Body mass and composition changes in mountaineers after a commercial expedition on Denali (6194 m)

Sojourns to high altitude have resulted in weight loss, but there is a lack of data from guided commercial expeditions. The purpose of this study was to determine the body mass and composition changes in mountaineers after a commercial climbing expedition on Denali (6194 m). Eleven mountaineers began the expedition, and 8 (5 clients, 3 guides; 7 males, 1 female; age: 37.4 ± 10.1 yrs) completed the study; all 8 reached the summit. Pre- and post-data, spanning 21 days, were collected in Talkeetna, AK (105 m). Body mass and body fat percentage (%BF) were obtained with a fullbody bioelectrical impedance scale. Every participant lost weight (-2.9 ± 1.4 kg, P = .001; -0.8 to -5.2 kg), and on average there was a significant drop in %BF (-3.0 ± 3.1% BF, P = .029). There was a tendency for the clients to lose more weight (-3.5 ± 1.1 kg vs. -2.0 ± 1.5 kg, P = .149) and %BF (-4.8 ± 1.4% BF vs. -0.1 ± 3.1% BF, P = .024) than the guides. Neither the pre-expedition mass nor %BF were significantly (P\u3e0.05) correlated with the losses. Despite sleeping only 3 nights above 5000 m with no food restrictions, mountaineers lost a significant amount of mass and %BF during a 3-wk commercial expedition on Denali. Additional research is needed with a larger sample to make more definitive comparisons between groups of mountaineers (commercial vs. non-commercial expeditions, clients vs. guides, and males vs. females)