PHYSIOLOGICAL IMPACTS OF HYDRO ENVIRONMENT EXTRAVEHICULAR ACTIVITY TRAINING IN COSMONAUTS

Abstract

Aim. This paper aims to investigate the effects of standard extravehicular activity (EVA) training in a hydro environment on physical performance and muscle strength in cosmonauts. Materials and methods. Sixteen cosmonauts (mean age – 39.5 ± 6.5 years, mean height – 176.7 ± 4.8 cm, mean weight – 82.9 ± 9.2 kg) underwent 4 h 50 min ± 25 min of training in the Orlan-GN spacesuit (Hydrolab, Gagarin Cosmonaut Training Center) at an internal pressure of 0.4 kg/cm². Physiological measurements (heart rate, body temperature) and energy consumption were recorded during the EVA training. Anthropometric measurements (body weight), muscle strength (handgrip and back muscles), and physical performance were evaluated pre- and post-training. Results. The results obtained demonstrated the following: a decrease in body weight throughout the training period; physiological responses to standard EVA operations within the age-related physiological norm throughout the training period; decreased physical performance and significant muscle fatigue post-training. Conclusion. The key findings indicate dehydration, reduced cardiovascular reactivity at rest, decreased exercise tolerance, and increased muscle fatigue. These results have critical implications for space mission planning and EVA operations on the international space station.