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Sauna effect on heart rate

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Re: Sauna effect on heart rate

#131

Post by p1anecrazy »

storus wrote: post #97

Can anyone suggest why after covid I can't do Finnish sauna anymore? Prior to that I used to do 1-2x a week a sequence of 5x(10 minutes in sauna + 5 minutes cold water immersion + 10 minutes rest) which was absolutely great for both stress reduction and blood flow. Now if I do 5 minutes in sauna I feel like my skin was burning and I am about to die, and I need to recover for 1 hour from that to be able to just walk a…

Once in a while as I get sick I have to retrain myself to going to sauna (e.g. taking lowest level, even skipping the Aufguss, German infusion where temperature is raised gradually etc.)

Also IMO your body fat/water/lean muscle ratio may play a role. I once lost 5 kg due to Influenza A and all my sport achievements as well as sauna endurance were gone

Re: Sauna effect on heart rate

#132

Post by pegasus »

bluGill wrote: post #6
kyriakosel wrote: post #2

Author here. Methodology upfront because I'd ask the same things: Data: daily records from wearable users who logged sauna sessions via connected apps. Within-person design — each user is their own control, comparing their own sauna-day nights against their own non-sauna-day nights. No cross-user comparisons. Stats: paired t-tests, FDR-corrected p 0.2 threshold for "meaningful effect." Anything below d=0.2 we don't r…

The most important thing you didn't measure: does this affect long term health in the same way exercise it known to. That is can I put a TV in my sauna and watch that for an hour every day instead of getting out and exercising - yet get the same better long term health outcomes? My current guess is no. That is this improves a marker for good health without improving health. However this is a guess by someone who isn'…

Since you mention the TV, it seems there's a big factor missing in both the article and the discussion here. Namely, that sauna time is for many people the only time they ever take to be in silence, without the countless distractions otherwise bombarding our nervous systems. I.e. it's basically a form of informal meditation, which is known to have a lot of benefic impacts on body and mind. So maybe skip the TV part?...

Re: Sauna effect on heart rate

#133

Post by jampekka »

gjulianm wrote: post #126
jampekka wrote: post #116

Earlier quoted context omitted.

I don't understand what you mean by that. Precision (inverse of variance) of estimate of mean increases directly proportional to number of samples (given some assumptions that very likely hold here). If you have measurement standard deviation of say 10 bpm, with 100 measurements you have mean estimate standard deviation of 10/sqrt(100) = 1 bpm.

> of estimate of mean But you can't really assume that the estimate of the mean represents the real value. For example, if the sensor is equally likely to show 80 or 81 BPM when the real heartrate is 80.7, the mean estimator will be biased. > with 100 measurements Also, wearables aren't taking 100 measurements of the BPM at a given point in time. I think the highest frequency they usually have is 1 second measurement…

> But you can't really assume that the estimate of the mean represents the real value. For example, if the sensor is equally likely to show 80 or 81 BPM when the real heartrate is 80.7, the mean estimator will be biased.

Bias is different from precision. If both conditions have the same bias, their difference is still unbiased.

> Also, wearables aren't taking 100 measurements of the BPM at a given point in time. I think the highest frequency they usually have is 1 second measurement interval. So they don't really have a lot of measurements for each point in time.

I did not mean taking multiple measurements in succession. Those are likely to have correlated noise, meaning the assumptions do not hold. But between participants measurement noise is very unlikely to be correlated.

> That as a rule of thumb, you should not assume that repeating measurements will give you more precision than what the tool can offer. E.g., trying to measure down to milimeters with a ruler that has only 1cm marks will not really work well.

If you quantize so much that you have no variance in the measurements, then sure. But watches typically have 1 bpm quantization, which is fine at the scale of variation in HR.

If you have independent error in measurements and quantization that gives you variance in measurement, you very much can assume repeating measurements will give you more precision than the tool can offer. This is how e.g. particle physics (and many many other fields of science) is done.

Re: Sauna effect on heart rate

#134

Post by p1anecrazy »

kyriakosel wrote: post #2

Author here. Methodology upfront because I'd ask the same things: Data: daily records from wearable users who logged sauna sessions via connected apps. Within-person design — each user is their own control, comparing their own sauna-day nights against their own non-sauna-day nights. No cross-user comparisons. Stats: paired t-tests, FDR-corrected p 0.2 threshold for "meaningful effect." Anything below d=0.2 we don't r…

Appreciate it as a regular sauna-goer. I am also struggling to wake up after sauna evenings and maybe you research explains why

Re: Sauna effect on heart rate

#135

Post by yxhuvud »

jeffbee wrote: post #91
somebodythere wrote: post #59

Earlier quoted context omitted.

There is some evidence suggesting that "blue zones" are largely about pension fraud. https://fortune.com/europe/2024/12/14/are-blue-zones-myth-ex...

You're saying that crime leads to longevity? Big if true.

No, he is saying bad record keeping means misreporting identity has a bigger chance of happening.

Re: Sauna effect on heart rate

#137

Post by jampekka »

storus wrote: post #125
mcv wrote: post #119

Earlier quoted context omitted.

95 is pretty hot. At commercial spas I see them start at 70, and rarely above 90.

95 is normal where I live for Finnish saunas. Then there are other types of saunas that start lower, but Finnish are always around 95.

95 is high for Finnish saunas in Finland at least. Public saunas are very rarely so hot here, and few like it that hot.

Edit: to put it into some numbers, per one study[1] Finnish sauna sessions were on average at 75.9°C with SD 9.9°C. If we assume normal distribution, that means that more than 97 % of sauna sessions are at [1] https://pmc.ncbi.nlm.nih.gov/articles/PMC6262976/

Re: Sauna effect on heart rate

#139

Post by MyHonestOpinon »

I try to do 180 minutes a week of cardio. Mostly Zone 2. Biking, elliptical, tKD. But once in a while my legs feel too tired, so I complete my weekly minutes going to the steam room. It makes sense to me since it raises your heart rate.

Also, my samsung watch can measure stress (whatever it means). It always shows the very, very minimal stress for me. The only time that I have been stressed was the day that I spent a bit too much on the steam room.

Re: Sauna effect on heart rate

#140

Post by bluecalm »

nsbk wrote: post #21
bluGill wrote: post #6

Earlier quoted context omitted.

The most important thing you didn't measure: does this affect long term health in the same way exercise it known to. That is can I put a TV in my sauna and watch that for an hour every day instead of getting out and exercising - yet get the same better long term health outcomes? My current guess is no. That is this improves a marker for good health without improving health. However this is a guess by someone who isn'…

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…

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.

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