- ATE and greater longevity: A recent study published in JAMA Internal Medicine showed that thermal treatments are associated with greater longevity. The study of over 2,000 middle-aged men in Finland found that fatal cardiovascular disease was 27% lower for men who used the sauna 2 to 3 times per week and 63% lower in men taking 4 to 7 sauna sessions each week!(63)
- Increased HSPs: HSPs and variations in the HSP70 gene can also help provide longevity and anti-aging benefits. In flies and worms, heat exposure has been shown to increase lifespans by as much as 15% (36,37,37.5, 38,39) A growing body of literature supports the role of HSPs in heat adaptation which allows organisms to perform work in high-temperature environments.(24) Other animal studies have shown that chronic exercise enhances HSP70 accumulation in skeletal muscle.(61) Exercise in heat has also been shown to increase concentrations of HSPs, which may illustrate a cellular adaptation of heat acclimation in humans. (23)
- Foxo3 Gene*: Another molecular pathway that may explain how heat exposure can improve longevity is a gene that is associated with longevity known as Foxo3*. Foxo3 is one of the four mammalian Foxo genes, and it is activated by heat stress. Humans with a polymorphism that makes more of this gene have up to a 2.7fold increased chance of living to the age of 100.(97) In mice, having more of their homologous version of this gene can extend their lifespan by up to 30%.(96) The mechanism by which Foxo3 increases longevity has to do with the fact that it is a master regulator of many different genes. When the Foxo3 gene is “on”, it increases the expression of a number of genes that increase resistance to many of stressors that occur with aging. Many of the genes that foxo3 increases typically decrease with age, so it is important for longevity to boost their expression.(97) One critically important stress that Foxo3 protects against is DNA damage. The same type of reactive byproducts (from normal metabolism and immune function) that damage proteins in the cell also damage DNA.(97) DNA damage often leads to mutations. Damaged cells with mutations often replicate to form cancer. Foxo3 increases the expression of DNA repair genes that help prevent cell mutations.(97) Foxo3 also increases the expression of genes that kill cell damaged cells so that they do not become cancer cells.(97) Foxo3 makes cells more resilient to damage by increasing the expression of genes that combat damage such as antioxidant genes which prevent the damage from reaching the cell. Finally, Foxo3 increases the expression of genes responsible for immune function (which generally declines with age). Boosting the immune system enables us to combat bacteria, viruses, and cancer cells more effectively which leads to longer and healthier lives.(97)
*Note: See appendix for additional information.