Changes in performance, maximal oxygen uptake and maximal accumulated oxygen deficit after 5, 10 and 15 days of live high: Train low altitude exposure

Nineteen well-trained cyclists (14 males and 5 females, mean initial VO_2max 62.3 ml kg^-1 min^-1) completed a multistage cycle ergometer test to determine maximal mean power output in 4 min (MMPO_4min), maximal oxygen uptake (VO_2max) and maximal accumulated oxygen deficit (MAOD). The athletes were divided into three groups, each of which completed 5, 10 or 15 days of both a control condition (C) and live high:train low altitude exposure (LHTL). The C groups lived and trained at the ambient altitude of 610 m. The LHTL groups spent 8-10 h night^-1 in normobaric hypoxia at a simulated altitude of 2,650 m, and trained at the ambient altitude of 610 m. The changes to MMPO_4min, VO_2max and MAOD in response to LHTL altitude exposure were not significantly different for the 5-, 10- and 15-day treatment periods. For the pooled data from all three treatment periods, there were significant increases in MMPO_4min [mean (SD) 5.15 (0.83) W kg^-1 vs 5.34 (0.78) W kg^-1] and MAOD [50.1 (14.2 ml kg^-1 vs 54.9 (13.1) ml kg^-1] in the LHTL athletes between pre- and post-altitude exposure. There were no significant changes in MMPO_4min [5.09 (0.76) W kg^-1 vs 5.16 (0.86) W kg^-1] or MAOD [50.5 (14.1) ml kg^-1 vs 49.1 (13.0) ml kg^-1] in the C athletes over the corresponding period. There were significant increases in VO_2max in the athletes during both the LHTL [63.2 (9.0) ml kg^-1 min^-1 vs 64.1 (9.0) ml kg^-1 min^-1] and C [62.0 (8.6) ml kg^-1 min^-1 vs 63.4 (9.2) ml kg^-1 min^-1] conditions. In these athletes, there was no difference in the impact of 5, 10 or 15 days of LHTL on the increases observed in MMPO_4min, VO_2max or MAOD; and LHTL increased MMPO_4min and MAOD more than training at low altitude alone.