Acclimation to altitude using a portable hypobaric chamber at sea level may decrease the incidence of acute altitude sickness and improve physical and mental performance when traveling from sea level to altitude. PURPOSE: This study examined the effect of a cyclic variable altitude conditioning program involving intermittent hypoxic exposure at sea level, using a portable hypobaric chamber, on arterial oxygen saturation (SaO2) at the following altitudes: 2740, 3660, 4570, 5490, and 6,400 M. METHODS: Eight aerobically trained subjects completed a hypoxic training protocol that progressively exposed them to higher altitudes. Subjects acclimated for one hour per day, five days per week, for seven weeks. The highest altitude was 3200 M in the first week, 4420 M in the third week and progressed to 6860 M for the final three weeks of exposure. The SaO2 values were determined using a pulse oximeter equipped with an ear sensor prior to beginning the conditioning program (week 1) and after week 3, prior to week 4 and after week 7 of conditioning. RESULTS: Mean ± STD SaO2 values prior to conditioning were 98 ± 0 % at sea level. The following table presents the lowest SaO2 values recorded prior to and after conditioning at five altitudes.

SaO2 at various altitudes

Week	2740 M	3360 M	4570 M	2740 M	4570 M
1	90.4 ± 3.8 %	86.0 ± 4.1 %	80.9 ± 4.9 %	88.3 ± 4.6 %	78.9 ± 6.2 %
3	94.3 ± 1.4 %	90.3 ± 2.1 %	86.0 ± 3.2 %	93.1 ± 3.1 %	86.1 ± 3.5 %
Week	4570 M	5490 M	6400 M	4570 M	6400 M
4	87.8 ± 2.6 %	82.1 ± 3.7 %	73.9 ± 4.0 %	84.3 ± 5.6 %	72.0 ± 6.0 %
7	89.5 ± 2.3 %	85.1 ± 4.1 %	79.4 ± 5.6 %	87.5 ± 5.2 %	79.4 ± 5.3 %

An ANOVA for repeated measures revealed significant differences between SaO2 values between weeks 1 and 3, and weeks 4 and 7 (p<0.05). CONCLUSION: It was concluded that cyclic variable altitude conditioning resulted in an acclimation response such that arterial SaO2 was significantly increased at altitude.