The main aim of this study was to investigate effects of sleep condition on acute mountain sickness during short acclimatization on the top of Mt. Fuji. Three healthy males participated in this study. Each subjects stayed one night at sea level, and stayed three night on the top of Fuji.
Respiratory variables, blood pressure, arterial saturation, heart rate variability, sleep conditions were measured.
 As a result, arterial saturation decreased on the first day during staying at the top of Fuji, and then recovered in accordance with the passage of time. In contrast, blood pressure variables as an indicator of sympathetic nerve activity continued to increase during staying on the top of Fuji.
It was suggested that this increase in sympathetic nerve activity may relate to impaired sleep condition.
 Due to small sample size, we could not observe significant differences in all variables, hence, we are trying to add last year’s data, and will present at the meeting to report results in 2016.