Subalpine training at 1,200 m altitude for 8 weeks: impact on aerobic and anaerobic capacity, cardiac function, and hemodynamics in male paralympic biathletes.

Subalpine training plays an important role in the physical conditioning and performance enhancement of athletes. Previous studies have analyzed the characteristics of changes in cardiac and electroencephalographic indices, but there is a gap in current research to investigate the changes in energy metabolism, cardiac function, and hemodynamics in biathletes with disabilities who underwent 8 weeks of subalpine training at 1,200 m altitude. It is important to explore the changes of these indicators to guide the scientific training and competition of disabled biathletes. To investigate the effects of 8 weeks of subalpine training at 1,200 m altitude on aerobic and anaerobic capacity, cardiac function, and hemodynamics of male Paralympic biathletes, and to make scientific recommendations for the training and participation of para-biathletes. Energy metabolism, cardiac function, and hemodynamics are crucial physiological indicators reflecting athletes' physical stress, exercise capacity, and circulatory regulation. Therefore, these indicators were measured to reveal the physiological adaptation of athletes during high-intensity exercise. 14 male biathletes [age (23.9 ± 2.4), height (176.3 ± 7.6) cm, and body mass (58.2 ± 8.9) kg] from the national winter Paralympic training team were trained for 8 weeks at a subalpine altitude of 1,200 m. Their aerobic and anaerobic capacity, cardiac function, and hemodynamic parameters were assessed before, during, and after the subalpine training, and their data were compared using repeated measures analysis. After two weeks of subalpine training, athletes had significantly elevated cardiac index (p < 0.001), variability in output per beat (p < 0.001), and thoracic fluid content (p < 0.001), and significantly decreased output per beat (p < 0.001) and left ventricular ejection time (p < 0.001). Additionally, we found that after 8 weeks of subalpine training, their cardiac index was significantly higher than before subalpine training (p < 0.001). There was no significant change in beat-to-beat output (p = 0.904), beat-to-beat output variability (p = 0.866) or thoracic fluid content from (p = 0.208) before subalpine, and the left ventricular ejection time was significantly lower than before subalpine (p = 0.003). After eight weeks of subalpine training at 1,200 m, the male Paralympic biathletes demonstrated a significant decrease in aerobic capacity indices, including peak oxygen uptake (VO2peak) and ventilation (p<0.05), while no significant change was observed in anaerobic capacity indices such as peak power, mean power and fatigue index (p>0.05). The study findings suggest that subalpine training for two weeks can lead to reduced circulatory system volume and inflammatory pleural effusion in Paralympic biathletes. However, 8 weeks of subalpine training at 1,200 m altitude can enhance stress resistance, adaptability, cardiac function, and cardiac reserve while significantly reducing aerobic capacity in Paralympic biathletes. When conducting subalpine training, the physical function monitoring of Paralympic biathletes might be available to focus on cardiovascular function and thermodynamics-related microcirculatory indicators. Additionally, a comprehensive assessment of the circulatory and respiratory systems' functional status could be performed to maintain and improve training quality and competitive status.