Short duration – low intensity isometric plantar flexion increases distal perfusion: observations from a healthy cohort

Abstract

Controlled physical activity might help as a preventive and therapeutic tool in vascular pathology. In this study we aimed to understand how lower limb exercise impacts perfusion in a healthy cohort. The study involved a convenience sample of eighteen previously selected healthy individuals of both sexes (n=9 each), mean age 32.8 ± 12.7 years. Procedures respected all principles of good clinical practice. Blood perfusion changes were simultaneously assessed in the dorsal region of both feet by laser Doppler flowmetry (LDF) and polarised spectroscopy (PSp). Measurements were taken at baseline, after stabilization (phase I), following 1 minute of bipedal isometric plantar flexion (phase II), and during recovery (phase III). Descriptive and comparative statistics were performed. Plantar flexion evoked significant perfusion changes in both feet, but in opposite directions – increasing with LDF and decreasing with PSp. These changes indicate that this approach promotes an adaptive mobilisation of blood from superficial to the deeper plexus. No significant changes in arterial blood pressure or cardiac frequency were detected. This manoeuvre, needing no specialised supervision, is capable of promoting significant perfusion changes in the lower limb, showing potential to be further explored in future studies with a prospective design in a preventive/recovery context. Keywords: plantar flexion; foot perfusion; laser Doppler flowmetry; polarised spectroscopy; PAHR - prompt adaptive hemodynamical response; physical activity; home-health