The Effect of Daily Brief Heat Exposures on Heat Acclimation

The Effect of Daily Brief Whole-body Heat Exposures on Heat Acclimation and Its Decay

This study is the first to examine the effects of short passive heat exposure on heat acclimation (HA). Unlike traditional protocols requiring prolonged heat exposure, this study tests whether a daily 5-minute whole-body immersions at 45°C water repeated over two weeks can trigger adaptive responses, offering a potentially more accessible and time-efficient method for heat acclimation. This study aims to investigate whether brief, repeated passive heat exposure can induce HA in both female and male participants. It evaluates changes across physiological, biological, and psychological markers to determine the efficacy of this minimal-exposure protocol. It is hypothesized that such short, repeated immersions may be sufficient to elicit significant adaptive responses across key HA indicators.

Inclusion Criteria:

• Healthy, non-obese males and females aged 18 to 35 years with a body mass index between 18.5 and 29.9 kg/m².
• No participation in temperature manipulation programs (e.g., cold or heat acclimation) within the past three months.
• No engagement in excessive formal exercise.
• Female participants must have a regular menstrual cycle.

Exclusion Criteria:

• Current smokers.
• Fear of needles or blood.
• Use of medications or supplements that could affect study outcomes.
• History of neurological, cardiovascular, metabolic, or inflammatory diseases that could be aggravated by hot water exposure.