Schommer K.,University of Heidelberg |
Wiesegart N.,University of Heidelberg |
Menold E.,University of Heidelberg |
Haas U.,Hohenbalance AG |
And 4 more authors.
High Altitude Medicine and Biology
Schommer, Kai, Neele Wiesegart, Elmar Menold, Ute Haas, Hermann Buhl, Pezter Bärtsch, and Christoph Dehnert. Training in normobaric hypoxia and its effects on acute mountain sickness after rapid ascent to 4559m. High Alt. Med. Biol. 11:19-25, 2010.-In a randomized, placebo-controlled, double-blind study, we tested a 4-week program in normobaric hypoxia that is commercially offered for the prevention of acute mountain sickness (AMS). Twenty-two male and 18 female healthy subjects [mean age 33±7 (SD) years] exercised 70min, 3x/week for 3 weeks on a bicycle ergometer at workloads of 60% Vo2max either in normoxia (normoxia group, NG) or in normobaric hypoxia (hypoxia group, HG), corresponding to altitudes of 2500, 3000, and 3500m during weeks 1, 2, and 3, respectively. Four passive exposures of 90min in normoxia (NG) or hypoxia corresponding to 4500m (HG) followed in week 4. Five days after the last session, subjects ascended within 24h from sea level to 4559m (one overnight stay at 3611m) and stayed there for 24h. AMS was defined as LL (Lake Louise score) ≥5 and AMS-C ≥0.70. The AMS incidence (70% in NG vs. 60% in HG, p=0.74), LL scores (7.1±4.3 vs. 5.9±3.4, p=0.34), and AMS-C scores (1.50±1.22 vs. 0.93±0.81, p=0.25) at the study endpoint were not significantly different between the groups. However, the incidence of AMS at 3611m (6% vs. 47%, p=0.01) and the functional LL score at 4559m were lower in HG. Spo2 at 3611m, heart rate during ascents, and arterial blood gases at 4559m were not different between groups. We conclude that the tested program does not reduce the incidence of AMS within a rapid ascent to 4559m, but our data show that it prevents AMS at lower altitudes. Whether such a program would prevent AMS at higher altitudes, but with slower ascent, remains to be tested. © Copyright 2010, Mary Ann Liebert, Inc. 2010. Source
Wiesner S.,Max Delbruck Center for Molecular Medicine |
Haufe S.,Max Delbruck Center for Molecular Medicine |
Engeli S.,Max Delbruck Center for Molecular Medicine |
Engeli S.,Hannover Medical School |
And 5 more authors.
Previous studies suggested that hypoxia and exercise may have a synergistic effect on cardiovascular and metabolic risk factors. We conducted a single blind study in overweight to obese subjects to test the hypothesis that training under hypoxia (HG, n = 24, FiO 2 = 15%) results in similar or even greater improvement in body weight and metabolic risk markers compared with exercise under normoxia (NG, n = 21, FiO 2 = 21%). After an initial metabolic evaluation including incremental exercise testing, subjects trained in normoxic or hypoxic conditions thrice weekly over a 4-week period at a heart rate corresponding to 65% of maximum oxygen uptake (VO 2max). The experimental groups were similar at the start of the investigation and weight stable during the training period. Subjects in the hypoxia group trained at a significantly lower workload (P 0.05). Yet, both groups showed similar improvements in VO 2max and time to exhaustion. Respiratory quotient and lactate at the anaerobic threshold as well as body composition improved more in the hypoxia group. We conclude that in obese subjects, training in hypoxia elicits a similar or even better response in terms of physical fitness, metabolic risk markers, and body composition at a lower workload. The fact that workload and, therefore, mechanic strain can be reduced in hypoxia could be particularly beneficial in obese patients with orthopedic comorbidities. Source