Posted on 27 August 2021
Longevity briefs provides a short summary of novel research in biology, medicine, or biotechnology that caught the attention of our researchers in Oxford, due to its potential to improve our health, wellbeing, and longevity.
Why is this research important: Multiple studies in the past have found that regular sauna use is associated with a reduced risk of multiple chronic diseases, including cardiovascular disease and neurodegenerative diseases. It has been suggested that exposure to high temperatures may be a form of hormesis, meaning in this context that it is harmful in high quantities but beneficial with limited exposure. If this is correct, sauna use could be an effective and relatively easy way to extend healthy life expectancy.
What did the researchers do: In this paper, researchers review and summarise the evidence for the health benefits of sauna use and its potential mechanisms.
Key takeaway(s) from this research: The authors argue that evidence in favour of the benefits of sauna use is compelling, in particular the findings of large follow-up studies suggesting that there is a dose-dependant relationship between sauna use and reduced morbidity and mortality (that is to say, the more you frequent the sauna, the less likely you are to experience illness or death). In one such study, using a sauna 2-3 times a week was associated with a 27% reduction in cardiovascular disease mortality among middle-aged males.
It is suggested that raising body temperature induces some of the same physiological responses as exercise, leading to cardiovascular benefits. High temperatures also activate a family of proteins called heat shock proteins, which protect against cellular stress, and may protect against the misfolding and aggregation of proteins, which is suspected to be a driver of the ageing process and of specific diseases like neurodegenerative diseases.
One of the problems with evidence in favour of sauna benefits is that most large studies are observational, meaning they follow the health of participants who are using saunas of their own accord. Since the kinds of people who use saunas are more likely to be wealthy and may be more likely to participate in other healthy activities, while those whose health is already poor may be unwilling or unable to use saunas, these confounders need to be accounted for. Randomised trials (in which participants are randomly assigned sauna use or no sauna use) have also suggested beneficial effects for saunas, but these studies were much smaller. However, the authors argue that the existence of strong dose-dependant relationships between sauna use and health mean that sauna use probably does have real benefits.
Sauna use as a lifestyle practice to extend healthspan: https://doi.org/10.1016/j.exger.2021.111509