Nutritional Strategies for the Preservation of Fat Free Mass  at High Altitude

Wing‐Gaia, Stacie L.

doi:10.3390/nu6020665

Cited by 28 publications

(25 citation statements)

References 78 publications

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“…The average water content of FFM is about 73% and therefore it is not surprising that TBW accounted for the majority of FFM losses [39]; however, the higher loss of ICW compared to ECW indicates a highly catabolic state and mobilization of metabolically active body cell mass [40]. These changes in body composition have been a common observation in studies conducted at high altitude and it could represent an adaptive protective mechanism under conditions of reduced oxygen availability [9]. Murray & Montgomery have advanced the hypothesis that free amino acids and ketone bodies may act as both substrates and metabolic modulators to protect cells from the hypoxic challenge by improving mitochondrial efficiency, activating ATP-sensitive potassium channel and reducing the production of reactive oxygen species [41].…”

Section: Discussionmentioning

confidence: 99%

Does hypoxia play a role in the development of sarcopenia in humans? Mechanistic insights from the Caudwell Xtreme Everest Expedition

et al. 2017

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ObjectivesSarcopenia refers to the involuntary loss of skeletal muscle and is a predictor of physical disability/mortality. Its pathogenesis is poorly understood, although roles for altered hypoxic signaling, oxidative stress, adipokines and inflammatory mediators have been suggested. Sarcopenia also occurs upon exposure to the hypoxia of high altitude. Using data from the Caudwell Xtreme Everest expedition we therefore sought to analyze the extent of hypoxia-induced body composition changes and identify putative pathways associated with fat-free mass (FFM) and fat mass (FM) loss.MethodsAfter baseline testing in London (75 m), 24 investigators ascended from Kathmandu (1300 m) to Everest base camp (EBC 5300 m) over 13 days. Fourteen investigators climbed above EBC, eight of whom reached the summit (8848 m). Assessments were conducted at baseline, during ascent and after one, six and eight week(s) of arrival at EBC. Changes in body composition (FM, FFM, total body water, intra- and extra-cellular water) were measured by bioelectrical impedance. Biomarkers of nitric oxide and oxidative stress were measured together with adipokines, inflammatory, metabolic and vascular markers.ResultsParticipants lost a substantial, but variable, amount of body weight (7.3±4.9 kg by expedition end; p<0.001). A progressive loss of both FM and FFM was observed, and after eight weeks, the proportion of FFM loss was 48% greater than FM loss (p<0.008). Changes in protein carbonyls (p<0.001) were associated with a decline in FM whereas 4-hydroxynonenal (p<0.001) and IL-6 (p<0.001) correlated with FFM loss. GLP-1 (r=−0.45, p<0.001) and nitrite (r=−0.29, p<0.001) concentration changes were associated with FFM loss. In a multivariate model, GLP-1, insulin and nitrite were significant predictors of FFM loss while protein carbonyls were predicted FM loss.ConclusionsThe putative role of GLP-1 and nitrite as mediators of the effects of hypoxia on FFM is an intriguing finding. If confirmed, nutritional and pharmacological interventions targeting these pathways may offer new avenues for prevention and treatment of sarcopenia.

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Section: Discussionmentioning

confidence: 99%

Does hypoxia play a role in the development of sarcopenia in humans? Mechanistic insights from the Caudwell Xtreme Everest Expedition

et al. 2017

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“…First, there is an association between chronic high altitude exposure and significant weight loss. 69 This seems to be primarily due to loss of fat-free mass, which may have significant negative effects on physical performance. 69 Factors possibly contributing to this weight loss are decreased physical activity, hypoxia, irregular sleep pattern, cold exposure, and nutritional imbalance related to protein metabolism.…”

Section: Physiologic Response To Altitude and Medical Considerationsmentioning

confidence: 99%

“… 69 This seems to be primarily due to loss of fat-free mass, which may have significant negative effects on physical performance. 69 Factors possibly contributing to this weight loss are decreased physical activity, hypoxia, irregular sleep pattern, cold exposure, and nutritional imbalance related to protein metabolism. 1 , 19 , 34 , 50 , 69 Based on a few small studies, it seems that increasing caloric intake is not the best way to retain fat-free mass at altitude.…”

Section: Physiologic Response To Altitude and Medical Considerationsmentioning

confidence: 99%

“… 69 Factors possibly contributing to this weight loss are decreased physical activity, hypoxia, irregular sleep pattern, cold exposure, and nutritional imbalance related to protein metabolism. 1 , 19 , 34 , 50 , 69 Based on a few small studies, it seems that increasing caloric intake is not the best way to retain fat-free mass at altitude. 69 Increasing protein intake, particularly leucine, may be a more practical strategy.…”

Section: Physiologic Response To Altitude and Medical Considerationsmentioning

confidence: 99%

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Athletes at High Altitude

Khodaee

Grothe

Seyfert

et al. 2016

Sports Health: A Multidisciplinary Approach

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Context:Athletes at different skill levels perform strenuous physical activity at high altitude for a variety of reasons. Multiple team and endurance events are held at high altitude and may place athletes at increased risk for developing acute high altitude illness (AHAI). Training at high altitude has been a routine part of preparation for some of the high level athletes for a long time. There is a general belief that altitude training improves athletic performance for competitive and recreational athletes.Evidence Acquisition:A review of relevant publications between 1980 and 2015 was completed using PubMed and Google Scholar.Study Design:Clinical review.Level of Evidence:Level 3.Results:AHAI is a relatively uncommon and potentially serious condition among travelers to altitudes above 2500 m. The broad term AHAI includes several syndromes such as acute mountain sickness (AMS), high altitude pulmonary edema (HAPE), and high altitude cerebral edema (HACE). Athletes may be at higher risk for developing AHAI due to faster ascent and more vigorous exertion compared with nonathletes. Evidence regarding the effects of altitude training on athletic performance is weak. The natural live high, train low altitude training strategy may provide the best protocol for enhancing endurance performance in elite and subelite athletes. High altitude sports are generally safe for recreational athletes, but they should be aware of their individual risks.Conclusion:Individualized and appropriate acclimatization is an essential component of injury and illness prevention.

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“…However, body hydration status was not measured in any of the studies. In addition, body weight loss is a normal altitude acclimatization response due to increased energy expenditure, increased water loss, and decreased energy intake at altitude and could not be prevented (Wing‐Gaia ). All volunteers participated in physical activity including exercise tests upon arrival at 4 km or graded hiking bouts while staging or ascending to 4 km.…”

Section: Methodsmentioning

confidence: 99%

New metric of hypoxic dose predicts altitude acclimatization status following various ascent profiles

et al. 2019

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Medical personnel need practical guidelines on how to construct high altitude ascents to induce altitude acclimatization and avoid acute mountain sickness (AMS) following the first night of sleep at high altitude. Using multiple logistic regression and a comprehensive database, we developed a quantitative prediction model using ascent profile as the independent variable and altitude acclimatization status as the dependent variable from 188 volunteers (147 men, 41 women) who underwent various ascent profiles to 4 km. The accumulated altitude exposure (AAE), a new metric of hypoxic dose, was defined as the ascent profile and was calculated by multiplying the altitude elevation (km) by the number of days (d) at that altitude prior to ascent to 4 km. Altitude acclimatization status was defined as the likely presence or absence of AMS after ~24 h of exposure at 4 km. AMS was assessed using the Cerebral Factor Score (AMS‐C) from the Environmental Symptoms Questionnaire and deemed present if AMS‐C was ≥0.7. Other predictor variables included in the model were age and body mass index (BMI). Sex, race, and smoking status were considered in model development but eliminated due to inadequate numbers in each of the ascent profiles. The AAE (km·d) significantly (P < 0.0001) predicted AMS in the model. For every 1 km·d increase in AAE, the odds of getting sick decreased by 41.3%. Equivalently, for every 1 km·d decrease in AAE, the odds of getting sick increased by 70.4%. Age and BMI were not significant predictors. The model demonstrated excellent discrimination (AUC = 0.83 (95% CI = 0.79–0.91) and calibration (Hosmer‐Lemeshow = 0.11). The model provides a priori estimates of altitude acclimatization status resulting from the use of various rapid, staged, and graded ascent profiles.

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Nutritional Strategies for the Preservation of Fat Free Mass at High Altitude

Cited by 28 publications

References 78 publications

Does hypoxia play a role in the development of sarcopenia in humans? Mechanistic insights from the Caudwell Xtreme Everest Expedition

Does hypoxia play a role in the development of sarcopenia in humans? Mechanistic insights from the Caudwell Xtreme Everest Expedition

Athletes at High Altitude

New metric of hypoxic dose predicts altitude acclimatization status following various ascent profiles

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