New research from University College London and leading longevity institutes reveals that the biological mechanisms behind women’s survival advantage are the very same ones activated by regular sauna use and cold water immersion. This is not a wellness trend. It is evidence-based biology.
It is one of the most consistent findings in all of medical science: women outlive men. Across every country studied, every historical era examined and virtually every culture on record, women live longer. In the UK, the average woman lives to 83 while the average man lives to 79 – a four-year gap that persists despite improvements in men’s health habits in recent decades.
Researchers at the University of Alabama at Birmingham, who have spent decades studying ageing across species, describe it as one of biology’s most reliable patterns. “Women always survive better than men,” says Professor Steven Austad, who co-authored a landmark review in Cell Metabolism. “When times are good, when times are bad – it doesn’t seem to matter.”
But here is what is new, and what makes this conversation suddenly urgent for any woman paying attention to her long-term health: scientists are now identifying the precise biological mechanisms behind this survival advantage. And those mechanisms are exactly what sauna bathing and cold water immersion activate most powerfully.
Why women live longer: what the biology actually shows
For years, oestrogen was assumed to be the primary explanation. But that theory has a significant problem: the female survival advantage appears even in infants and young children, long before meaningful hormonal differences exist between the sexes. Hormones alone cannot explain it.
The current scientific consensus points instead to four interconnected biological mechanisms:
- Mitochondrial efficiency. Women generally carry more mitochondrial DNA and show better cellular respiratory function, meaning their cells convert oxygen and nutrients into energy more efficiently – a process directly linked to slower biological ageing.
- Slower immune ageing. Stanford University research shows that women’s immune systems age more slowly than men’s, with men experiencing more severe inflammation spikes as they get older – a process called immunosenescence that accelerates disease progression.
- Lower chronic inflammation. Systemic inflammation is now understood to be the common mechanism behind cardiovascular disease, dementia and cancer. Women show consistently lower inflammatory markers across most of their lifespan.
- Better cortisol regulation. Chronic cortisol elevation – more common in men – is directly associated with accelerated biological ageing, reduced immune function and poorer cardiovascular outcomes.
What makes this so compelling is that these are not abstract or remote biological phenomena. They are measurable, responsive systems. And they respond powerfully to deliberate heat and cold exposure.
UCL’s landmark study: cold water immersion and women’s health
In January 2024, researchers at University College London published findings that have since become one of the most cited studies in UK wellness medicine. Led by Professor Joyce Harper at the UCL EGA Institute for Women’s Health, the study surveyed 1,114 women – 785 of whom were experiencing menopause – on the effects of regular cold water immersion on their health and wellbeing.
| UCL STUDY 2024 – 785 MENOPAUSAL WOMEN – KEY FINDINGS | |||
| 46.9 %reported significant reduction in anxiety | 34.5 %experienced fewer mood swings | 31.1 %reported improvement in low mood | 30.3 %found relief from hot flushes |
Perhaps most tellingly, 63.3% of the women in the study said they used cold water specifically to relieve their menopausal symptoms – suggesting that many women had already intuited the connection long before the science caught up.
| “Cold water has previously been found to improve mood and reduce stress in outdoor swimmers. Our study supports these claims, while also highlighting how the activity can be used to alleviate physical symptoms such as hot flushes, aches and pains.”Professor Joyce Harper, UCL EGA Institute for Women’s Health, January 2024 |
The British Sauna Society has highlighted similar observations. Scotland-based GP and lifestyle physician Dr Kath Jones uses sauna strategically in her wellness retreats for female healthcare professionals, noting that it immediately supports relaxation and reduces what she describes as physiological and social barriers. A 2026 study published in ScienceDirect went further, linking sauna culture directly to NHS preventive care goals and noting that it aligns closely with the NHS’s social prescribing agenda.
The connection: how sauna and cold plunging reinforce women’s biological advantages
The parallel between what explains women’s longevity and what sauna and cold therapy activate is not a coincidence. It is the same biology, approached from two directions.
| BIOLOGICAL FACTOR | WHAT SAUNA & COLD PLUNGING DOES | OUTCOME |
| Mitochondrial health | Cold exposure triggers mitochondrial biogenesis – the creation of new mitochondria in cells (Advanced Biology, 2024). Sauna activates heat shock proteins that maintain mitochondrial function. | Greater cellular energy efficiency, slower biological ageing |
| Immune function | Regular sauna increases white blood cell production and activates heat shock proteins (HSP70, HSP90) that repair damaged proteins at cellular level. | Stronger immune response, reduced vulnerability to age-related disease |
| Chronic inflammation | Cold water immersion reduces pro-inflammatory cytokines (IL-6, TNF-alpha) and increases anti-inflammatory IL-10. Effect is both acute and cumulative. | Direct suppression of the systemic inflammation that drives ageing |
| Cortisol regulation | Regular sauna measurably lowers baseline cortisol. Cold plunging produces a brief acute spike followed by sustained reduction in chronic stress hormones. | Lower biological ageing rate, improved cardiovascular and cognitive health |
A 2025 study published in Scientific Reports examined the acute effects of Finnish sauna bathing and cold water immersion specifically in normotensive women, finding significant positive cardiovascular responses – confirming that the landmark effects seen in the Finnish KUOPIO cohort extend meaningfully to female physiology.
The menstrual cycle matters: how to adapt your practice
One area where the science is beginning to catch up with what many women already sense instinctively is the relationship between the menstrual cycle and thermal therapy. Women’s bodies do not respond identically to sauna and cold exposure throughout the month.
- Follicular phase (days 1–14): Oestrogen is dominant and the body tends to be more resilient to intense thermal exposure. Generally a good time for cooler temperatures in cold plunging and longer sauna sessions.
- Ovulation: Core body temperature rises naturally. Staying well hydrated and keeping sessions slightly shorter is advisable.
- Luteal phase (days 15–28): Progesterone dominates and some women find they are more sensitive to extreme cold. Warmer cold plunge temperatures and shorter sessions often work better.
- Menstruation: Many women find sauna bathing particularly effective for pain relief during menstruation. Others prefer to rest. Listening to the body is the evidence-based recommendation.
Dr Jolene Brighten, a board-certified OB-GYN and hormone specialist, notes that sauna and cold plunging function as hormetic stressors – controlled, short-lived stressors that build physiological resilience over time, fundamentally different from the chronic stress that depletes it.
Swedish Cold: bringing professional-grade recovery home
Understanding the science is one thing. Translating it into a consistent daily practice is another – and that is where access becomes the deciding factor. The single biggest barrier between women and the health benefits described above is not motivation. It is logistics.
Getting to a spa or gym, working around opening hours, sharing facilities with strangers and scheduling sessions around a busy life means that, for most women, thermal therapy remains an occasional indulgence rather than a true recovery ritual. And as the research is clear: occasional is not enough.
Swedish Cold is a Scandinavian premium recovery and wellness brand specialising in cold plunge systems, outdoor saunas and infrared saunas – designed to bring professional-grade recovery home without any compromise on quality, hygiene or performance. Their clients include Sheraton Hotels, Strawberry Hotels, Hotell Östersund & Spa and Fit Club Mallorca.
The philosophy is straightforward: the recovery tools used by elite athletes and five-star spas should be available at home, built to the same standard, delivered ready to use and designed to last for decades. Every product is CE-certified and WiFi-controlled.
| SWEDISH COLD – PRODUCT RANGE | |
| Cold Plunge – Generation 5 | The only consumer system that forms ice internally and holds 0–3°C stable throughout your session. ±0.9°F temperature accuracy. The choice of Sheraton Hotels, Strawberry Hotels and leading European wellness centres. |
| Outdoor Sauna | Freestanding, key-ready saunas in carbonised white pine. WiFi-controlled, no planning permission required and ready to use on the day of delivery. |
| Hybrid Sauna (Indoor) | Traditional and infrared heat in one freestanding indoor unit. Run either mode – or both simultaneously. Fits a dedicated room, garage or basement. Key-ready for 4–6 people. |
| Infrared Sauna | Deep-penetrating infrared heat at lower temperatures. Ideal for muscle recovery, stress reduction, sleep optimisation and perimenopausal symptom relief. |
The complete contrast therapy protocol – infrared sauna for deep warmth, traditional sauna for intense Nordic heat, cold plunge for the dopamine and norepinephrine surge – is the same sequence offered at the finest spa facilities in Scandinavia. At home, on your schedule, with no booking required.
Learn more at swedishcold.com
Longevity is not a destination. It is a daily practice.
The Max Planck Institute’s 2025 analysis – the most comprehensive study of sex differences in lifespan ever conducted, examining 1,176 species – confirmed what decades of human research had already suggested: the female survival advantage is deeply rooted in biology, consistent, universal and not going away.
But biology is not destiny. The same mechanisms that give women a natural advantage in longevity – mitochondrial efficiency, immune resilience, inflammation control and stress regulation – are precisely the mechanisms that deliberate, regular thermal therapy strengthens and amplifies.
The UCL research, the British Sauna Society’s clinical observations, the JAMA cardiovascular data and the emerging science on cold exposure and cellular resilience all point in the same direction. The women who will age best are not simply the ones born with the right biology. They are the ones who show up consistently.
The biology is already working in your favour. The question is whether you give it the tools to go further.
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