When the body is exposed to sustained heat, whether from the natural environment or from a sauna, it adapts. Core temperature rises, heart rate increases, and the cardiovascular system responds by dilating the blood vessels near the skin's surface to dissipate heat. This vasodilation underlies many of the circulatory benefits of regular thermal practice, and in summer, the body is already primed for it. Ambient summer heat has been conditioning the cardiovascular system toward easier vasodilation for weeks, which means the circulatory benefits accumulate more readily than they would in the cold of winter. Research suggests women respond particularly well to regular sauna use: a 2025 study in Scientific Reports found measurable cardiovascular adaptation in women across repeated sessions, with the body showing progressive adjustment to heat exposure.