Belonging is part of the dose
New UK research suggests the shared ritual of sauna matters as much as the heat. Why the people you bathe with are part of the benefit.
Cold and cellular clean-up: why age changes the answer
A widely shared study said cold plunges improve the cells' recycling system. It was in young men. The same lab's earlier work shows older men respond differently.
"Cold plunges actually change your cells." You may have seen the headline in 2025. The study is real. The detail matters.
The 2025 study
Researchers at the University of Ottawa published the work in Advanced Biology. Ten healthy young men sat in 14 °C water for an hour a day, seven days in a row.
The team studied autophagy, the process cells use to clear out damaged parts. After the week, autophagy that had initially been disrupted by the cold improved, and signals of cell death fell.
The researchers suggested cold acclimation may be a way to support cellular health, and noted the results apply to young men.
The earlier study
The same Ottawa group had already compared young and older men. In young men, moderate cooling raised autophagy and heat shock protein activity.
In older men, autophagy barely activated, and there were more signs of cell death and inflammation.
What that means
The cellular response to cold appears to change with age. A protocol that looks good in 25-year-olds may not translate to 65-year-olds.
Also, an hour at 14 °C is a demanding laboratory protocol. It is not a home routine and we do not recommend it.
What we would do
- Use cold for what the broader evidence supports: stress, sleep and wellbeing.
- Keep sessions short and build gradually, especially after 50.
- Treat cellular headlines as early science, not a reason to go longer or colder.
Free: The Norge Longevity Guide. Heat, cold and light after 50, with the evidence and the safety rules in one place. Get the guide.
Sources
- King et al., The Effect of 7-Day Cold Water Acclimation on Autophagic and Apoptotic Responses in Young Males, Advanced Biology, 2025
- King et al., Temperature-Dependent Relationship of Autophagy and Apoptotic Signaling During Cold-Water Immersion in Young and Older Males
- University of Ottawa release via EurekAlert
This article is general information, not medical advice. If you have a heart condition, low blood pressure or are pregnant, speak with your GP before using heat or cold.
More from The Research
A sauna does not cancel high blood pressure
Frequent sauna tracked with lower risk in men with high-normal blood pressure, but not once pressure was elevated. Know your numbers.
Six risk factors, 43 per cent of the burden
For Dementia Action Week: the six modifiable risk factors behind a large share of Australia's dementia burden, and where daily habits fit.