 HAPH+ and 54 HH at Aksay (3250m), and 34 LL at Bishkek (760m), Kyrgyzstan. Read More

Wilderness Environ Med 2021 Mar 9;32(1):36-40. Epub 2021 Jan 9.

Department of Medicine, Kilimanjaro Christian Medical Center, Moshi Kilimanjaro, United Republic of Tanzania.

Introduction: A significant number of climbers on Mount Kilimanjaro are affected by altitude-related disorders. The aim of this study was to determine the main causes of morbidity and mortality in a representative cohort of climbers based on local hospital records.

Methods: We conducted a 2-y retrospective chart review of all patients presenting to the main referral hospital in the region after a climb on Mount Kilimanjaro, including all relevant records and referrals for postmortem studies. Read More

J Sleep Res 2021 06 9;30(3):e13153. Epub 2020 Aug 9.

Department of Respiratory Medicine, Sleep Disorders Center, University Hospital of Zurich, Zurich, Switzerland.

High-altitude pulmonary hypertension (HAPH) is an altitude-related illness associated with hypoxaemia that may promote sympathetic excitation and prolongation of the QT interval. The present case-control study tests whether QT intervals, markers of malignant cardiac arrhythmias, are prolonged in highlanders with HAPH (HAPH+) compared to healthy highlanders (HH) and healthy lowlanders (LL). The mean pulmonary artery pressure (mPAP) was measured by echocardiography in 18 HAPH+ (mPAP, 34 mmHg) and 18 HH (mPAP, 23 mmHg) at 3,250 m, and 18 LL (mPAP, 18 mmHg) at 760 m, Kyrgyzstan (p < . Read More

Sleep Sci 2020 Apr-Jun;13(2):138-144

Hospital Britanico de Buenos Aires, Medicine Respiratory Unit - Buenos Aires - CABA - Argentina.

Objective: to compare mountaineers with and without asymptomatic sleep apnea (OSA) before the ascent and to study high altitude-related sleep disorders, its interaction with metabolic, neuroendocrine and immunological components.

Material And Methods: During an expedition to Mount Aconcagua, researchers assessed the respiratory polygraphy (RP), clinical condition and inflammatory parameters, and rhythm of cortisol secretion in mountaineers sleeping at different altitude camps.

Results: 8 athletes (4 women), 36 years old (25-51) participated. Read More

JAMA Netw Open 2020 06 1;3(6):e207940. Epub 2020 Jun 1.

Sleep Disorders Center, Department of Respiratory Medicine, University Hospital of Zurich, Zurich, Switzerland.

Importance: There are no established measures to prevent nocturnal breathing disturbances and other altitude-related adverse health effects (ARAHEs) among lowlanders with chronic obstructive pulmonary disease (COPD) traveling to high altitude.

Objective: To evaluate whether nocturnal oxygen therapy (NOT) prevents nocturnal hypoxemia and breathing disturbances during the first night of a stay at 2048 m and reduces the incidence of ARAHEs.

Design, Setting, And Participants: This randomized, placebo-controlled crossover trial was performed from January to October 2014 with 32 patients with COPD living below 800 m with forced expiratory volume in the first second of expiration (FEV1) between 30% and 80% predicted, pulse oximetry of at least 92%, not requiring oxygen therapy, and without history of sleep apnea. Read More

Ergonomics 2020 Oct 11;63(10):1281-1292. Epub 2020 Jun 11.

Laboratory of Exercise and Physical Activity Sciences, School of Physiotherapy, Universidad Finis Terrae, Santiago, Chile.

Mining activities expose workers to diverse working conditions, rotational shifts and high altitude-related hypobaric hypoxia. Separately, each condition has been reported having a negative impact on miners' health risk; however, the combination of both stressors has been poorly explored. The present study aimed to analyse the effects of exposure to rotational work shift (RWS) alone or in combination with high altitude-related chronic intermittent hypobaric hypoxia (CIHH) on cardiometabolic, physical activity and sleep quality related markers in copper miners from Los Pelambres mine in Chile. Read More

Brain Behav 2020 05 23;10(5):e01604. Epub 2020 Mar 23.

Neuroscience Research Lab, Department of Neurology, Postgraduate Institute of Medical Education and Research, Chandigarh, India.

Introduction: Incidence of high altitude-related sickness is increasing due to more number of people visiting the areas of high altitude which may result in life-threatening conditions including acute mountain sickness (AMS), high altitude pulmonary edema (HAPE), high altitude cerebral edema (HACE), and High-altitude pulmonary hypertension (HAPH). We hypothesized that an advanced yoga regimen may be beneficial in dealing with the physiology of acclimatization.

Methods: Anthropometric, Biochemical, and Psychological assessments were carried out in 48 participants before and after the advance meditation program (AMP) in the experimental group. Read More

Front Physiol 2019 28;10:1116. Epub 2019 Aug 28.

Department of Molecular and Cellular Therapeutics, Royal College of Surgeons in Ireland, Dublin, Ireland.

The first ascent of Mount Everest by Tenzing Norgay and Sir Edmund Hillary in 1953 brought global attention to the Sherpa people and human performance at altitude. The Sherpa inhabit the Khumbu Valley of Nepal, and are descendants of a population that has resided continuously on the Tibetan plateau for the past ∼25,000 to 40,000 years. The long exposure of the Sherpa to an inhospitable environment has driven genetic selection and produced distinct adaptive phenotypes. Read More

Int J Mol Sci 2019 Aug 22;20(17). Epub 2019 Aug 22.

Department of Anesthesiology, Perioperative and General Critical Care Medicine, University Hospital Salzburg, 5020 Salzburg, Austria.

Individuals ascending rapidly to altitudes >2500 m may develop symptoms of acute mountain sickness (AMS) within a few hours of arrival and/or high-altitude pulmonary edema (HAPE), which occurs typically during the first three days after reaching altitudes above 3000-3500 m. Both diseases have distinct pathologies, but both present with a pronounced decrease in oxygen saturation of hemoglobin in arterial blood (SO). This raises the question of mechanisms impairing the diffusion of oxygen (O) across the alveolar wall and whether the higher degree of hypoxemia is in causal relationship with developing the respective symptoms. Read More

High Alt Med Biol 2019 12 21;20(4):352-360. Epub 2019 Aug 21.

Department of Psychiatry, Psychotherapy and Psychosomatics, University Clinic for Psychiatry II, Innsbruck Medical University, Innsbruck, Austria.

Psychotic symptoms during exposure to high altitude (HA) have been linked to accidents or near accidents on the mountains. It is thus of great importance to directly identify psychotic symptoms in individuals who are exposed to HA quickly and reliably on the mountain, even in the absence of experienced medical personnel. Psychotic features at HA frequently include positive psychotic symptoms such as hallucinations, delusions, or disorganized thinking/speech. Read More

High Alt Med Biol 2019 09 25;20(3):207-214. Epub 2019 Jul 25.

Institute of Mountain Emergency Medicine, EURAC Research, Bolzano, Italy.

Psychiatric disorders have a high lifetime prevalence affecting about 30% of the global population. Not much is known about high altitude (HA) sojourns in individuals living with a psychiatric condition. This lack of scientific evidence contrasts with the anticipated increase in numbers of individuals with preexisting psychiatric conditions seeking medical advice on HA exposure. Read More

Addict Behav Rep 2019 Jun 18;9:100167. Epub 2019 Feb 18.

Department of Psychiatry, University of Utah School of Medicine, 383 Colorow Drive, Salt Lake City, UT, 84108, United States.

Objective: Prescription opioid misuse and fatal overdoses have increased significantly over the last two decades. Living at altitude has been linked to greater reward benefits of other drugs of abuse, and living at altitude may also exacerbate the respiratory depression linked to opioid use. Therefore, we examined the relationships between living at altitude, and prescription opioid misuse and fatal overdoses. Read More

Pract Neurol 2019 Oct 8;19(5):404-411. Epub 2019 Jun 8.

Internal Medicine, Kilimanjaro Christian Medical Centre, Moshi, United Republic of Tanzania.

Mountain climbers may develop specific illnesses that largely depend on the altitude reached and the rate of ascent. The popularity of travel to high altitude destinations, extreme tourist activities and mountain climbing means that neurologists in low-altitude countries are increasingly likely to encounter neurological problems and disorders in people exposed to high altitude. Additionally, they may have to advise patients with pre-existing neurological conditions on the risks of ascent to altitude. Read More

Respiration 2019;97(2):125-134. Epub 2018 Sep 28.

Department of Pulmonology, University Hospital Zurich, Zurich,

Background: Changes in pulmonary hemodynamics and cardiac function in patients with chronic obstructive pulmonary disease (COPD) traveling to altitude have not been assessed despite an increasing prevalence of the disease.

Objectives: We hypothesized that pulmonary artery pressure (PAP) significantly increases and cardiac function deteriorates during exposure to hypobaric hypoxia as encountered by traveling to moderate altitude or air flight.

Methods: A total of 37 patients (17 female; median age [quartiles] 66 years [60; 69] with COPD GOLD grade 2-3 [FEV1 57% predicted (49; 71)]) living < 800 m underwent echocardiography in Zurich (490 m) and after 1 night at Davos Jakobshorn (2,590 m) in a randomized order of allocation. Read More

Front Physiol 2018 22;9:752. Epub 2018 Jun 22.

Department of Respiratory Medicine, University Hospital Zurich, Zurich, Switzerland.

To evaluate the effects of acute exposure to high altitude and preventive dexamethasone treatment on postural control in patients with chronic obstructive pulmonary disease (COPD). In this randomized, double-blind parallel-group trial, 104 lowlanders with COPD GOLD 1-2 age 20-75 years, living near Bishkek (760 m), were randomized to receive either dexamethasone (2 × 4 mg/day p.o. Read More

Chest 2018 10 10;154(4):788-797. Epub 2018 Jul 10.

Department of Respiratory Medicine, University Hospital Zurich, Zurich, Switzerland; Kyrgyz-Swiss High Altitude Clinic and Medical Research Center, Tuja-Ashu, Kyrgyz Republic; Department of Respiratory Medicine, National Center for Cardiology and Internal Medicine, Bishkek, Kyrgyz Republic. Electronic address:

Background: Patients with COPD may experience acute mountain sickness (AMS) and other altitude-related adverse health effects (ARAHE) when traveling to high altitudes. This study evaluated whether dexamethasone, a drug used for the prevention of AMS in healthy individuals, would prevent AMS/ARAHE in patients with COPD.

Methods: This placebo-controlled, double-blind, parallel-design trial included patients with COPD and Global Initiative for Obstructive Lung Disease grade 1 to 2 who were living below 800 m. Read More

Physiol Behav 2018 05 16;188:262-269. Epub 2018 Feb 16.

Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia, Okanagan, Kelowna, Canada.

With exposure to acute normobaric hypoxia, global cerebral oxygen delivery is maintained via increases in cerebral blood flow (CBF); therefore, regional and localized changes in oxygen tension may explain neurocognitive impairment. Neurovascular coupling (NVC) is the close temporal and regional relationship of CBF to changes in neural activity and may aid in explaining the localized CBF response with cognitive activation. High-altitude related cognitive impairment is likely affected by hypocapnic cerebral vasoconstriction that may influence regional CBF regulation independent of hypoxia. Read More

Int J Appl Basic Med Res 2017 Oct-Dec;7(4):272-274

Department of Physical Medicine and Rehabilitation, AIIMS, Bhubaneswar, Odisha, India.

Sickle cell trait is a highly prevalent condition. It is not a disease. However, it has been associated with few rare complications. Read More

Arch Bronconeumol (Engl Ed) 2018 Mar 15;54(3):115-116. Epub 2017 Jul 15.

Instituto de Investigaciones de la Altura, Universidad Peruana Cayetano Heredia, Lima, Perú.

Front Physiol 2017 30;8:366. Epub 2017 May 30.

Department of Automation, Biocybernetics and Robotics, Jozef Stefan InstituteLjubljana, Slovenia.

Obesity is associated with numerous chronic ailments and represents one of the major health and economic issues in the modernized societies. Accordingly, there is an obvious need for novel treatment approaches. Recently, based on the reports of reduced appetite and subsequent weight loss following high-altitude sojourns, exposure to hypoxia has been proposed as a viable weight-reduction strategy. Read More

High Alt Med Biol 2017 Jun 22;18(2):163-170. Epub 2017 May 22.

6 Department of Surgical Sciences, Uppsala University , Uppsala, Sweden .

Counter, S. Allen, Leo H. Buchanan, Fernando Ortega, Anthony B. Read More

High Alt Med Biol 2017 Jun 16;18(2):121-127. Epub 2017 May 16.

1 Division of Wilderness Medicine, Department of Emergency Medicine, Massachusetts General Hospital , Harvard Medical School, Boston, Massachusetts.

Phillips, Lara, Buddha Basnyat, Yuchiao Chang, Erik R. Swenson, and N. Stuart Harris. Read More

Mediators Inflamm 2016 9;2016:1942460. Epub 2016 Jun 9.

Medical Intensive Care Unit, University Hospital of Zurich, 8091 Zurich, Switzerland.

Introduction. Acute exposure to high altitude induces inflammation. However, the relationship between inflammation and high altitude related illness such as high altitude pulmonary edema (HAPE) and acute mountain sickness (AMS) is poorly understood. Read More

Heart 2016 08 23;102(16):1296-301. Epub 2016 May 23.

Department of Cardiology, Center for Congenital Heart Disease, Inselspital, University Hospital, University of Bern, Bern, Switzerland.

Objective: High altitude-related hypoxia induces pulmonary vasoconstriction. In Fontan patients without a contractile subpulmonary ventricle, an increase in pulmonary artery pressure is expected to decrease circulatory output and reduce exercise capacity. This study investigates the direct effects of short-term high altitude exposure on pulmonary blood flow (PBF) and exercise capacity in Fontan patients. Read More

Wilderness Environ Med 2015 Dec;26(4 Suppl):S76-91

Longs Peak Sports Medicine, Longmont, Colorado (Dr Madden).

Children, older adults, disabled and special needs athletes, and female athletes who participate in outdoor and wilderness sports and activities each face unique risks. For children and adolescents traveling to high altitude, the preparticipation physical evaluation should focus on risk assessment, prevention strategies, early recognition of altitude-related symptoms, management plans, and appropriate follow-up. As the risk and prevalence of chronic disease increases with age, both older patients and providers need to be aware of disease and medication-specific risks relative to wilderness sport and activity participation. Read More

Trop Med Int Health 2016 Jan 12;21(1):41-51. Epub 2015 Nov 12.

Central American Population Center, University of Costa Rica, San José, Costa Rica.

Objectives: Recent studies in Central America indicate that mortality attributable to chronic kidney disease (CKD) is rising rapidly. We sought to determine the prevalence and regional variation of CKD and the relationship of biologic and socio-economic factors to CKD risk in the older-adult population of Costa Rica.

Methods: We used data from the Costa Rican Longevity and Health Aging Study (CRELES). Read More

Clin J Sport Med 2015 Sep;25(5):443-55

*Clinical Outcomes Research, Intermountain Healthcare, Salt Lake City, Utah; †Department of Family Medicine, University of Colorado, Denver, Colorado; ‡CJW Sports Medicine, Richmond, Virginia; §Anne Arundel Medical Center, Orthopedic and Sports Medicine Center, Annapolis, Maryland; ¶Missouri State University, Springfield, Missouri; ‖Department of Emergency Medicine, University of Colorado, Aurora, Colorado; **Big Island Family Medicine Center, Lynchburg, Virginia; and ††Longs Peak Sports Medicine, Longmont, Colorado.

Children, older adults, disabled and special needs athletes, and female athletes who participate in outdoor and wilderness sports and activities each face unique risks. For children and adolescents traveling to high altitude, the preparticipation physical evaluation should focus on risk assessment, prevention strategies, early recognition of altitude-related symptoms, management plans, and appropriate follow-up. As the risk and prevalence of chronic disease increases with age, both older patients and providers need to be aware of disease and medication-specific risks relative to wilderness sport and activity participation. Read More

J Appl Physiol (1985) 2015 Dec 30;119(12):1466-80. Epub 2015 Jul 30.

Sleep Disorders Center, Pulmonary Division, University Hospital of Zurich, Zurich; Switzerland; Zurich Center for Human Integrative Physiology, University of Zurich, Zurich, Switzerland; and.

Lowlanders commonly report a poor sleep quality during the first few nights after arriving at high altitude. Polysomnographic studies reveal that reductions in slow wave sleep are the most consistent altitude-induced changes in sleep structure identified by visual scoring. Quantitative spectral analyses of the sleep electroencephalogram have confirmed an altitude-related reduction in the low-frequency power (0. Read More

Exp Physiol 2015 Aug 5;100(8):905-14. Epub 2015 Jul 5.

Pulmonary Division and Sleep Disorders Center, University Hospital of Zurich, Zurich, Switzerland.

New Findings: What is the central question of this study? Cerebral hypoxia impairs cognitive function and exercise performance and may result in brain damage. Residents at high altitude, in particular those with high-altitude pulmonary hypertension, are prone to hypoxaemia due to the exposure to reduced barometric pressure and impaired pulmonary gas exchange. Whether highlanders have a reduced cerebral oxygenation has not been studied. Read More

Sleep Breath 2016 Mar 19;20(1):5-13. Epub 2015 Apr 19.

Kafkas University School of Medicine, Kars, Turkey.

Purpose: Repetitive obstruction of larynx during sleep can lead to daytime pulmonary hypertension and alterations in right ventricular morphology and function in a small fraction of obstructive sleep apnea syndrome (OSAS) patients. Environmental effects, particularly high altitude, can modify the effects of OSAS on pulmonary circulation, since altitude-related hypoxia is related with pulmonary vasoconstriction. This potential interaction, however, was not investigated in previous studies. Read More