Cold water swimming leads to specific adaptations such as improved cold tolerance and possibly improved insulin sensitivity, but does not protect against the general aging process. There are also serious risks such as oxidative stress, DNA damage and elevated blood pressure. The available studies are small, often without a control group, and the findings are mixed.
Cold-water swimming and diving have grown popular in recent years as a method for healthy ageing, but the scientific evidence is currently limited and mixed. The available studies are small, often lack a proper control group, and focus on a wide range of outcomes. Below is a summary of what the research does and does not show.
Research on Korean haenyeo, women who have spent decades professionally diving in cold seawater, shows that at older ages (average 75 years) they have better local cold tolerance in their hands and face than non-diving peers of the same age. They also recover more quickly from cold in the fingers. At the same time, they regulate their body temperature in the cold differently: they lose less heat through the skin rather than burning more energy. However, cardiovascular responses, blood pressure and pain perception in the cold did not differ from those of non-diving older adults. Chronic cold-water exposure therefore leads to specific adaptations, but does not protect against the normal ageing process in general. (PMID 28789677, 28160059, 29098422)
A small study (30 participants, average age 50 years) found that six months of cold-water swimming at least twice a week improved insulin sensitivity in women and lean individuals. This effect was not observed in men or in people with overweight. Because this is a small study without randomisation, caution is warranted when drawing conclusions. (PMID 26966319)
A pilot study in adults with a mean age of 61 years combined cold-water immersion with mindfulness over 20 weeks. Depressive symptoms and anxiety symptoms decreased significantly, with the effect on depression being stronger in participants over 65 years of age. The effect on executive functioning (planning and organising) just fell short of significance. An important caveat: there was no control group that received cold water alone or mindfulness alone, so it remains unclear which component is the active ingredient. (PMID 41283028)
Alongside potential benefits, there are also risks. Repeated diving in cold water (five dives in the Baltic Sea among experienced divers) led to an accumulation of free radicals, DNA damage, fat-breakdown products and the inflammatory protein IL-6, while the body's own antioxidant capacity declined. This oxidative stress and inflammation are also confirmed as a serious risk of regular cold-water diving by review studies. In addition, freediving combined with cold-water exposure strongly raises blood pressure and vascular resistance, more so than exercise or cold alone. This is a relevant risk for people with cardiovascular disease or high blood pressure. (PMID 41223384, 38474303, 35018822)
All findings are based on small observational studies or pilot studies without adequate control groups. No large randomised controlled trials are available. Causal conclusions cannot therefore be drawn. The studies focus on varying forms of cold-water exposure (swimming, diving, immersion) and different outcome measures, which makes comparison difficult.