Cold plunging involves brief immersion in cold water, often below 59°F, triggering a significant physiological response. When exposed to cold, the body prioritizes core temperature maintenance through peripheral vasoconstriction, constricting blood vessels in the extremities and skin. This survival mechanism shunts warm blood toward vital organs but cools peripheral tissues considerably. Rewarming must be controlled and gradual to prevent “afterdrop,” where the body’s core temperature continues to decline even after exiting the water.
Immediate Post-Plunge Actions
The moment you exit the cold water, the first priority is to stop further heat loss through passive external measures. Water conducts heat away from the body about 25 times faster than air, so removing all wet clothing, including swimwear, is paramount. Evaporative cooling from wet skin and fabric can continue to chill the body rapidly, making immediate and thorough drying necessary.
Use a soft towel to gently pat the skin dry, focusing on the head, neck, hands, and feet, as these are common sites of significant heat loss. Once dry, quickly put on warm, loose, and layered clothing. Covering the head with a warm hat is highly recommended, and a windproof outer layer is beneficial if you are outdoors.
Layering helps trap heat and allows for easy adjustment as your body temperature stabilizes. Focus on wool or synthetic fabrics, which retain warmth even if slightly damp, and avoid cotton, which holds moisture against the skin. Transitioning to a warm, dry environment, such as a heated room or running car, should happen immediately after applying initial layers to shield the body from the cold ambient air.
Safe Internal Heat Generation
Once initial heat loss is arrested, the next step involves encouraging the body to generate its own heat gradually from the inside out. This is accomplished by engaging in gentle, low-impact movement, which helps restore circulation without causing a sudden rush of cold blood back to the core. A slow, sustained walk, light stretching, or arm circles are effective ways to activate large muscle groups and produce metabolic heat.
The movement should remain mild and not intense, as rigorous exercise immediately after a plunge can divert blood flow to the working muscles too quickly. This rapid vasodilation can push cooled blood from the periphery back to the core, which can unexpectedly lower core temperature further, exacerbating the afterdrop effect. The body may start to shiver, which is a natural, highly effective mechanism for generating heat, as muscle contractions can increase heat production up to five times the resting rate.
Sipping a warm beverage can help to raise the core temperature gently from the gastrointestinal tract. Herbal teas or simply warm water are ideal choices, ensuring the liquid is warm, not scalding hot, to avoid shocking the system. Fast-acting carbohydrates, such as a small piece of fruit or a snack, can provide the necessary fuel to support the body’s metabolic effort to rewarm itself and sustain the shivering response.
Avoiding Common Rewarming Mistakes
One of the most frequent errors after a cold plunge is seeking immediate, intense external heat, such as jumping into a hot shower, a sauna, or a hot tub. This rapid application of heat causes peripheral blood vessels to dilate almost instantly, leading to a sudden drop in blood pressure. The quick expansion of blood vessels can cause lightheadedness or dizziness, creating a risk of fainting or falling.
Furthermore, this rapid vasodilation forces the cooled blood that was trapped in the extremities back toward the body’s core. This influx of cold blood actively drops the core temperature further, intensifying the afterdrop phenomenon. It is safer to wait at least 15 to 20 minutes and achieve stable warming through gentle movement and dry clothing before considering a warm, not hot, shower or bath.
Another mistake is consuming alcohol immediately after exiting the water. Alcohol acts as a vasodilator, opening blood vessels near the skin’s surface, which creates a false and misleading sensation of warmth. This peripheral vasodilation actually accelerates heat loss from the body, driving the core temperature down and significantly worsening the risk of hypothermia. Avoiding caffeinated beverages is also recommended, as they can interfere with the body’s natural shivering response.