The march in place activity – a view from the local concentration of red blood cells (CRBC) in the human foot dorsum

Sedentary habits are in the origin of microcirculation dysfunctions however simple tasks might act as active preventers. This study aims to evaluate potential changes in microcirculation by using subsurface polarisation light spectroscopy in human foot, while march in place. Eleven healthy volunteers (25.6 ± 5.4 years) of both sexes, normal ankle-brachial index (1.08 ± 0.15) participated in this study. The protocol consists of one minute in standing position (Phase 1); one minute of march in place (Phase 2), and one minute of recovery (Phase 3). The local CRBC was assessed by the Tissue Viability Imaging® System probe, detecting changes between Phase 1 and Phase 2 (p=0.016) but not for Phase 3 (p=0.113). Photoplethysmography (PPG) was also used, revealing significant changes in Phase 3 both for wave amplitude (p=0.016) and pulse rate (p=0.005). These findings can be explained as a physiological response to movement. Gender differences were found in Phases 2 and 3 (p=0.011 and p=0.006), with higher CRBC values in men. Simultaneously the gastrocnemius was evaluated using surface electromyography (sEMG) with significant increases observed in Phase 2 (p=0.003). Nevertheless, additional studies are needed to understand the behaviour of the microcirculation during physical activity.