Heart-Rate Recovery as a fitness indicator?

[Carl Watts]

It's a useful metric but not to compare yourself to others just to yourself. Obviously as your fitness improves your HR decay curve is steeper and drops closer to your resting HR faster. I used to find 2 minutes was better it allowed the HR to plateau and show a decent fall.

[contradictus]

Hey guys,

sorry to jump in, but I am confused with the idea that a quick heart rate rise should be a good indicator. I always thought to opposite is the case, given a permanent load.


Can someone please set it straight bit?

[hjs]

Hey guys,

sorry to jump in, but I am confused with the idea that a quick heart rate rise should be a good indicator. I always thought to opposite is the case, given a permanent load.


Can someone please set it straight bit?

Not a quick raise itself, but when needed. If you do a max effort having a body that rapidly fires at all cylinders is sign of good health and fitness. Just like dropping is when you stop that effort.

[contradictus]

Thx man!

[Nomath]

sorry to jump in, but I am confused with the idea that a quick heart rate rise should be a good indicator. I always thought to opposite is the case, given a permanent load.

Can someone please set it straight bit?

Your apparently simple question is surprisingly hard to answer, evidence-based. I am amazed that hjs who admits not having used any HR monitor in years has given an answer. An intuition-based guess?

I did a quick literature search with Google, but it is hard to find studies about heart rate dynamics. Most studies are about stationary effects. For example, you find that after a period of intense training the rise in heart rate under a certain load is less than before the training. So there is evidence of fitness on the rise in heart rate, but not that the rise happens more quickly.

The point is that that the heart rate of an athlete not only reflects the external load, but also internal factors like fatigue, hydration, mental stress, etc. in additition to external factors like temperature and humidity. So you see that the HR response to a defined variable load is a rather blurred replication of that load. The dynamic parameters are even more difficult to discern than the plateau parameters (picture from Hunt, Identification of heart-rate dynamics during cycle ergometer and treadmill exercise).



One basic fact that escapes most people who use a common heart-rate monitor is that the heart rate, even in complete rest, is not a very stable value, say stable within ±1 bpm. The figure below shows a typical electro-cardiogram of a person in rest over a span of about 10 sec (taken from a paper by Achten and Jeukendrup). The intervals between the R-pulses vary between 883 ms (68 bpm) and 979 ms (61 bpm). Common heart rate displays, whether Polar, Garmin or no-name, will always take an average over several seconds, because no user likes a quickly fluctuating number on display.



What you see in the graph is called heart rate variability (HRV). It's a feature that has been investigated in medical studies because it appears to be a prime indicator of the cardiac health of an individual. The heart is not a metronome beating at fixed intervals, but an organ that responds autonomeously to slight internal and external disturbances. Even without external disturbances, there is heart rate variability. It has been found that HRV in rest is a very good measure of the cardiac fitness of a person: higher HRV > higher fitness. There is even a strong relation between HRV and VO2-max, the maximum oxygen uptake. I find this astonishing, as the HRV is measured lying on a bed and the VO2-max is determined at maximum physical effort. Some Polar devices use HRV to estimate VO2-max.

My expectation is that a high HRV, hence a high cardiac fitness, implies that the heart reacts fast to any change in external load. So the fitter the athlete, the quicker the heart rate rises with a change in load. You may call this an educated guess.

[hjs]

sorry to jump in, but I am confused with the idea that a quick heart rate rise should be a good indicator. I always thought to opposite is the case, given a permanent load.

Can someone please set it straight bit?

Your apparently simple question is surprisingly hard to answer, evidence-based. I am amazed that hjs who admits not having used any HR monitor in years has given an answer. An intuition-based guess?

Using or not, one persons numbers mean nothing for the whole population.
Re raising, hf, you get that by going very hard, not the way hf devices are used.

Although there are certainly benefict for some to use hf devices. But it does have minuses, you should be able to feel what you body is telling you. If you can’t feel you are tired or fresh, thats the problem.

Most people have obvious points to improve, hf numbers will not help. Using hf devices during races or tests often work agains you. Instead of having the focus on the actual work and feel, people start looking at their hf. Not seldom leading to wrong decisions. Handling down, slowing down etc.
Our heart has a big reserve, seeing a high hf in itself is nothing to be scared of. That is if you are feeling fine.

In short, using hf devices can have it merits, but look at it in the bigger picture. Its one variable, not the only one.


Two personal examples from me. Once did a 30 min race. Wearing a hf device. From around 20 min in, my hf reached my max. 191 at the time. It more or less flatlined from there to the finish. No ill effects etc.

Second example. Before a race I used to do a 1500 test, caping it at 93% of my hrr. Once did that test in very cold conditions. Had a very difficult time reaching my cap. Which made me dig in deeper than I should and wanted to do.

[contradictus]

@ Nomath: I like your "educated guess"! Thx for your research work done (as I am not an english-native and lacking the technichal language even in my own tongue I do not like to go on this road ... which I should one day).

@ hjs: agreed. As my "problem" is to tend to overtraining or rather pushing too much into one session, the HR-monitor is great for the disciplin, though.

[flatbread]

Two personal examples from me. Once did a 30 min race. Wearing a hf device. From around 20 min in, my hf reached my max. 191 at the time. It more or less flatlined from there to the finish. No ill effects etc.

Second example. Before a race I used to do a 1500 test, caping it at 93% of my hrr. Once did that test in very cold conditions. Had a very difficult time reaching my cap. Which made me dig in deeper than I should and wanted to do.

and this is why it's best to use HR monitors, cycle powermeters, or the PM5 descriptively rather than prescriptively

[hjs]

@ Nomath: I like your "educated guess"! Thx for your research work done (as I am not an english-native and lacking the technichal language even in my own tongue I do not like to go on this road ... which I should one day).

@ hjs: agreed. As my "problem" is to tend to overtraining or rather pushing too much into one session, the HR-monitor is great for the disciplin, though.

Yes, to stop racing in training, hf capping can be very usefull.

[Nomath]

I started this topic with a question mark. So it seems appropriate to add my own observations on heart rate recovery over the last two months (Aug-Sept).
My usual daily exercise is a 5K row without pause. I have done 35 of them over these months. I follow no training schedule and usually decide on the spot whether I will go easy or hard, often depending on the feeling in the first 1K. Always my effort and heart rate increases towards the end. My heart rate is monitored and logged by a Polar M460.

A typical graph of the HR during and after a 5K is shown below. The record starts with a rest of 1 min. My resting HR is 50-60 bpm. My HRmax is about 160 bpm (72 yrs), so my personal HR range amounts to about 100 bpm.
After the start (dashed vertical line 1), the HR does not change for about 10 sec and then starts to rise. After finishing 5K (vertical line 2), I stop completely. In heart rate recovery studies this is called a passive rest (in contrast to an active rest when you reduce the effort to a very low level). After the stop, the HR doesn't change for about 10 sec and then starts to drop. The M460 data-log allows to read the HR precisely at 60, 120, 180 sec after the stop (lines 3,4,5,etc..).



The graph below shows the measured heart rate recovery after 60 sec of these 35 runs as a function of the heart rate at the 5K finish. As said before, these numbers are highly individual, but I believe that the trends will apply to all rowers and probably to all endurance athletes.
The graph shows that with a HR-finish below 150 bpm (=94% of my HRmax) the HRR is roughly independent of the effort. In my case : 50-60 bpm. Above 94% the HRR tends to decrease sharply. I have found no clue why after a very hard exercise there is a lot of variability in HRR.



Anyway, in the sport science articles I did not find a study of HRR versus intensity, so this result may be novel, although not surprising. HRR is probably more an intensity indicator than a fitness indicator.

[jamesg]

60 seconds is a long time for the heart. Instantaneous drop rate/range could be better, since drop appears to be roughly asymptopic, and could give a number rendering the measurement independent of effort level.

[Nomath]

Drop in heart rate 60 seconds after ceasing exercise is the most used metric in sport science. Several studies have been done whether 120 or 180 sec Is preferable, but this appears not the case, probably because a shoulder peak often occurs after 60 sec (see my track above).

Instantaneous drop after ceasing exercise is meaningless. I observed that in the first 10 seconds (roughly) after ceasing exercise the heart rate does not drop but stays level to the rate at the finish. The same time lag also occurs after start of exercise. I don’t know whether this 10 sec time lag is the same for each person, but I am sure that HR always lags activity by more than a handful of seconds.

[jamesg]

One minute drop in heart rate was used on us in the 1950s. It required a standardised effort (a step test for a certain time at a certain rate).

Today more sophisticated methods are available, as your graphs show.

The drop curve can probably be considered approximately half a hyperbola, y = k/x. Bumpy curves are routinely modeled, and it should not be impossible to extract a value for k. If this is the data available today, why not use it.

[Nomath]

One minute drop in heart rate was used on us in the 1950s. It required a standardised effort (a step test for a certain time at a certain rate).
Today more sophisticated methods are available, as your graphs show.

A lot has changed since the 1950s, but not 60 sec as the standard time for measuring recovery.

My own recollection doesn't go as far back as yours, but in the mid-70s measuring heart rates during activity did require special equipment. I remember running on a treatmill with several wired electrodes pasted on my naked chest. A 3-way mouthpiece funneled the exhaust gas into a Douglas bag. In my country (NL) only a few specialized labs could do this. At home I had to sense the heart rate with a finger on the wrist and count the beats in 20 sec, then multiply by 3. Not very accurate and hardly suitable when the heart rate was rapidly changing. Only when Polar introduced its ECG breast sensor, in 1983, could we conveniently measure instantaneous heart rates. Also the tools for a controlled work effort have improved a lot. Instead of a step test we now have a cycle erg or a rowing erg.

As recently as 2018, a paper was published in the International Journal of Performance Analysis in Sport about the use of heart rate diagnostics in professional football (soccer). It was a survey of 137 clubs playing in the top European divisions (France, Spain, Italy, Germany, UK) and Champions League clubs from other countries. You may expect professional coaches in performance fysiology working with these clubs, using the most advance tools. The survey had the aim of identifying the procedures used for measuring Heart-Rate Recovery and Heart-Rate-Variability. Within respondents, 50% used HRR and 36% HRV. The majority of the clubs reported the use of raw HR 1 min after the end of the exercise in standing position to measure HRR.
See https://www.tandfonline.com/doi/abs/10. ... 18.1460053

Also in medical diagnostics, recovery in 60 sec after a maximal or submaximal exercise is the standard.

Curve fitting may seem more sophisticated, but it has no scientific background. Most recovery curves that I observed didn't look hyperbolic. Measuring the drop in 60 sec is a lot more practical.

[jamesg]

Agreement seems somewhat limited:

Within respondents, 50% used HRR and 36% HRV; the 47% that do not use HRR deemed it to be of no interest and the 54% that do not use HRV deemed it too restrictive.

I tried measuring my own drop this a.m, doing 5x5' + 90s rest, noting HR at 10 and 70s after stopping. It was the first time I ever did that, and there was some confusion due to the ergdata "have u had enough" screen popping up in front of the numbers and HR jumping around too. Anyway, I think I saw roughly 25/min drop on average, starting from average 130 max. My rest rate is about 60, and 25/(130-60) = 36%, which seems to be enough to keep me alive.