Effects of footbath depth on dorsal foot skin temperature and psychological measures

Abstract

This study aimed to compare dorsal foot skin temperature and perceptions of water temperature, comfort, and anxiety during footbaths based on water depth, using a crossover design.

Participants submerged their feet in a foot-soaking tub for 10 min while seated. Footbaths were maintained at 40°C and filled to a height of either 8 cm or 15 cm. Dorsal foot skin temperature (“skin temperature”), perceived warmth and comfort, and the State-Trait Anxiety Inventory (STAI) were assessed before, during, immediately after, and 10 min after immersion.

There were 22 participants (M/F: 5/17, age: 21±3 y/o). In both depth conditions, participants reported that their bodies were warm and comfortable during and immediately after immersion, and skin temperature remained high even 10 min afterwards, suggesting reduced anxiety. Relaxation from the pleasant warmth may have been caused by the footbaths inducing a shift to parasympathetic dominance.

Compared with the 8-cm condition, participants felt their bodies were significantly warmer during immersion than baseline in the 15-cm condition and, despite showing significantly greater reductions in perceived warmth from directly after to 10 min after immersion, endorsed persistent feelings of comfort even 10 min after their feet were averted. Such findings suggest that filling footbaths to a height of 15 cm, thereby exposing more surface area to contact with warm water, more effectively induces pleasant feelings during and after immersion.