A recent scientific review examining heat exposure (such as sauna bathing) and cold-water immersion explains that both heat and cold act as controlled stressors that trigger beneficial adaptations in the body. When the body is exposed to heat, such as in a sauna, blood vessels widen and circulation increases as the body works to cool itself. Cold exposure—like a cold plunge—has the opposite effect, causing blood vessels to constrict and activating the body’s stress-response systems. These temperature-driven responses can influence circulation, inflammation, and metabolic activity, helping the body regulate stress and adapt to environmental challenges. Over time, researchers suggest these adaptations may support cardiovascular health, recovery, and overall physiological resilience.
The research also highlights the potential advantages of contrast therapy, which alternates between heat and cold exposure. Moving from a sauna into a cold plunge repeatedly causes blood vessels to expand and contract, creating what researchers often describe as a “vascular pumping” effect. This process can help move oxygen and nutrients through the body more efficiently while clearing metabolic waste and reducing inflammation after physical activity. Because of these effects, contrast therapy is commonly used to support athletic recovery, improve circulation, and promote both physical and mental resilience when practiced consistently and safely.
