A recent scientific review examining heat exposure (such as sauna bathing) and cold-water immersion found that both therapies act as mild, controlled stressors that can trigger beneficial adaptations in the body. When exposed to heat—like in a sauna—the heart rate increases and blood vessels widen, improving circulation and placing a gentle, exercise-like demand on the cardiovascular system. Cold exposure, such as a cold plunge, causes the opposite response: blood vessels constrict, the nervous system becomes more alert, and the body activates processes that help regulate temperature and reduce inflammation. Over time, these temperature stresses may help support cardiovascular health, metabolic function, and the body’s ability to adapt to physical stress.
The research also highlights the potential benefits of contrast therapy, which alternates between heat and cold exposure. Moving from a sauna into a cold plunge causes blood vessels to expand and contract repeatedly, creating a “pumping” effect in the circulatory system. This process can stimulate circulation, help deliver oxygen and nutrients throughout the body, and support recovery after physical activity. Researchers suggest that when used regularly and safely, combining sauna sessions with cold plunges may help reduce inflammation, improve circulation, support metabolic health, and enhance overall resilience to stress.
