Acute effects of cold water immersion on cardiovascular and autonomic responses

Abstract

Background: Immersion has been used for many years for therapeutic purposes, but more recently the cardiovascular and authonomic effects appear as an important change in the organism during immersion in the aquatic environment.

Objectives: The aim of this study was to investigate the acute effect of water immersion (22.6 °C) on heart rate, heart rate variability, body temperature, oxygen saturation, diastolic blood pressure and systolic blood pressure in young apparently healthy men.

Method: Nine apparently healthy males were randomly allocated to an experimental situation (SE) and one control (SC). The SE subjects had the variables measured after the 10 minutes immersion. The subject of the SC remained 10 minutes at rest in the terrestrial environment. After 48h, the procedures were performed the reverse manner to perform balanced input.

Results: After 10 minutes of immersion in water was observed reduction in the values of heart rate, significant increases on the RR intervals. The values of RMSSD (ms) increased after immersion, as shown pNN50 (%) and HF index increased (p = 0.009). The ratio (LF / HF) decreased after immersion. Significant differences when comparing the SBP were observed.

Conclusions: Thus, is concluded that the immersion in water (22.6º C) increases vagal activity and reduces modulation of the sympathetic branch of the autonomic nervous system.