Table 1. Swimming time in test on exercise tolerance. Data are means (± SEM). Groups Control CE (4 wk) IHT (2 wk) CE+IHT during the first two weeks CE+IHT during the last two weeks Endurance (min) 10.0 (2.0) 18.6 (1.7)* 32.4 (2.1)*, †  68.2 (1.5)*, †  63.9 (1.4)*, †  Abbreviations: CE= chronic exercise, HT= intermittent hypoxic training, CE+IHT= chronic exercise in combination with sessions of intermittent hypoxic training during the first or the last two weeks. * p < 0.05 compared with control group, †  p < 0.05 between experimental groups.