2024/12/17 by Robert F. Bentley, Jonaline B. Bernal, Daniel C. Basile +2 · 1 voice
Medicine · #Cardiovascular and exercise physiology #Heart Rate Variability and Autonomic Control #Sports Performance and Training
paper · pdf · doi:10.1113/ep092256
openalex publication_date 2024/12/17 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/01
Abstract The completion of exercise in different body positions can impact the function of various components of the oxygen delivery pathway; however, the effect of the haemodynamic conditions induced by a semi‐upright body position on the integrative physiological response to exercise is poorly understood. The purpose of this study was to explore the effect of a semi‐upright body position on cardiac output (CO), vastus lateralis oxygen saturation (), oxygen consumption () and ratings of perceived exertion (Borg RPE) during submaximal cycling. Twenty healthy individuals (22 ± 3 years, 50% female) each completed alternating 5‐min bouts of submaximal upright and semi‐upright (40° incline) cycling at 50 and 100 W. CO, , and RPE were assessed at rest and at each exercise intensity during steady state. There was a main effect of intensity on the increase in CO, , and RPE (all P < 0.001). In a semi‐upright position, the increase in CO (7.9 ± 2.8 vs. 6.4 ± 2.6 L/min, P < 0.001), RPE (median (interquartile range): 11 (9–13) vs. 10 (8–12), P = 0.013) and the decrease in (−38 ± 23 vs. −21% ± 18%, P < 0.001) were greater than upright, while the increase in was attenuated (1.030 ± 0.130 vs. 1.154 ± 0.165 L/min, P < 0.001). These results suggest that while a semi‐upright body position produces elevations in CO, these elevations do not seem to perfuse the active skeletal muscle. This may explain the elevation in RPE despite a blunting in the increase in . Further work is required to understand the effects of a semi‐upright exercise position on skeletal muscle activation and lower limb blood flow.