[nsbk]

I recently listened to a podcast about the benefits of sauna or deliberate heat exposure and the gist is that if you get your core temperature at about 39 degrees celsius your cardiovascular system is working comparably hard to light exercise.

My take is that your heart and lungs are working out, even if your body is not. Do you get the same benefits as going for a run or bike ride for a comparable amount of time? no, since your limbs don't get fit, but your heart and lungs do.

[shmel]

Not saying you are wrong, but I'd like to see some evidence on that. Just because your heart is pumping faster doesn't mean your cardio fitness is getting better. Otherwise we could all just snort cocaine and skip the gym. Alcohol does that too, anyone with a fitness tracker can check that.

[asdfman123]

Athletes already know the answer from years of cultural knowledge, research, and firsthand experience. No, it doesn't make your cardio fitness meaningfully better. If you did sauna training for years and then tried to ramp up for a marathon, you'd be hopelessly out of shape.

Endurance athletes obsessively track VO2 max, basically your body's ability to consume oxygen during workouts, and it certainly doesn't improve with sauna training.

It's like asking "if you only did puzzles, would you be smarter?" Well, in a way, yes, but if you actually want to compete with someone with a good education you have to read.

Same with physical exercise. It puts a lot of different stresses on your body that saunas don't. The question isn't "do saunas make you physically fit," because they don't. The question is "for people who don't want to exercise, does sauna training alone meaningfully extend your healthspan?" I'm guessing the answer is "a little but not enough," but I'm not sure.

[monkpit]

You’ve honed in specifically on VO2 but what about cardio health in general? Like light treadmill, not like a demanding marathon.

[asdfman123]

Cardio of course is short for "cardiovascular system," which consists of a whole lot of moving parts. Saunas improve some parts of it but certainly not all of it.

Will fixing up your radiator fix your car? Maybe, if the radiator was the problem, but there's a lot of other stuff inside a car to work on, too.

Your body evolved under the expectation that it would be stressed in numerous different ways, but those stressors can all be avoided in the modern era. If you want to most reliably recreate those stresses you need to do cardio and resistance training.

[barnabyjones]

Without exercise, you won't burn ATP and thus won't increase mitochondrial count.

[nradov]

A light treadmill session won't do much to improve your cardiovascular system health either. I mean it's better than nothing but don't expect too much.

[xtracto]

Moreover, I'm from a very hot and humid tropical region. Its normal to ne 40°C with 80% humidity there. And you dont see people having better health or longevity (Yucatan peninsula) .

[smileysteve]

40° internal body temperature is not the same as 40° weather.

Yucatan is not the same as Dubai in Summer.

Your body is under heat shock trying to keep up in a Sauna (that isn't considered warm until 60°). Versus a healthy body CAN keep up in 40°.

The Yucatan equivalent of a Sauna is more like doing hard labor on a roof on a sunny day with no breeze.

[Tor3]

Right, it's just that a sauna at 60 degrees is not warm, it's cold. Take a shower, go into the sauna at 60 degrees C, and it'll feel cold. Nothing happens in a sauna until you're getting near 80, and it's much better if you go somewhat higher (90 or more for active users). 60 is when a sauna will be closed off in public baths because there's a technical problem somewhere.

[actionfromafar]

But that would be like exercise all the time which may not be optimal. (Not saying the theory holds that sauna equals exercise, but if it does, sauna all the time may not be great. Plus, there may be other confounding factors with living in various locations.)

[Insanity]

The great but not super healthy Mexican diet might offset the potential heat exposure benefits! Although I’m basing that on the diet of my Monterrey-based in-laws, not sure how different Yucatan is.

[xtracto]

LOL, Monterrey diet is healthy compared to the diet in the Yucatan peninsula.

Tamales, Cochinita (roasted pork with herbs), salbutes, trancas. Everything of course cooked in Lard. With CocaCola on the side.

So yeah, that's a strong point.

[cpursley]

Lard is fine as is pork, it’s the sugar and carbs.

[mminer237]

Edit: I posted this accidentally when editing without noticing. Hypertrophy isn't necessarily a bad thing. I thought I was discarding the comment cuz I realized I was out of my depth. whoops

Please ignore my comment, though I will leave it to make the below comments less confusing.

Original: You don't want to "work out" your heart though. Cardiac hypertrophy is a bad thing.

The benefit of exercise is that your muscles become more oxygen-efficient. Your heart endures some stress now, so that it can work less in the future.

[kiritanpo]

Cardiac hypertrophy is not necessarily a bad thing, it can be the result of positive adaptation, such as exercising.

Eccentric hypertrophy (athlete's heart) is the positive adaptation resulting from training the heart. The heart has a lower resting rate and is more efficient at pumping blood. It returns to normal size if training stops.

You'll never reach a state of hypertrophic cardiomyopathy (the bad kind of hypertrophy) with exercise. Its cause is usually genetic.

[kazga]

Not true. You can't really train your muscles to use less oxygen for the same energy output (what "oxygen-efficiency" would imply). You rather increase their capacity to take up oxygen from the blood and burn it. They will use more oxygen to output more energy.

That additional oxygen needs to come from somewhere. Endurance training at the same time trains the heart to deliver more oxygen to the periphery; the primary mechanism is increased cardiac stroke volume.

[bluGill]

You kind of can - the muscles can use aerobic or anaerobic processes. When you develop brute strength you are training those anaerobic processes. That isn't what OP was talking about, and overall it is much less energy efficient, but it does produce a large burst of energy when needed and you can train your muscles that way.

[gf000]

I would assume that another factor is that the technique for a given exercise on the other hand can be improved, and that can help with decreasing the necessary energy - would that be a correct statement? And as a follow up, depending on activity type this may or may not be significant?

[frocodillo]

Yes, definitely. Technique is partly about efficient mechanical movement, sending the various parts of your body in the right direction(s) and not waste effort on movement that doesn’t contribute to propelling you forwards. But for endurance sports, it’s really about minimizing energy cost at a given speed. To use running as an example, you can improve biomechanical efficiency through better timing, correct loading of tendons, tendon stiffness, elastic energy use, and more.

[SJMG]

This is terribly uniformed. Do not listen to this.

Cardiac hypertrophy isn't a "bad thing". This is completely contextual. What you don't want, for example, is pathological hypertrophy from things like hypertension, or exclusive left ventricular hypertrophy without associated increase in chamber size.

The heart is very complex. You 100% should exercise it.

[adrianN]

Wikipedia says Athlete's heart is benign: https://en.wikipedia.org/wiki/Athletic_heart_syndrome

[groundzeros2015]

This is why I hate health science. Informed people can have the same information and come to opposite conclusions. The entire field is made up of contradictory explanations and principles, to the extent that it’s unknowable what’s true or not.

[robrenaud]

The flat earthers are why I hate astronomy.

Afaict, the grand parent poster is just very wrong. You do want to cause acute stresses to your heart (cardiovascular exercise) to get it work better.

[groundzeros2015]

It’s not really about this particular claim. It’s that I can read a comment that has a reasonable chain of logic and I don’t know if it’s true. This topic is just not easily studied and theories are hard to falsify.

[groundzeros2015]

Claims about flat earth are falsifiable with at-home experiment.

[rhyperior]

That seems… misguided.

Sources?

[jagged-chisel]

Your heart is also a muscle.

[PaulDavisThe1st]

... about the size of your fist. Keep loving, keep fighting.

(attributed to Bertolt Brecht)

[bluecalm]

For endurance training the main benefit of heat training is raising blood volume. Lungs are not a limiter. Developing stroke volume I imagine requires much higher intensity but that's just a wild guess based on my limited understanding of physiology.

If heat training is better than another interval session remains to be seen but it seems a lot of smart people believe it's worth it nowadays.

[PaulDavisThe1st]

and specifically, to be clear, plasma volume.