Foot immersion fails to lessen increases in core temperature in elderly exposed to extreme heat: JAMA

Following approval of the study by the University of Ottawa Research Ethics Board, adults aged 65 to 85 years from the Ottawa, Canada, region volunteered and provided written informed consent for the study, which ran from September 2022 to May 2023.

The primary outcome was core (rectal) temperature. A reduction of 0.2 °C or more was chosen as the minimal clinically meaningful effect. A sample of at least 15 participants was required to detect this effect with 84% power.

Results

Of 25 individuals assessed for eligibility, 17 participated

The mean core temperature increased by 1.1 °C in control, 1.1 °C in foot immersion, and 1.2 °C in foot immersion with neck cooling and reached 38.0 °C at the end of exposure in each group.

There were no statistically significant differences in core temperature between groups (all pairwise differences, 0.0 °C

Foot immersion with and without neck cooling did not lessen increases in core temperature in older adults in this small study conducted in a controlled experimental setting. Although some effects on heart rate, sweat rate, and fluid consumption were observed, they were small and of questionable clinical importance.

These data do not support foot immersion and neck cooling as efficacious strategies for limiting increases in core temperature in older adults. The homogeneous sample and specific environmental conditions limit study generalizability.

Reference:

Meade RD, McCourt ER, McCormick JJ, Boulay P, Sigal RJ, Kenny GP. Body Core Temperature After Foot Immersion and Neck Cooling in Older Adults Exposed to Extreme Heat. JAMA. Published online December 21, 2023. doi:10.1001/jama.2023.24417

Keywords:

Foot, immersion, without, neck, cooling, fail, lessen, increases, core, temperature, elderly, JAMA, Meade RD, McCourt ER, McCormick JJ, Boulay P, Sigal RJ, Kenny GP