Looking for fitness information

[frankencrank]

I am looking to write an app that takes readily available fitness information and then determine relative heart attack risk. The advantage of this to the user would be several helping to answer these questions.

1. Should I buy more insurance.
2. Should I see a doctor?
3. Should I change my exercise program?

The whole idea depends upon my being able to predict your exercise stress test tolerance. What got me to think about this is the Apple Watch grossly underestimates my exercise capacity. I am 78 and it tells me my fitness is below average with a VO2max of about 24 when recently I had a stress test and got over 13 mets which is equivalent to a VO2max of about 50. This difference really bothered me and, even though I don't have any idea how apple comes up with its numbers I wondered if I could come up with something better.

My method looks only at resting HR and sustainable HR (just below anaerobic threshold) and uses physiological principles to predict max mets in an EST. This data is then compared to a paper that analyzes risk vs age vs mets capacity.
https://www.ahajournals.org/doi/epub/10 ... 114.009666

For myself, my method predicts my EST performance to be about 12 when I actually performed about 13. Pretty close. That puts me in the high fitness group according to the above paper.

What I would like would be to get some data from those of you who have had recent stress test so I can validate that my method works for others also. All I need is your resting HR (Apple Watch gives that to you but it is simply your HR when fully rested and quiet) and your highest aerobic HR (a HR you can exercise at for 10 minutes or so without it creeping up or seeing increasing fatigue). I might add that I am on a beta blocker. I think the method will work whether one is on such drugs or not.

You can PM me if you don't want such data public.

Thanks for your help.

[Ombrax]

Is there such a thing as a forum where cardiologists hang out?

If so, it seems to me that that would be a good place to ask this sort of question. But they'd probably not say anything due to liability concerns. (which of course would be an issue for any app that provides the type of information mentioned above)

[frankencrank]

Is there such a thing as a forum where cardiologists hang out?

If so, it seems to me that that would be a good place to ask this sort of question. But they'd probably not say anything due to liability concerns. (which of course would be an issue for any app that provides the type of information mentioned above)

Cardiologists don't have the information I want or need. For them to gather this they need to do institutional review, etc. and they really don't care. They run their Stress tests but they don't really know the resting HR of those patients nor how they exercise in the field. I am looking for field information to correlate with Stress test results. Those that hang out here should be able to help.

The other problem with cardiologists is they are dealing with "abnormal" hearts. I am looking to see about the "normal" asymptomatic person who exercises. Seems I might find a few here.

Give me your data and see if I can predict your Stress test results (if you have one). No liability involved.

[Ombrax]

The other problem with cardiologists is they are dealing with "abnormal" hearts.

I know essentially nothing about the topic and will gladly defer to you, but I would think that those who do research in that area would have to gather data from all types of people, both those with "good" and those with "bad" CV systems, otherwise they wouldn't be able to define what's healthy and what isn't when someone shows up with issues that may or may not be related heart or circulatory problems.

Happily for me, I've never had the need for a stress test (other than rowing or riding the bike hard) so I don't have anything to help you.

[JaapvanE]

What got me to think about this is the Apple Watch grossly underestimates my exercise capacity. I am 78 and it tells me my fitness is below average with a VO2max of about 24 when recently I had a stress test and got over 13 mets which is equivalent to a VO2max of about 50. This difference really bothered me and, even though I don't have any idea how apple comes up with its numbers I wondered if I could come up with something better.

This probably is the FirstBeat algorithm, that powers most smartwatches, including Garmin. There are quite some scientific studies behind its algorithm. What it does, is measure the HR and its variability during an excercise and extrapolate that to maximum HR to get to get maximum delivered effort (typically power) and calculate VO2Max based on that. (see https://sportcoaching.co.nz/how-does-ga ... e-vo2-max/ and https://sites.udel.edu/coe-engex/2019/0 ... -estimate/). Concept2 also has a formula based on decent studies, see here:
https://www.concept2.com/indoor-rowers/ ... calculator

At age 78, you are probably a huge outlier. In all honesty, a VO2Max of 50 is almost unheard of in people over 60.

These metrics are nice are systematic enough to provide athetes feedback on their progress, but they are not a good indication of the absolute value to tell them where they stand with respect to the field. Even with Firstbeat, they are off for most athletes. (Lack of) techique, but also unmeasured elements come into play.

And to be honest, the stress test is a nightmare. It typically takes a subject a week or two to recover.

My method looks only at resting HR and sustainable HR (just below anaerobic threshold) and uses physiological principles to predict max mets in an EST. This data is then compared to a paper that analyzes risk vs age vs mets capacity.
https://www.ahajournals.org/doi/epub/10 ... 114.009666

For myself, my method predicts my EST performance to be about 12 when I actually performed about 13. Pretty close. That puts me in the high fitness group according to the above paper.

Interesting, but that still subject to what in fact is the biggest issue with FirstBeats algorithm: most people just gamble their max HR....

[Ombrax]

And to be honest, the stress test is a nightmare. It typically takes a subject a week or two to recover.

Not to drift too far from the OP's question, but I've always wondered, how hard does one typically go in a medical stress test (as opposed to a VO2 max test, which I assume means max, since it's called max).

The quick look I just did via Google said that they often go to 85% of max predicted HR, and that they get predicted using 220 - age (which as we know is not that accurate).

I ask because for most of us I'd think that when we're healthy a test at 85% of 220-age would likely be a walk in the park.

[JaapvanE]

Not to drift too far from the OP's question, but I've always wondered, how hard does one typically go in a medical stress test (as opposed to a VO2 max test, which I assume means max, since it's called max).

The quick look I just did via Google said that they often go to 85% of max predicted HR, and that they get predicted using 220 - age (which as we know is not that accurate).

There is more than one test, and there is quite a lot of literature that suggests that there even isn't a single VO2Max: for example I'm much better at cycling than running, so my VO2Max would differ between the two types of excercise.

Looking at the test, nowadays they typically do a step test: start at low power and increase it every x minutes until some max is reached. Ideally you want to measure the level of O2 taken in at the moment the body switches from aerobic to anearobic energy.

Sometimes they measure lactate production (the typical indication that the anearobic energy production kicks in and the earobic system has collapsed, probably due to O2 shortage). However, lactate measurement is invasive (blood), so difficult to measure in-situ. So they like to use 85% of Max HR as that is the lactate threshold for most people (but that is on average, athletes typically have different thresholds due to their training).

In these tests, the problem keeps measuring the real Max-HR. That involves maxing out the subject to a real Max HR, often leading to collapse for untrained people. Please note, while rowing we can reach a HR peak, but are typically sane enough not to push it too far. During the test, you are pushed to that limit. That is part of the real stress tests, and that is the one that sucks big time. It has adverse effects on the body, as explained here for runners: https://www.youtube.com/watch?v=Y6U728AZnV0. Reaching such high HR damages the heart muscle, which will recover but you really need to recover after such a test. For me, it really was only conducted after the end of the season and downtime was planned for it (typically two weeks without any cardio training). As the video explains, tipping that high HR's isn't that smart, especially when done frequently.

I was a trained athlete back then, they did the test once every two years (that in itself is an indication as most metrics are measured at least once per year) and were conducted at a university hospital under close supervision. They tested both lactate production (so blood and needles stuff) and maxed us out anyway to find max HR as much training is based on it. Being trained we didn't collapse but you are going to meet the man with the hammer, and he has brought along all his friends for the party. According to a friend triathlete: the after-effects are like having ran a marathon (which always sounded like a warm-up lap coming from him). It takes a while for all muscles have recovered from the high lactate levels.

Looking from web resources (see https://www.hopkinsmedicine.org/heart_v ... sting.html) the key test seems the same. I can imagine they skip the lactate tests for normal people.

I ask because for most of us I'd think that when we're healthy a test at 85% of 220-age would likely be a walk in the park.

It should be, as the 220-age is conservative, and even 85% at a real observed HR is usually doable. The problem is that for the real test, you want to be closer to 99% of MaxHR. For example, my highest observed HR in the last two years was 186 (which is pretty decent for a overweigt 50-year old , and well above the predicted 170). When I just row without watching my HR, I easily reach 158 around 4-5K, but I can easily walk away. When I touch the 170, still no issues. When I row a 6K at race pace, I'll touch the 180 at the end for a minute or two. Takes me a couple of minutes to recover, and probably half a day to be physically fit again. When I touch 186, I need to be taken outside afterwards to catch my breath, and it takes me two nights to physically recover completely. Getting closer to that real HR limit is increasingly costly.

[Ombrax]

@JaapvanE

Thanks for the detailed response - that's useful information.

[Carl Watts]

Suggested C2 put a fitness level test in the PM5 years ago never happened. They have a load of data through the online logbook would be really useful. The only thing you can do is rank a row and see where you sit in the field of others in your age group. Probably not a bad indication to be honest just look at the percentile you can hit.

[JaapvanE]

Even that is only a correlation at best. The factor rowing technique/effectiveness is between the effort put in and what the C2 actually measures. And HR is an interesting metric, if only you knew what the max HR actually was (und thus how hard the relative effort was for that person). These are the fundamental issues underlying all these fitness tests: you are working on derived metrics only, most based on sloppy correlations at best. Not the stuff you wan't to advise on their heartattack risk....

[frankencrank]

The other problem with cardiologists is they are dealing with "abnormal" hearts.

I know essentially nothing about the topic and will gladly defer to you, but I would think that those who do research in that area would have to gather data from all types of people, both those with "good" and those with "bad" CV systems, otherwise they wouldn't be able to define what's healthy and what isn't when someone shows up with issues that may or may not be related heart or circulatory problems.

Happily for me, I've never had the need for a stress test (other than rowing or riding the bike hard) so I don't have anything to help you.

If you noticed I posted a link to a study where such correlation was done. I am simply trying to apply physiological principles to allow ordinary people to use data available to them to get an estimate of their relative risk as determined by that study.

What I would like to know is whether ordinary people (like you) can discern that data such that my algorithm comes close to predicting their actual results.

[frankencrank]

What got me to think about this is the Apple Watch grossly underestimates my exercise capacity. I am 78 and it tells me my fitness is below average with a VO2max of about 24 when recently I had a stress test and got over 13 mets which is equivalent to a VO2max of about 50. This difference really bothered me and, even though I don't have any idea how apple comes up with its numbers I wondered if I could come up with something better.

This probably is the FirstBeat algorithm, that powers most smartwatches, including Garmin. There are quite some scientific studies behind its algorithm. What it does, is measure the HR and its variability during an excercise and extrapolate that to maximum HR to get to get maximum delivered effort (typically power) and calculate VO2Max based on that. (see https://sportcoaching.co.nz/how-does-ga ... e-vo2-max/ and https://sites.udel.edu/coe-engex/2019/0 ... -estimate/). Concept2 also has a formula based on decent studies, see here:
https://www.concept2.com/indoor-rowers/ ... calculator

At age 78, you are probably a huge outlier. In all honesty, a VO2Max of 50 is almost unheard of in people over 60.

I am definitely an outlier (although I can assure you there are others out there "better" than I). When I had my stents placed I had to go to cardiac rehab. The nurses there were so freaked out by the HR's I was at they forced the doctor to stop the rehab until I had a stress test. That is where I measured over 13 mets. What bothered me about this was these nurses were so inexperienced or poorly trained that they could not do a clinical evaluation but took a one size fits all approach. Someone who is at the supposed max HR but talking to them comfortably is not going too hard! It sure wasn't how I was trained.

These metrics are nice are systematic enough to provide athetes feedback on their progress, but they are not a good indication of the absolute value to tell them where they stand with respect to the field. Even with Firstbeat, they are off for most athletes. (Lack of) techique, but also unmeasured elements come into play.

And to be honest, the stress test is a nightmare. It typically takes a subject a week or two to recover.

Wouldn't it be nice if there was a way to predict stress test results without the need for a full stress test? Of course, one of the reasons for a stress test is not necessarily to see what the ultimate number is but, rather, to see if there is any cardiac dysfunction at the limit so they are still going to be done but, perhaps, only in those who are symptomatic.

My method looks only at resting HR and sustainable HR (just below anaerobic threshold) and uses physiological principles to predict max mets in an EST. This data is then compared to a paper that analyzes risk vs age vs mets capacity.
https://www.ahajournals.org/doi/epub/10 ... 114.009666

For myself, my method predicts my EST performance to be about 12 when I actually performed about 13. Pretty close. That puts me in the high fitness group according to the above paper.

Interesting, but that still subject to what in fact is the biggest issue with FirstBeats algorithm: most people just gamble their max HR....

As far as I am concerned no one need ever push themselves to their max HR. Anaerobic exercise should be reserved for escaping lions (or winning gold medals). True cardiac fitness for most people comes from sustained aerobic efforts.

[frankencrank]

And to be honest, the stress test is a nightmare. It typically takes a subject a week or two to recover.

Not to drift too far from the OP's question, but I've always wondered, how hard does one typically go in a medical stress test (as opposed to a VO2 max test, which I assume means max, since it's called max).

The quick look I just did via Google said that they often go to 85% of max predicted HR, and that they get predicted using 220 - age (which as we know is not that accurate).

I ask because for most of us I'd think that when we're healthy a test at 85% of 220-age would likely be a walk in the park.

Most of us (at this site) are not most people.

The whole purpose of the test is to stress the heart to uncover subtle issues. The end point is not fixed so different doctors may have different protocols. Someone who deals with athletes will surely test different than someone who works in nursing homes.

[frankencrank]

Suggested C2 put a fitness level test in the PM5 years ago never happened. They have a load of data through the online logbook would be really useful. The only thing you can do is rank a row and see where you sit in the field of others in your age group. Probably not a bad indication to be honest just look at the percentile you can hit.

I suggested to apple that they give percentile data rather than low or high fitness assessments. Plus, I am being compared to 60 YO's when they clearly have tons of data on us older folk. They have so far ignored me. Apple probably has more data than anyone. They are trying to put it to good use it would seem but there are some issues.

[frankencrank]

Even that is only a correlation at best. The factor rowing technique/effectiveness is between the effort put in and what the C2 actually measures. And HR is an interesting metric, if only you knew what the max HR actually was (und thus how hard the relative effort was for that person). These are the fundamental issues underlying all these fitness tests: you are working on derived metrics only, most based on sloppy correlations at best. Not the stuff you wan't to advise on their heartattack risk....

Actually, I am not using "derived" metrics but trying to use sound physiology to predict outcome. The idea is exceedingly simple. If I am correct, then clinical correlation would be possible and the idea becomes useful.