Measurement of muscle hemodynamics during bicycle exercise using diffusion correlation spectroscopy

Abstract

We adopted diffuse correlation spectroscopy (DCS) to measure blood flow velocity of vastus lateralis during cycling exercise. Participants performed a cycling exercise whose load was increased by 40 W every 2 min from 40 W to 160 W (active condition). They also performed passive pedaling exercise to verify motion artifact (passive condition). A 10 s interval was inserted following each exercise period. The average values of blood flow velocity during exercise and interval periods were compared among different exercise loads. The blood flow velocity during the exercise period was larger during active condition than passive condition. The blood flow velocity during the interval period increased with the preceding exercise load in active condition but not in passive condition, suggesting the load-dependent increase in the blood flow with active cycling exercise. Our results suggest a potential of DCS to measure active muscle blood flow during cycling exercise.