Acute Sauna Session and Glucose Control

At least 72 hours prior to the first trial, participants will complete a familiarization session consisting of two 20-minute infrared sauna exposures. The study employs a randomized crossover design, with each participant completing both experimental conditions-infrared sauna (two 20-minute sessions at 175°F / 79°C, separated by a 5-minute break) and seated rest (two 20-minute periods of quiet sitting, separated by a 5-minute break)-separated by at least 72 hours. On each trial day, participants will arrive at the laboratory at 7:50 a.m. after an overnight fast from 8:00 p.m., with water permitted throughout. Participants will wear a continuous glucose monitor (CGM) during both trial days. Baseline measurements of blood pressure, heart rate, and oral body temperature will be recorded, and food logs reviewed. Following the condition session, a sedentary recovery period will occur until 9:45 a.m., with repeated physiological measurements. Final measurements of blood pressure, heart rate, and oral body temperature will be collected prior to a standardized breakfast provided from 9:45 to 10:10 a.m. Participants will depart thereafter by car or public transportation and remain sedentary for the remainder of the day. Meals for the rest of the day, i.e., breakfast, lunch, dinner, and a bedtime snack, will be provided and identical across trial days. Participants will fast again from 9:00 p.m. until 9:00 a.m. the following morning.