Fractional O2 extraction and fitness among physically active and inactive children during post-exercise recovery

Abstract

This study aimed to determine the differences in muscle O2 extraction capacity and physical fitness between physically active and sedentary schoolchildren. 19 students aged 10 to 14 years participated, categorized as physically active or inactive. In addition, a battery of basic physical condition and cardiovascular variables assessments was carried out. Physically active children demonstrated significantly greater efficiency in muscle O2 extraction and resaturation during post-exercise recovery compared to sedentary counterparts (17.8 ± 8.11s vs 26.1 ± 8.54 s; p = 0.004; η2p: 0.271). In the physical fitness tests there were only significant differences in the 30s Chair Stand Test (27.8 ± 3.97 vs. 19.4 ± 2.88 reps. P=< 0.001 η2p: 0.614). These findings underscore the potential of regular physical activity to optimize peripheral vascular response and muscle oxygen utilization during post-exercise recovery in children.