Cold water immersion recovery strategy increases blood pressure levels after high-intensity intermittent exercise

BACKGROUND: This study aimed to investigate the effects of cold water immersion (CWI) recovery strategies on the blood pressure levels and related physiological parameters after high-intensity intermittent exercise (HIIE). METHODS: This randomized crossover study included 20 men (21.5 +/- 1.6 years). Each participant performed a maximum-exertion exercise performance test on a bicycle, and heart rate was measured. Subsequently, six cycles of HIIE (1 minute at 120% heart rate reserve [HRR] and 4 minutes at 40% HRR) were performed in a random sequence, and the recovery period involved either CWI or static rest (SR). RESULTS: Systolic and diastolic blood pressure levels at the 6th and 20th minute of CWI recovery were significantly higher than those during SR and significantly higher than those during a quiet state at the 6th minute. The heart rates at the 20th minute and 35th minute of CWI recovery were significantly lower than that during SR, and the ratings of perceived exertion (RPE) at the 6th and 20th minute of CWI recovery were significantly lower than that during SR. No significant difference in lactate production was evident between the two recovery strategies. Ear temperature was not significantly different when it was quiet, at the end of exercise, and at the 6th and 35th minute of recovery; however, at the 20th minute of recovery, ear temperature during CWI was significantly higher than that during SR. CONCLUSIONS: CWI after HIIE reduced the extent to which blood pressure decreased. For the fatigue-related heart rate and RPE indicators, CWI was superior to SR.