A Hot Bath (Sauna) is as Good as ExerciseJune 13, 2021
A Hot Bath is as Good as Exercise
The Romans did it. They built the hot baths at "Bath" 2000 years ago, trying to civilize those feisty Celts. Queen Victoria took a dip. The Japanese do it. The Fins won't let you build a house or an apartment without a sauna. American's have hot tubs galore. Is there anything to this idea of a "hot bath" other than hedonic adaptation? Well yes. You feel better when you get out of it, and intuitively, you want to do it again. Are there real health benefits?
Well, yes! And the evidence is accumulating as to the exact mechanisms and physiology. We have reported on the epidemiology of saunas on heart disease. In a study published in JAMA Internal Medicine in 2015 from Finland, 2300 men were followed for 20 years and their sauna use was recorded. Over those 20 years, once-a-week sauna resulted in a 49% death rate, compared with 38% of those going two to three times a week and just 31% of those who went four to seven times a week. Frequent visits to a sauna were also associated with lower death rates from cardiovascular disease and stroke. Now, compare that to the 5 days of life extension you get with taking statins. Hmmm....And that was for only 14 minutes.
The Review article on the physiology of "hot baths" is pretty good. The take-home message is that all the markers of metabolic stress that come out in the "metabolic syndrome" get better with sauna. As they do with exercise. Your blood pressure actually goes up in a hot bath. Your heart rate increases. Your arteries have to stretch and dilate to deliver more blood flow to dump the heat. All those mechanisms are the same as what's going on with exercise, without the exercise. There are even reports diving down to endothelial dysfunction, the core root problem of vascular disease. After the sauna, your blood pressure is down 7/5 mm of Hg. That's as good as a blood pressure pill, without the pill. And the same salutary effect is seen with stroke.
The key takeaway is around the idea of "hormesis" which is essentially the rebound benefit from the temporary stress. Exercise is a stress. You deplete your energy supply and force your mitochondria to use up their ATP and start burning fat. If you push to the point of failure, you are just one molecule of ATP short of collapse. You turn on repair and resilience genes. Acute heat exposure is the same temporary "stressor". The mechanisms all go down to the inner workings of the cell. We now know that endothelial dysfunction in the arteries is the first step of developing vascular disease, our 21st century nemesis. Vascular disease can't get started without plasmalogen deficit. It appears that "hot baths" reverse that.
www.What will Work for me. Isn't this interesting? The Fins are onto something here. They have proven the epidemiology of benefit from saunas and are now leading the way in exploring the physiology so that we get more insight into what's going on and how we can improve on it. The question arises, can we get the same effect with sun-bathing? Again, heat exposure for a brief period of time. Now, we are all distracted by the sunburn and melanomas, but is there a similar "hormesis" effect? With this summer's record-breaking heat, I feel we are all getting our saunas. It's only 14 minutes you need. More is likely a bit better.
References: The Conversation, Int Jr Envir Res Pub Health, Jama Internal Medicine, J Hum Hypertension, Neurology,
1. How long a sauna do I need to get some measurable benefit? Answer: 14 minutes
2. And just how often do I have to do that? Answer: just like exercise, 4 or more times a week is best, but 1-2 a week is better than none.
3. Compared to statins, how much benefit do I have on vascular disease? Answer: well, statins add 5 days to your life. You reduce heart attack deaths by over a third with saunas. It's apples to oranges comparisons, but it feels like some 10 fold better results.
4. If I sauna and exercise, what happens then? Answer: you will have to arrange for some other way to die than heart disease, at some later date.
5. How do I get a sauna? Answer: You can buy one for your home for about $ 1800 or so and get a kit to make an infrared sauna.