Cold plunges and saunas are two hot (or rather hot and cold) wellness trends often used in fitness and recovery routines. A cold plunge (or coldwater immersion) involves submerging the body in very cold water (around 50°F or lower) for short periods. It can be as simple as a bathtub filled with ice water or a dedicated cold plunge tank. In contrast, a sauna is a small heated room (typically 150-195°F with low humidity) where one sits to induce sweating. Saunas can be traditional (heated air) or infrared (body-heating panels). Both practices have deep cultural roots and are now studied for their health effects. As Dr. Amy Zack of the Cleveland Clinic notes, a sauna “does seem to show improvement in anxiety,” while sports medicine experts observe that “some people get great relief from using ice baths”.
How Cold and Heat Therapies Affect the Body
Cold and heat each trigger distinct physiological responses. In a cold plunge, icy water causes vasoconstriction (narrowing of blood vessels) and slows metabolic activity. This shunting of blood away from the skin and muscles reduces swelling and soreness. Cold immersion also provokes a brief “cold shock” response: heart rate, breathing, and blood pressure spike sharply, then settle. Hormonal changes occur (e.g., adrenaline release), and the immune system may activate. By contrast, sauna heat causes vasodilation (widening of vessels) and passive cardiovascular exercise. Heart rate rises and sweating begins as the body works to cool itself.
According to Dr. Zack, this heat stress “mimics exercise,” improving circulation and releasing anti-inflammatory compounds. Sauna heat also triggers the release of molecules like BDNF (brain-derived neurotrophic factor) that help relax sore muscles. Both hot and cold therapies engage the nervous system: cold plunges may help restore autonomic balance and improve alertness, while saunas tend to induce relaxation and mental calm.
Benefits of Cold Plunges
Post-Workout Recovery. Evidence suggests that cold plunges can reduce muscle inflammation and soreness after intense exercise. By constricting blood vessels, icy water can flush metabolic waste from muscles and blunt the cascade of tissue damage, leading to less pain and quicker recovery the next day. Many athletes swear by ice baths for this reason. Dr. Dominic King, a sports medicine physician, notes that “some people get physical, mental, and functional benefits” from cold therapy. A small study of soccer players also found that coldwater immersion supported post-sport recovery.
Reduced Inflammation. The cooling effect naturally lowers inflammation. Cold water constricts vessels and can ease swelling in injured tissues. Some users anecdotally report that regular cold plunges help manage chronic inflammatory conditions, though evidence is mixed.
Mental Alertness and Mood. Many enthusiasts report feeling invigorated after a cold plunge. The intense stimulus can sharpen focus and lift mood. In fact, “some people feel that it’s a very helpful mental meditation,” Dr. King says. There are also claims of improved sleep and energy after cold exposure.
Improved Circulation. Alternating cold and warm exposure causes blood vessels to tighten and expand, which may promote vascular fitness over time. However, precise metabolic effects (like weight loss) from cold baths remain unproven.
Potential Risks of Cold Plunges
Cold immersion is generally safe for healthy adults, but it carries risks. Hypothermia and frostbite are the most obvious dangers: prolonged or extreme exposure can dangerously lower core body temperature. One should never plunge into moving or very frigid waters unprepared, and always have warm clothing nearby. Cold shock can also cause rapid breathing or hyperventilation, raising the risk of dizziness or fainting while immersed.
Cardiovascular Stress. Cold vasoconstriction raises blood pressure and heart rate abruptly. The American Heart Association warns that ice baths can dangerously spike vitals, posing a serious risk for people with heart disease, hypertension, or prior stroke. Indeed, clinicians advise that those with cardiovascular risk factors, such as high blood pressure, diabetes, or circulatory problems, should consult a doctor before trying cold plunges.
Nerve or Tissue Damage. Repeated or very cold plunges could cause frostbite or numbness in the skin and nerves. Extended dips also limit muscle control, increasing slip/fall risk. Importantly, for strength athletes, frequent ice baths may blunt the hormonal signals that drive muscle growth: research suggests cold immersion can reduce long-term strength gains after resistance training. (It appears less harmful to endurance adaptations.)
For safe use, experts recommend short durations (start with 13 minutes, up to 5-10 minutes max) and temperatures around 10-15°C (50-59°F) for novices.
Benefits of Saunas
Stress Reduction and Relaxation. Saunas are famous for inducing calm. The heat promotes deep sweating, which many people find mentally soothing. Dr. Zack explains that sauna sessions often provide contemplative, quiet time, “extremely successful in helping to mitigate anxiety, depression, and burnout”. Some studies even link sauna use to better sleep quality.
Cardiovascular Fitness. Regular sauna bathing has measurable heart benefits. The heat raises heart rate (sometimes up to 100-150 bpm), so your body experiences a low-intensity cardio workout. Finnish research famously found that frequent sauna users had significantly lower risk of fatal heart disease and all-cause mortality. Saunas also improve vascular function and can lower resting blood pressure over time. (The effect is similar to moderate exercise and even boosts beneficial anti-inflammatory agents during use.)
Pain Relief and Muscle Relaxation. Heat therapy soothes chronic pain and stiff joints. For example, people with arthritis report less pain and stiffness after sauna sessions.
Neurological and Immune Effects. Emerging evidence suggests regular sauna use may support brain health. One large study found that frequent sauna bathing was associated with a lower risk of Alzheimer’s and dementia. The physiological reason might involve heat-induced neuroprotective pathways, though more research is needed.
Potential Risks of Saunas
Saunas are safe for most healthy people, but precautions apply. Dehydration and overheating are the main concerns. Because saunas make you sweat profusely, it’s important to drink water before, during, and after to replace fluids.
When incorporating saunas or cold plunges into your routine, it’s wise to consult a clinician or trained specialist. Sports medicine doctors, physical therapists, and other providers can tailor protocols safely to your health status. For example, an exercise physiologist might advise on proper timing and duration based on your training goals. Nurses and other healthcare providers studying integrative health (for instance, through an ADN to NP program) also learn about these modalities and can guide patients in balancing risks and benefits.
