Finland’s ancient tradition of sauna bathing, often paired with a bracing dip in icy water or a roll in the snow, is capturing global attention. What might seem like an extreme practice to outsiders is deeply embedded in Finnish culture – so much so that sauna bathing is recognised on Unesco’s Intangible Heritage List. With an incredible 3.3 million saunas for a population of 5.5 million, it’s an accessible and integral part of life across generations in Finland.
But beyond the cultural significance and the undeniable rush it provides, what does science actually say about the health benefits of this intense hot-and-cold ritual?
For those who embrace it, like this author who describes the piercing pain of Arctic river water after intense sauna heat, the sequence can feel profoundly invigorating. Stepping from the steamy dark of an 85°C (185°F) sauna into near-freezing waters can transform pain into an almost “icy hug,” leaving the air outside feeling surprisingly warm. This hot-cold cycle is known in sports medicine as contrast therapy, and the experience can leave participants feeling energized and happy. It’s a ritual enjoyed by millions of Finns, and its popularity is now spreading far beyond Scandinavia.
How Your Body Reacts to the Extremes
Understanding the potential health impacts requires looking at how the body responds to these rapid temperature shifts.
When you enter a hot sauna, your body temperature slowly rises (perhaps from 37°C/99°F to 39°C/102°F). Your blood vessels widen (vasodilation), you begin to sweat, and your blood pressure tends to decrease. Conversely, plunging into cold water triggers a sharp, immediate reaction called “cold shock.” Your blood vessels constrict (vasoconstriction), and your heart rate and blood pressure surge.
However, research indicates that regular exposure to cold water can actually lead to a remarkable adaptation: a decrease in average heart rate and blood pressure over time. Both hot and cold exposure also trigger hormonal responses. Sauna heat can increase endorphins (natural mood boosters), growth hormone, and hormones that respond to physiological stress. Cold immersion releases neurotransmitters like norepinephrine (increasing alertness and energy) and raises levels of serotonin, cortisol, dopamine, and endorphins, all crucial for mood and stress regulation.
Potential Science-Backed Health Benefits
While many studies on sauna and cold bathing effects lack the rigor of large-scale randomised controlled trials (RCTs), significant observational research, particularly from Finland, offers compelling insights.
Cardiovascular Health: Extensive observational data from a 20-year study tracking over 2,600 middle-aged and older Finnish men suggests a strong association between frequent sauna use and reduced risk of high blood pressure, heart disease, and sudden cardiac death. Researchers propose that the rapid dilation and contraction of blood vessels during the hot-cold transition may train the cardiovascular system, potentially reducing arterial stiffness and helping manage factors like inflammation and stress. Furthermore, a randomised controlled trial demonstrated that combining sauna sessions with exercise three times a week for eight weeks resulted in a substantial average reduction of 8 mmHg in blood pressure compared to exercise alone.
Brain Health & Cognitive Function: An observational study from 2017, also following over 2,300 men for two decades, found that more frequent sauna bathing was inversely associated with the risk of dementia and Alzheimer’s disease. Men who used a sauna 2-3 times weekly had a 20-22% lower risk than those using it once a week. This benefit increased significantly with more frequent use (4-7 times/week), showing a 65-66% lower risk. It’s important to note that this was an observational study, meaning it shows a correlation but doesn’t prove direct causation. The findings could potentially reflect other lifestyle factors common among frequent sauna users, but they strongly suggest an effect worthy of further investigation. Observational research also hints at potential benefits for reducing the risk of mental disorders.
Mental Wellbeing & Stress Management: Beyond physiological changes, the practice offers psychological benefits. Anecdotal accounts highlight the sauna ritual as a source of calm and structure, even during difficult times. The combination of heat, scent, and darkness can induce relaxation. Regular sauna use has been shown to reduce chronic tension headaches. Psychologically, the sauna is seen as a unique space where social norms are temporarily suspended, fostering connection and perhaps even personal transformation by enduring extremes together. Cold water immersion also appears to boost confidence and self-esteem, helping individuals learn to tolerate discomfort, which may improve stress coping in other areas of life. Studies of winter swimmers report reduced tiredness and improved mood.
Potential Risks and Safety Considerations
Despite the promising potential benefits, it’s crucial to be aware of the risks associated with sauna and cold water practices, particularly the combination.
Cardiovascular Strain: The rapid shift from heat to cold can intensely affect circulation. For individuals with pre-existing cardiovascular disease, rapid cooling is associated with risks like heart arrhythmia. While rare, serious incidents including heart attacks and deaths after cold water immersion post-sauna have been reported, often linked to alcohol consumption or undiagnosed health conditions.
Heat Exposure Risks: Prolonged sauna sessions can lead to heatstroke, which can be severe and require hospitalisation.
Cold Water Risks: Cold water swimming carries inherent dangers including cold shock (which can lead to incapacitation), hypothermia (if immersed too long), and dangerously high blood pressure, especially in those with underlying heart conditions.
Medical experts strongly advise caution and recommend consulting a healthcare professional before starting such practices, particularly if you have any existing health conditions.
Safe Practices & Acclimatization
To minimise risks and maximise potential benefits, gradual adaptation is key. For cold water exposure, experts suggest starting slowly and progressively using colder water over about two weeks to allow the body to acclimatise. Don’t overdo it – stay as long as it feels right. For potential mental wellbeing benefits from cold water, research suggests aiming for temperatures between 0-10°C (32-50°F) for at least 30 seconds, two or three times a week, once acclimatised.
Supervision is recommended during cold water swimming in case difficulties arise.
Looking Ahead
While existing research is encouraging, particularly the large observational studies from Finland, the scientific community notes the need for more rigorous randomised controlled trials to definitively establish cause-and-effect relationships and long-term impacts, especially concerning years of ice bath practice.
For many, like the author who began this journey seeking scientific validation, the practice remains a deeply rewarding ritual. Knowing there is growing scientific support for its potential effects on cardiovascular health, brain function, and mental wellbeing adds a layer of understanding to the profound physical and mental sensations it provides.
All content within this article is provided for general information only and should not be treated as a substitute for the medical advice of health care professionals.
References
- https://www.bbc.com/future/article/20250520-are-saunas-and-cold-plunges-good-for-your-health
- https://explore-mag.com/the-way-of-the-wolf-canoeing-saunaland/
