Skeletal muscle microvascular adaptations following regular cold water immersion

This study investigated the effect of endurance training and regular post-exercise cold water immersion on changes in microvascular function. Nine males performed 3 sessions∙wk-1 of endurance training for 4 weeks. Following each session, participants immersed one leg in a cold water bath (10°C; COLD) for 15 min while the contra-lateral leg served as control (CON). Before and after training, microvascular function of the gastrocnemius was assessed using near-infrared spectroscopy, where 5 min of popliteal artery occlusion was applied and monitored for 3 min upon cuff release. Changes in Hbdiff (oxyhemoglobin - deoxyhemoglobin) amplitude (O-AMP), area under curve (O-AUC) and estimated muscle oxygen consumption (mVO₂) were determined during occlusion, while the reperfusion rate (R-RATE), reperfusion amplitude (R-AMP) and hyperemic response (HYP) were determined following cuff release. Training increased O-AMP (p=0.010), O-AUC (p=0.011), mVO₂ (p=0.013), R-AMP (p=0.004) and HYP (p=0.057). Significant time (p=0.024) and condition (p=0.026) effects were observed for R-RATE, where the increase in COLD was greater compared with CON (p=0.026). In conclusion, R-RATE following training was significantly higher in COLD compared with CON, providing some evidence for enhanced microvascular adaptations following regular cold water immersion.