Doctor Rhonda Patrick here. In my last video on hyperthermic conditioning, I suggested that regular sauna use may improve athletic endurance, prevent muscle atrophy, improve insulin sensitivity, increase neurogenesis, the growth of new brain cells, improve learning and memory, and may also increase longevity. Today we're going to pick up where we left off. Longevity. My last video was a little prescient on this topic because recently the Journal of JAMA Internal Medicine published a study that showed that sauna use was was in fact associated with longevity.

The study recruited over 2000 middle aged men and investigated the frequency of sauna use with sudden cardiac death, fatal coronary heart disease, fatal cardiovascular disease and all cause mortality, including cancer, over the course of 20 years. Let's talk about what the study found. The study found that fatal Cardiovascular disease was 27% lower in men that used asana two to three times a week and 50% lower in men that use the sauna four to seven times a week compared to men that only use the sauna once a week. Moreover, the study found that men that use asana two to three times a week had a 24% reduction in all cause mortality and men that used asana four to seven times a week had a 40% reduction in all cause mortality compared to men that only used the sauna one time a week.

But of course, one sauna may vary from the next. So let's talk about one of the important parameters used in this study. Temperature. The average temperature of the dry saunas used in the study were hot 79 degrees Celsius or 174 degrees Fahrenheit, often used with a splash of water poured over hot rocks to increase the humidity for a duration of up to or exceeding 20 minutes. This means that the results may not be directly applicable to hot tubs, steam rooms and infrared saunas, which often operate at a lower temperature. Now that doesn't mean that there's no merit to using hot tub steam rooms and and infrared saunas. It just means that there are subtle differences if you're comparing them to the hot and dry finish saunas that were used in this study.

Some of the positive benefits of sauna use on heart health may be due to similar effects that regular physical exercise has on heart health. Using the sauna at a moderate level can increase the heart rate to 100 beats per minute and a more intense sauna session can increase heart rate to 150 beats per minute. Just in case you didn't know, that's fast and and the latter corresponds to moderate intensity Physical exercise. Long term sauna use has been shown to improve blood pressure, endothelial function and ventricular function. Now, let's talk about longevity. After all, that was the most striking finding of this study. I think there are a couple of good molecular explanations that can explain how sauna use could influence longevity.

First, we'll talk about a topic that we've discussed previously. Heat shock proteins, also known as HSPs. Heat stress from using the sauna and also to a lesser degree, exercise, can activate the expression of genes that make more heat shock proteins. Heat shock proteins have many important functions inside the cell. One important function is to make sure that proteins which do all the biological work inside the cell maintain their proper three dimensional structure when under stress. This is whether we're talking about stress from heat or or stress from normal aging, from injury, or from UVB radiation, for example. The three dimensional structure of the protein is very important for its function as well as for the longevity of the protein itself.

Just normal metabolism and normal immune function. In other words, just living creates reactive byproducts called reactive nitrogen and reactive oxygen species which damage the proteins inside of your cell. This damage disrupts the three dimensional structure of the proteins and the function of this protein so that it's no longer able to do the it's supposed to do. Not only does this damage disrupt the function of the protein, but it also leads to protein aggregation. Protein aggregation is found in cardiac diseases such as heart failure, in atherosclerosis and cardiomyopathy, and is also commonly found in neurodegenerative diseases such as Alzheimer's disease, Parkinson's disease and Huntington's disease.

Since we know that heat shock proteins are awesome because they help us resist stress, both of the exceptional varieties such as tissue injury, and also the normal varieties such as normal aging, perhaps it's not so surprising that heat stress increases the lifespan of flies and worms by 15%. And this has been shown to be dependent on heat shock proteins. Another tidbit of information that suggests heat shock proteins may be associated with human longevity comes from the fact that a gene polymorphism that increases the expression of more heat shock proteins is associated with being a centenarian, that is living to be 100. That said, heat shock proteins aren't the only protein we should be looking at when trying to investigate the effects of heat stress on longevity.

Another molecular pathway we should be looking at is Foxo3. While I have mentioned heat shock proteins in my last sauna video, I did not mention Foxo3. I have however, mentioned Foxo3. In other videos and other presentations, Foxo3 is associated with longevity. In fact, humans that have a gene polymorphism that make more FOXO3 have have up to a 2.7 fold increased chance of living to be a centenarian. Also, mice that make more Foxo3 increase their lifespan by 30%. So how does Foxo3 accomplish this? Foxo3 is a master regulator of many different genes. When it's on, it turns on many different genes that make your cells more resilient to a variety of different stresses that occur with age.

Many of the genes that Foxo3 turn on happen to decrease with age, so it's really good to boost their expression. One particularly important type of stress that Foxo 3 protects against is DNA damage. The same type of reactive byproducts from normal metabolism and normal immune function that damage proteins also damage DNA. DNA damage can lead to a mutation, and when a damaged cell has a mutation, it can replicate and can lead to cancer. FoxO3 increases the expression of genes that are involved in DNA repair so that the damage is repaired and never forms a mutation. Foxo 3 also increases the expression of genes that kill damaged cells so they can't form cancer.

Foxo3 also makes cells more resilient to damage by increasing the expression of genes that combat this damage, including antioxidant genes, which are much more potent than dietary antioxidants. In addition, when cells become damaged, or when telomeres become critically short, cells undergo senescence, which means they are not dead, but they're not alive either. Rather, they just sit around and they secrete pro inflammatory cytokines and pro inflammatory molecules that damage other nearby cells, creating this vicious cycle of pro inflammatory cytokine production. Well, Foxo 3 increases the expressions of genes involved in autophagy, which means the damaged cell will will eat itself instead of sitting around secreting pro inflammatory cytokines.

FOXO3 also increases the expression of genes that are involved in immune function, which declines with age, so that your immune cells can fight off viruses, bacteria and cancer cells better. Foxo3 increases the expression of genes involved in metabolism and stem cell function, just to name a few. Please, somebody pass me more foxo3. So, in summary, sauna use was associated with longevity. The more frequent the sauna use, the greater the effect on longevity. Heat stress, such as using the sauna, activates heat shock proteins and this has been associated with increased lifespan in worms and flies. Heat shock proteins also protect against one of the types of stress associated with aging.

Heat stress also activates one of the well known longevity genes FOXO3A, which happens to protect against a variety of different cellular stresses that occur with age. It comes as very little surprise that using the sauna regularly may come with some genuine health benefits that encompass longer life. As for me, I'm going to continue hitting the sauna every chance I get. Dr. Rhonda Patrick, over and out.