Fig. 1

Overview of the study design. Participants were exposed to passive heat stress with a water-perfused suit before and after heat acclimation. During the pre-acclimation visit, participants were heated until core temperature increased ~1.4 °C. During the post-acclimation visit, participants were heated until core temperature attained the same absolute value that was reached during the pre-acclimation visit (~38.2 °C). Blood samples were drawn before and at the end of heat stress for plasma proteomic analyses. The heat acclimation protocol involved hot water immersion at shoulder level until core temperature reached 38.6 °C, after which participants sat within the water bath to maintain core temperature ≥38.6 °C for 60 minutes.