Key result
Semi-upright cycling increases cardiac output ~23% more than upright cycling alongside higher perceived exertion.
Why the study?
The effect of hemodynamic conditions induced by a semi-upright body position on the integrative physiological response to exercise is poorly understood.
Does a semi-upright body position alter cardiovascular, skeletal muscle, and ventilatory responses during submaximal cycling compared to an upright position in healthy individuals?
Does a semi-upright body position alter cardiovascular, skeletal muscle, and ventilatory responses during submaximal cycling compared to an upright position in healthy individuals?
Absolute Event Rate: 7.9% vs 6.4%
p-value: p=<0.001
Semi-upright cycling produces greater elevations in cardiac output and perceived exertion but blunted oxygen consumption compared to upright cycling, suggesting altered skeletal muscle perfusion.
May necessitate position-specific norms in exercise testing; leaves open effects in clinical populations.
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.
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Bentley et al. (2024) studied Healthy (n=20). Semi-upright (40° incline) cycling vs. Upright cycling was evaluated on Increase in cardiac output (CO) (p=<0.001). Semi-upright cycling resulted in a greater increase in cardiac output compared to upright cycling (7.9 vs. 6.4 L/min, P<0.001), alongside higher perceived exertion and attenuated oxygen consumption.
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