Background:
Hypobaric hypoxia causes complex structural and functional changes that can manifest themselves in different ways depending on the individual level of adaptability. Studying these reactions allows for the optimization of training loads of highly skilled athletes.

Material and methods:
The study examined 15 highly skilled race walkers during a 14-day training camp in medium mountain conditions (1,600 m above sea level). Heart rate, systolic and diastolic blood pressure were measured daily in a state of functional rest.

Results:
Unstable heart rate indicators were observed during the first 4-5 days of remaining in medium mountain conditions. Some athletes showed a decrease and stabilization of heart rate starting from the 5th-6th day, which indicated effective acclimatization. Blood pressure indicators remained relatively stable in most participants.

Conclusions:
A relatively high reactivity of heart rate values at the beginning of acclimatization was revealed. The 4-5-day period was defined as the period of mobilization of adaptation processes, which requires a decrease in training loads during this period. In general, we consider it advisable for athletes to stay longer (more than 14 days) in mid-mountain conditions. At the same time, highly adaptive individuals can begin more intensive training after 5-6 days of stay.