Table 1 PICO — Population, Interventions, Comparisons, Outcomes

Population

Healthy male or female adults ≥ 18 years of age of any race or ethnicity, in any research setting

Interventions

Daily exercise^a under thermoneutral environmental conditions (< 25 °C) followed by post-exercise heat exposure^b for at least 2 consecutive days, with baseline and post-intervention exercise performance tests completed in either thermoneutral or hot (≥ 25 °C) conditions.^c

Comparisons

The control group must complete the same daily exercise intervention but without post-exercise heat exposure.^d

Outcomes

Primary outcome:

Endurance exercise performance measured by time-to-completion (time trial or race) or time-to-exhaustion tests in hot conditions

Secondary outcomes:

(i) Endurance exercise performance measured by time-to-completion (time trial or race) or time-to-exhaustion tests in thermoneutral conditions

(ii) V̇O₂max, economy/efficiency, and/or lactate threshold in hot or thermoneutral conditions

(iii) RPE, heart rate, core temperature, sweat rate, thermal sensation, and thermal comfort during exercise in hot or thermoneutral conditions

(iv) All outcome variables in trained athletes vs. non-athletes