Study interventions
WBH
HEAT
For both WBH and the sham condition, the current study used a Heckel HT3000 WBH system (Heckel Medizintechnik GmbH and Hydrosun Medizintechnik GmbH). Participants randomized to active WBH received heating at the level of the chest by infrared lights and at the level of the lower extremities by infrared heating coils until their core body temperature reached 38.5 °C, which is the upper limit of core body temperature for mild-intensity WBH [All procedures for the sham condition were identical to WBH, except that the primary infrared lights were not turned on, and orange-colored non-heating lights were placed at the level of the chest to produce a similar color, but no heat. To increase believability, mild heat was provided within the Heckel device by activating heating coils situated above the participants’ lower extremities at the same setting used for active WBH. Finally, a false fan was used to produce noise, as when the device was fully operational. The duration of exposure to the sham WBH condition was matched to the duration of time that the prior participant of the same sex undergoing actual WBH spent in the active heating phase.