Heart Rate Range & Target Heart Rate

[Gammmmo]

Maybe it wasn't THAT stressful...surely you've had acutely stressful situations where you FEEL you HR going up? An extreme verison of this (and admittedly this may be down to adrenaline) would be easy to envisage e.g. that sudden noise in the night where you wake up instantly and are super alert because you perceive possible danger....result: HR nearly beating out of your chest while u lie in bed!!

You shouldn't mix up HR and HRV. The case you describe strongly affects HR. What is does to HRV is anybody's guess. The Polar fitness test measures HRV in rest. See https://en.wikipedia.org/wiki/Heart_rate_variability .

Regarding the question whether the relation between fitness and resting-HR is weak or strong, it may help to explain these terms. If a (cor)relation is strong, knowing one quantity almost fixes the other. In a large group of healthy people you can find several with a resting-HR of 55 bpm. However, they are most likely not equally fit. So for groups the relation is bound to be weak. Also taking myself: this morning my resting-HR was about 50. In the early afternoon it may easily drop to 45, occasionally 43. I assume that my fitness does not change over the day. So also for individuals the relation between fitness and resting-HR is weak.
Polar claims that their fitness test based on HRV produces a stable score and I have found little experimental evidence that this is not true.

So the 41,42, 40 is more to do with HRV?

re: HR varying throughout the day due to fitness..splitting hairs. You could argue that HR is affected not just by fitness but other stuff too such as hydration level, circadium rhythm (there is a tendency for people to perform best at sports later in the day), body temperature etc and therefore there is small short term variation in fitness, but again it's splitting hairs.

[Mortie31]

I track HRV as well, but not sure about the strong link with fitness, how much is good? Mine varies widely over a 24 hour period, even a restless nights sleep dramatically reduces the daily average, could you link any papers you have read, as their are multiple factors that affect HRV, stress being one of them, HRV is a good measure of the balance of the autonomic response.

On the internet you can find many scientific papers on Heart Rate Variability in relation to athlete performance. Some of them are very technical about how to measure HRV. Here is one that concentrates on monitoring physical performance : https://www.researchgate.net/publicatio ... Activities . I could download it free of charge.

Fitness is a common word used in many ways. It can be used to characterize a person's physical performance level with respect to the general population. It can also be used to describe one's day-to-day fluctuations in performance. The aim of the Polar fitness test is clearly to rank a person's physical ability compared to a general group of the same age: https://support.polar.com/en/support/ho ... tness_test . Over the last two months I did this test 10 times. The average was 41.7 and the standard deviation 0.5. In my age group (>70 yrs), a result >40 is excellent ; the age group's average is 29-32. So the test is clearly able to discriminate within a large group of people. I don't think the test can track day-to-day fluctuations.

Yes, metal stress is known to affect the result of the fitness test, but as far as I was able to find out not in a big way. This morning I measured my fitness lying down on a bed face-up before breakfast and morning exercise : result 41. After a 5K row (final 1K at 92% of HRmax) and a shower, I repeated the fitness test sitting upright facing an empty computer screen : result 42. The next measurement was done a few minutes later while participating in a sudoku competition on the internet. This is usually my most stressfull activity of the day because the score is based on the time needed to solve the puzzle: result 40. Take this as anecdotal evidence that stress is a minor effect.

Interesting results, I track my HRV on an iwatch4 as well as my polar h10, I get HRV readings anywhere from 15 to 180m/s, I generally get about 7-8 readings a day. You can trigger an HRV reading on a iwatch by using the breathe app, so their not using it as a measure of fitness but one of stress. The available literature is sketchy to say the least, but as a measure of stress, in particular the body’s fight or flight response is interesting, I think polar are being abit disingenuous in using HRV as a fitness measure, as a marketing tool as the science is still emerging and nothing conclusive so far..

[Nomath]

So the 41,42, 40 is more to do with HRV?

re: HR varying throughout the day due to fitness..splitting hairs. You could argue that HR is affected not just by fitness but other stuff too such as hydration level, circadium rhythm (there is a tendency for people to perform best at sports later in the day), body temperature etc and therefore there is small short term variation in fitness, but again it's splitting hairs.

Yes, 41, 42, 40 are the scores of the Polar fitness test when I tried to measure the mental stress effect. Repeating the test, in the way Polar recommends, 10 times over a period of 2 months resulted in an average of 41.7 and a standard deviation of 0.5. Hence the score, which estimates VO2max, is very reproducible. Isn't it remarkable that one can estimate one's VO2max accurately by just lying down and breathing minimally?

Your above summing up provides many reasons why rest-HR has a weak relation to fitness.

[Gammmmo]

Your above summing up provides many reasons why rest-HR has a weak relation to fitness.

But this is my point about splitting hairs....yes, you can get some sort of variation (due to the factors outlined) in RHR for an individual and "fitness" may change to a small degree in a commensurate way. That doesn't change underlying well-rested fitness though. So you may then draw a (IMO false) conclusion that RHR correlates weakly with fitness but generally when we talk about RHR and fitness for an individual we think of that for someone well rested and we compare-like-with-like with another individual. I've already said TDF pros would have RHRs in the 30s mainly and some into the 40s (whether you consider that span as fuel for your idea of correlating weakly is up to you) but if RHR was weakly correlated with fitness why don't we see pros with RHRs in the 50s,60s, 70s en masse as per some sort of random distribution? You don't.

[hjs]

Your above summing up provides many reasons why rest-HR has a weak relation to fitness.

But this is my point about splitting hairs....yes, you can get some sort of variation (due to the factors outlined) in RHR for an individual and "fitness" may change to a small degree in a commensurate way. That doesn't change underlying well-rested fitness though. So you may then draw a (IMO false) conclusion that RHR correlates weakly with fitness but generally when we talk about RHR and fitness for an individual we think of that for someone well rested and we compare-like-with-like with another individual. I've already said TDF pros would have RHRs in the 30s mainly and some into the 40s (whether you consider that span as fuel for your idea of correlating weakly is up to you) but if RHR was weakly correlated with fitness why don't we see pros with RHRs in the 50s,60s, 70s en masse as per some sort of random distribution? You don't.

Guys, maybe make poll and ask about rest hf, 2k time, age/height/weight, maybe it brings something.