Impact of cycling cadence on physiological response during a cardiopulmonary exercise test.

Introduction: The impact of cycling at different cadences on cardiopulmonary exercise test (CPET) measurements is poorly understood. We aimed to investigate whether higher cadences of pedalling led to meaningful changes in physiological endpoints.

Methods: Study participants were recruited from healthy staff members working within three NHS trusts across England. At baseline, all participants completed a CPET at 60 rpm and then subsequently completed CPETs at cadences of 70, 80 and 90 rpm, allocated in a random order. To evaluate the mean differences in CPET measurements across the cadences, we used a one-way repeated measures analysis of variance. We then performed post hoc pairwise comparisons with Tukey correction to account for multiple testing.

Results: Data collection took place between the 19 September 2023 and 9 April 2024. 25 participants had complete data at each cadence. 48% (12 of 25) were female, with a median (IQR) age of 30 years (27-41). There was no significant difference in peak V̇O₂ across the cadences. Maximum achieved work rate was significantly different across the cadences (p=<0.001). The highest wattage was achieved at 60 rpm (221.2 watts±71.4) and lowest at 90 rpm (210.4 watts, ±77.2). End exercise ventilation increased with increasing cadence (p=0.013), with a mean of 97.6 L/min (±28.3) at 60 prm and 107.0 L/min (±33.9) at 90 prm. Breathing reserve decreased with increasing cadence (p=0.009), with a mean of 45.6 L/min (±28.8) at 60 rpm and 35.1 L/min (±23.5) at 90 rpm. There were minimal differences in other CPET parameters.

Conclusion: In a healthy population, higher cycling cadences increased ventilatory demand and reduced maximum work rate. This could have implications for CPETs in the clinical setting, where physiological responses to higher cadences may be more exaggerated.