Effects of Warm and Cold Contrast Footbaths on Psychological and Physiological Responses in Healthy Adults

This study aimed to measure whether 3-minute warm/cold-contrast footbaths have psychological and physiological relaxation effects, focusing on the effects of the order of the warm and cold footbaths.

Thirty healthy young adults (age: 19 ± 2 years; 23 female) participated in the study. Participants performed 2 conditions on separate days: a warm-cold footbath condition (WC condition) starting with a warm footbath (42°C warm water) and ending with a cold footbath (15°C to 20°C) and a cold-warm footbath condition (CW condition) starting with a cold footbath and ending with a warm footbath. The warm footbath was performed for 45 seconds and the cold footbath for 15 seconds per set, for a total of 3 sets of 3 minutes in length. Psychological responses were evaluated before and after the footbath using a questionnaire, and physiological responses were evaluated during the footbath by measuring heart rate, heart rate variability, and pupil diameter.

Psychological relaxation and leg lightness significantly increased after the footbath under both conditions (P = .04, P < .001). Leg warmth increased significantly after the footbath only in the CW condition (P = .001). Heart rate and pupil diameter decreased significantly from the beginning to the end of the footbath under both conditions (P = .001, P < .001); no change in heart rate variability was observed.

Three-minute warm/cold-contrast footbaths had psychological and physiological relaxation effects, regardless of the order of the warm and cold footbaths. The psychological relaxation effect may be greater if the warm footbath is at the end.