Looking for fitness information

[Tsnor]

..All I need is your resting HR (Apple Watch gives that to you but it is simply your HR when fully rested and quiet)...

FWIW you will see a high variance in a person's reported resting heart rate. Plus/minus 5 bpm easily depending on measurement technique used. Same resting heart rate / different reported RHR.

This variance is fine for using RHR to track relative changes ("did this for two weeks and my RHR average went down 2 bpm"). But if you are using an absolute Resting HR in your algorithm you'll need to prescribe exactly how you want resting heart rate measured.

Example:

I check my HRV each morning using eliteHRV app and polar H10 belt. Part of that process reports a 2.5 minute heart rate average when I am awake and resting lying down. That should be a perfect resting heart rate.

My fitbit watch (charge 3) gets 24 x 7 heart rate data and uses an algorithm to produce a daily resting heart rate. The eliteHRV measured 2.5 minute morning HR is consistently 7-10 bpm lower than then fitbit reported resting heart rate.

[JaapvanE]

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.

But you were trained almost 6 decades ago, some stuff might have changed in the meanwhile. My experience is that once a protocol is used in the field, sufficient people with plenty of experience have debated it to great lengths that it works for 90% of the population.

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.

I think that is an extremely ambitious goal. In all honesty, I've read dozens of papers on estimating VO2Max without maxing out the patient in the process, and all are full of assumptions which can't be applied to the general public. In fact, I made the code for Open Rowing Monitor to estimate VO2Max based on a single rowing session, and the short version, we consider it Alpha-code that is based on a decades old paper that defines the step-test without going to HRMax. Firstbeat did some additional stuff (as I recall on HR sinus variability) and can detect Arythmia when it happens. That is where Garmin and Apple stand now, awaiting medical approaval.

When you look at FirstBeat (see https://www.firstbeat.com/en/science-and-physiology/), they are quite capable of measuring much more than you can (HR Sinus variability and amplitude being the most important ones), but they won't say their estimates are the real deal. They are just very good estimates.

Going beyond that, looking for cardiac dysfunctions without stresstesting is also a very active area of research. but without MRI's and stuff like that, I don't think you can. Even in high performance athletes, like soccer players, who are actually stresstested and put under MRI's when bought/sold, you hear of serious undiscovered heart conditions and even deaths during training due to heart failures. And some of these guys sell for a 100 million dollar, so an additional MRI to check if there are no hidden problems is probably worth making the investment.

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).

Anaerobic has its place, although it comes at great cost. And aiming for gold (not so much lions left in the wild...) was one of the reasons for me. But it also is needed for certain endurance sports as some of these athletes run the risk of running out of fat to burn.

[JaapvanE]

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.

Apple doesn't own the algorithm. They didn't do the research. Firstbeat did (technically the founder did for his MSc studies...). And they follow the scientific approach to do the background reading, develop and test and algorithm, have a huge sample group, extract a lot of data and check their assumptions, and licence the algorithm under certain conditions. So when you don't pay enough, or the science simply isn't there, you get low or high.

I guess Polar has most data, followed by Garmin: they have been tracking HR for athletes for decades. But the percentile data comes from data inaccuracy and the fact that you are projecting a statistical average onto a specific case or the science simply is too shaky. That is why you get a percentile, to prevent people from assuming anything. My watch measures my VO2Max walking, running and cycling. My rower can calculate VO2Max in two ways. I know one thing the data tells me for sure, at least four of them are completely wrong.

[frankencrank]

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.

But you were trained almost 6 decades ago, some stuff might have changed in the meanwhile. My experience is that once a protocol is used in the field, sufficient people with plenty of experience have debated it to great lengths that it works for 90% of the population.

LOL. Human physiology doesn't evolve that fast. Nor did I stop being inquisitive after graduation.

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.

I think that is an extremely ambitious goal. In all honesty, I've read dozens of papers on estimating VO2Max without maxing out the patient in the process, and all are full of assumptions which can't be applied to the general public. In fact, I made the code for Open Rowing Monitor to estimate VO2Max based on a single rowing session, and the short version, we consider it Alpha-code that is based on a decades old paper that defines the step-test without going to HRMax. Firstbeat did some additional stuff (as I recall on HR sinus variability) and can detect Arythmia when it happens. That is where Garmin and Apple stand now, awaiting medical approaval.

First, I am not trying to estimate VO2max. Rather, I am trying to estimate METS capacity as that is the basis of the risk assessment. They are related but different. Here is the thought. Cardiac output can increase about 20 times. HR can only increase about 4 times. Two things happen to the heart to increase cardiac output. HR goes up, and stroke volume goes up. Cardiac output (and oxygen delivery) goes up somewhat close to the square of the HR increase. Resting HR is one MET. Double the HR equals 4 METS. Then, there is an amount beyond the anaerobic threshold that most can do, I am saying that is 25%. Put that into a formula and with my resting HR of about 50 and my anerobic threshold HR of about 135 I calculate my METS on an EST to be above 12. Pretty close to real. That physiology applies to pretty much all normal hearts. The only issue is fine tuning the adjustments (does CO really increase with the square or slightly different? etc.) VO2max can be calculated similarly but oxygen uptake decreases beyond the anaerobic threshold so It isn't a straight line. Max HR cannot be changed (or if it can, not easily). Max HR will decrease with age. What can change and the key to this assessment is resting HR. It Is resting HR that is the key to assessing aerobic fitness.

When you look at FirstBeat (see https://www.firstbeat.com/en/science-and-physiology/), they are quite capable of measuring much more than you can (HR Sinus variability and amplitude being the most important ones), but they won't say their estimates are the real deal. They are just very good estimates.

Going beyond that, looking for cardiac dysfunctions without stresstesting is also a very active area of research. but without MRI's and stuff like that, I don't think you can. Even in high performance athletes, like soccer players, who are actually stresstested and put under MRI's when bought/sold, you hear of serious undiscovered heart conditions and even deaths during training due to heart failures. And some of these guys sell for a 100 million dollar, so an additional MRI to check if there are no hidden problems is probably worth making the investment.

I don't care about variability. I am looking at gross physiology and how HR and Stroke volume respond to increased demand. Further, my reasoning only applies to "normal" hearts.

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).

Anaerobic has its place, although it comes at great cost. And aiming for gold (not so much lions left in the wild...) was one of the reasons for me. But it also is needed for certain endurance sports as some of these athletes run the risk of running out of fat to burn.

I am trying assess fitness and risk in ordinary people. While people participate in anaerobic activities aerobic fitness is the key to that assessment.

[frankencrank]

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.

Apple doesn't own the algorithm. They didn't do the research. Firstbeat did (technically the founder did for his MSc studies...). And they follow the scientific approach to do the background reading, develop and test and algorithm, have a huge sample group, extract a lot of data and check their assumptions, and licence the algorithm under certain conditions. So when you don't pay enough, or the science simply isn't there, you get low or high.

I guess Polar has most data, followed by Garmin: they have been tracking HR for athletes for decades. But the percentile data comes from data inaccuracy and the fact that you are projecting a statistical average onto a specific case or the science simply is too shaky. That is why you get a percentile, to prevent people from assuming anything. My watch measures my VO2Max walking, running and cycling. My rower can calculate VO2Max in two ways. I know one thing the data tells me for sure, at least four of them are completely wrong.

What data Apple has that Garmin and Polar do not is what is going on at rest plus response to exercise in both athletes and non-athletes. Just monitoring exercise doesn't tell you much. Apple has that data in millions more people than Garmin or Polar could ever hope for.

[JaapvanE]

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.

Let's be clear about this: even the HR measurement on the watches are derived data. They actually "see" blood moving in microvessels in the skin, assuming the movement is caused by a heartrate. It is a highly intelligent algorithm that does the heavy lifting and makes sense of all situations. A bit more water or sweat and you'r off. A strong powerfull training and your wrist-based measurement is in the woods, never to be seen again. And that isn't an issue, but they are estimates based on skin color, skin thickness (which changes with age) and all other kinds of assumptions. And it is pretty accurate for a healthy white male of around 45 years. It will probably be off for everybody else. When you look at the forum, you see a lot of discussions about HR measurement because of that issue.

Even a simple machine like a rower is a sensor and a huge set of assumptions. As the lead software engineer of the physics engine Open Rowing Monitor, I can tell you: every metric that is on that PM5 is a huge guess, even the time is. The only thing that saves people from losing their marble is that we documented each and every decision, and everybody roughly makes about the same assumptions given the insanity of the alternatives, but we technically we can't even measure flywheel angular velocity or angular acceleration precise enough. Globally, every Rowing machine on the planet uses a power to velocity constant of 2.8 that affects almost every metric on the rower. Why? Because Peter Dreissigacker tested the first model A and decided that was what he needed to end up at the time he was used to on the water. Please note, Peter is an exceptional rower and engineer, and has proven to be quite close to reality only last year. But it took us about 50 years to get to that point. And please note, there is no way in hell to reliably detect a drive and be accurate: either you are robust (Concept2) or you are accurate (RP3), but you can't be both. Still people think that they delivered X watts of power when getting of the rower. They didn't. If they know how to row, in steady state, they probably are close. If you start to do more wild variations, the power calculation on the PM5 loses track (University of Ulm proven that). And that is a quite simple sensor and a bit of physics that is extremely well-known and my 14-year old is taught in school.

And you want to give people advise (or false assurance) based on these vague measurements? Medical approval is a tough process for this reason. In Europe MDR requires a huge stack of paperwork before any type of indication is even given to a consumer about (medical) condition. The law became tougher for this specific reason: people were reassured by a vague app that said it was OK and didn't visit their GP when they should. It is too easy to do a decent estimate that works about 90% of the time, but kills the patient the other 10%.

[JaapvanE]

What data Apple has that Garmin and Polar do not is what is going on at rest plus response to exercise in both athletes and non-athletes. Just monitoring exercise doesn't tell you much. Apple has that data in millions more people than Garmin or Polar could ever hope for.

What do you think Polar and Garmin did the last two decades? They collect the same data like Apple, they just started two decades earlier. FirstBeat was acquired for a reason: the gold isn't in the data itself, it is in the people capable of making the algorithms on top of it.

[frankencrank]

What data Apple has that Garmin and Polar do not is what is going on at rest plus response to exercise in both athletes and non-athletes. Just monitoring exercise doesn't tell you much. Apple has that data in millions more people than Garmin or Polar could ever hope for.

What do you think Polar and Garmin did the last two decades? They collect the same data like Apple, they just started two decades earlier. FirstBeat was acquired for a reason: the gold isn't in the data itself, it is in the people capable of making the algorithms on top of it.

Few people (at least in the old days) collected data 24 hours a day. Plus, their cohort were people who exercised. Apples numbers are huge and involve all sorts. We got our 96 yo mother a watch to alert for falls. They are getting all sorts of other data from her.

It isn't that Garmin and others don't have good data. It is simply that Apple has so much more. Anyhow, as I said at the beginning. All that data didn't help them analyze me correctly which is why I started thinking about it.

[frankencrank]

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.

Let's be clear about this: even the HR measurement on the watches are derived data. They actually "see" blood moving in microvessels in the skin, assuming the movement is caused by a heartrate. It is a highly intelligent algorithm that does the heavy lifting and makes sense of all situations. A bit more water or sweat and you'r off. A strong powerfull training and your wrist-based measurement is in the woods, never to be seen again. And that isn't an issue, but they are estimates based on skin color, skin thickness (which changes with age) and all other kinds of assumptions. And it is pretty accurate for a healthy white male of around 45 years. It will probably be off for everybody else. When you look at the forum, you see a lot of discussions about HR measurement because of that issue.

Even a simple machine like a rower is a sensor and a huge set of assumptions. As the lead software engineer of the physics engine Open Rowing Monitor, I can tell you: every metric that is on that PM5 is a huge guess, even the time is. The only thing that saves people from losing their marble is that we documented each and every decision, and everybody roughly makes about the same assumptions given the insanity of the alternatives, but we technically we can't even measure flywheel angular velocity or angular acceleration precise enough. Globally, every Rowing machine on the planet uses a power to velocity constant of 2.8 that affects almost every metric on the rower. Why? Because Peter Dreissigacker tested the first model A and decided that was what he needed to end up at the time he was used to on the water. Please note, Peter is an exceptional rower and engineer, and has proven to be quite close to reality only last year. But it took us about 50 years to get to that point. And please note, there is no way in hell to reliably detect a drive and be accurate: either you are robust (Concept2) or you are accurate (RP3), but you can't be both. Still people think that they delivered X watts of power when getting of the rower. They didn't. If they know how to row, in steady state, they probably are close. If you start to do more wild variations, the power calculation on the PM5 loses track (University of Ulm proven that). And that is a quite simple sensor and a bit of physics that is extremely well-known and my 14-year old is taught in school.

What you seem to have missed is I don't need to know the power to make my determination. But, I agree, what one sees on the PM5 bears little relationship to what they are probably doing work wise.

And you want to give people advise (or false assurance) based on these vague measurements? Medical approval is a tough process for this reason. In Europe MDR requires a huge stack of paperwork before any type of indication is even given to a consumer about (medical) condition. The law became tougher for this specific reason: people were reassured by a vague app that said it was OK and didn't visit their GP when they should. It is too easy to do a decent estimate that works about 90% of the time, but kills the patient the other 10%.

Is putting the finger on the wrist and counting with a watch derived data? I suppose so.

The data I need is easily obtainable by almost anyone with what is available today. In fact, it was obtainable many years ago using the finger and a stopwatch. Whether it is derived or not as long as it is reasonably accurate that is all that is needed. You are nit picking. Criticize the physiological assumptions. I am all ears.

[JaapvanE]

Is putting the finger on the wrist and counting with a watch derived data? I suppose so.

The data I need is easily obtainable by almost anyone with what is available today. In fact, it was obtainable many years ago using the finger and a stopwatch. Whether it is derived or not as long as it is reasonably accurate that is all that is needed. You are nit picking. Criticize the physiological assumptions. I am all ears.

But you talk about point of lactation. Do you consider that easy to measure? It can be estimated through 85% of MaxHR (but MaxHR is often estimated) or measured through blood samples. You can talk about "fatigue" but that is an extremely vague term where typically most people only recognise it when it is way too late....

[frankencrank]

Is putting the finger on the wrist and counting with a watch derived data? I suppose so.

The data I need is easily obtainable by almost anyone with what is available today. In fact, it was obtainable many years ago using the finger and a stopwatch. Whether it is derived or not as long as it is reasonably accurate that is all that is needed. You are nit picking. Criticize the physiological assumptions. I am all ears.

But you talk about point of lactation. Do you consider that easy to measure? It can be estimated through 85% of MaxHR (but MaxHR is often estimated) or measured through blood samples. You can talk about "fatigue" but that is an extremely vague term where typically most people only recognise it when it is way too late....

Point of lactation?!!!

What one needs to "measure" is both the resting HR and the "anaerobic threshold." Resting HR will be pretty stable (assuming one isn't sick or not rested (as athletes sometimes are). Apple Watch actually gives it for you and it is pretty close (you know, close enough for government/medical work). Apple Watch tells me my resting HR is 50-51 even though I am sometimes down to the low 40's during sleep (it was about 35 when I was really fit). And, my sustainable HR can vary a bit also but is usually 130-135 (My max is 165-170 - when climbing hills on my bike - so about 78% of my max). All the person has to do is put on some walking shoes and go out and see what they can keep up for 10 minutes and see what their HR is. All of these values can change from day to day depending on a lot of things but they do not normally change dramatically unless sick and, yes, they are easy to gather for almost everyone. If someone is going to get something wrong, they will probably underestimate their anaerobic threshold by staying too comfortable or overestimate their resting HR by taking it after coffee or sex making their fitness look less than it really is.

This is not rocket science. Gather a couple of simple physiological parameters and put them in a formula. I am not sure what you are criticizing. I have asked you to comment on the physiology I am using to make the assessment and you haven't said anything.

You have all the data I am asking for. Why don't you give me what you have and let me see how close I get to your ability.

[frankencrank]

..All I need is your resting HR (Apple Watch gives that to you but it is simply your HR when fully rested and quiet)...

FWIW you will see a high variance in a person's reported resting heart rate. Plus/minus 5 bpm easily depending on measurement technique used. Same resting heart rate / different reported RHR.

This variance is fine for using RHR to track relative changes ("did this for two weeks and my RHR average went down 2 bpm"). But if you are using an absolute Resting HR in your algorithm you'll need to prescribe exactly how you want resting heart rate measured.

Example:

I check my HRV each morning using eliteHRV app and polar H10 belt. Part of that process reports a 2.5 minute heart rate average when I am awake and resting lying down. That should be a perfect resting heart rate.

My fitbit watch (charge 3) gets 24 x 7 heart rate data and uses an algorithm to produce a daily resting heart rate. The eliteHRV measured 2.5 minute morning HR is consistently 7-10 bpm lower than then fitbit reported resting heart rate.

Sigh. Apple Watch will give you a rhythm strip if you really want an accurate resting HR. Of course, HR varies with respiration so what to do now? Apples calculated RHR is a little bit more than what I usually see in the mornings too, by a few beats, not 7-10. 7-10 is bizarre and I wold never trust it. Trust what you are measuring yourself.

People think medicine is a difficult science. It may be difficult but the goal of most doctors is "good enough" and the enemy of "good enough" is "perfect." So, is my idea, good enough? Perhaps. Be nice if I had some data to check.

[Mike Caviston]

First, I am not trying to estimate VO2max. Rather, I am trying to estimate METS capacity as that is the basis of the risk assessment. They are related but different. Here is the thought. Cardiac output can increase about 20 times. HR can only increase about 4 times. Two things happen to the heart to increase cardiac output. HR goes up, and stroke volume goes up. Cardiac output (and oxygen delivery) goes up somewhat close to the square of the HR increase. Resting HR is one MET. Double the HR equals 4 METS. Then, there is an amount beyond the anaerobic threshold that most can do, I am saying that is 25%. Put that into a formula and with my resting HR of about 50 and my anerobic threshold HR of about 135 I calculate my METS on an EST to be above 12. Pretty close to real. That physiology applies to pretty much all normal hearts. The only issue is fine tuning the adjustments (does CO really increase with the square or slightly different? etc.) VO2max can be calculated similarly but oxygen uptake decreases beyond the anaerobic threshold so It isn't a straight line. Max HR cannot be changed (or if it can, not easily). Max HR will decrease with age. What can change and the key to this assessment is resting HR. It Is resting HR that is the key to assessing aerobic fitness.

A few points:

1) Cardiac Output can increase how many times? Resting CO is about 5 L/min. During max exercise, healthy people can generally get to 20 L/min, and elite endurance athletes to 25-30 L/min. Where does 20x come from?
2) The MET, or Metabolic Equivalent, is the amount of O2 consumed at rest. It can be measured directly, but for exercise prescription purposes is assumed to be 3.5 mL O2/kg/min and tables comparing the intensity of different activities are just using multiples of this value. How accurately can resting HR estimate a MET? Two people of equal mass will consume similar amounts of O2 even if one has a resting HR of 40 and the other a resting HR of 70.
3) I won't even go into the notion of "anaerobic threshold HR" and all the problems associated with that.

So, I don't see how resting HR is going to have more than a loose correlation with "aerobic fitness", however that term is being used (VO2 max? Performance? Mortality risk?)

[frankencrank]

First, I am not trying to estimate VO2max. Rather, I am trying to estimate METS capacity as that is the basis of the risk assessment. They are related but different. Here is the thought. Cardiac output can increase about 20 times. HR can only increase about 4 times. Two things happen to the heart to increase cardiac output. HR goes up, and stroke volume goes up. Cardiac output (and oxygen delivery) goes up somewhat close to the square of the HR increase. Resting HR is one MET. Double the HR equals 4 METS. Then, there is an amount beyond the anaerobic threshold that most can do, I am saying that is 25%. Put that into a formula and with my resting HR of about 50 and my anerobic threshold HR of about 135 I calculate my METS on an EST to be above 12. Pretty close to real. That physiology applies to pretty much all normal hearts. The only issue is fine tuning the adjustments (does CO really increase with the square or slightly different? etc.) VO2max can be calculated similarly but oxygen uptake decreases beyond the anaerobic threshold so It isn't a straight line. Max HR cannot be changed (or if it can, not easily). Max HR will decrease with age. What can change and the key to this assessment is resting HR. It Is resting HR that is the key to assessing aerobic fitness.

A few points:

1) Cardiac Output can increase how many times? Resting CO is about 5 L/min. During max exercise, healthy people can generally get to 20 L/min, and elite endurance athletes to 25-30 L/min. Where does 20x come from?
2) The MET, or Metabolic Equivalent, is the amount of O2 consumed at rest. It can be measured directly, but for exercise prescription purposes is assumed to be 3.5 mL O2/kg/min and tables comparing the intensity of different activities are just using multiples of this value. How accurately can resting HR estimate a MET? Two people of equal mass will consume similar amounts of O2 even if one has a resting HR of 40 and the other a resting HR of 70.
3) I won't even go into the notion of "anaerobic threshold HR" and all the problems associated with that.

So, I don't see how resting HR is going to have more than a loose correlation with "aerobic fitness", however that term is being used (VO2 max? Performance? Mortality risk?)

You might want to check your data. Resting VO2 is about 250 ml/min in a 70 kg man. At exercise that man can burn 5-6 L/min. Oxygen carrying capacity of the blood doesn't change. If CO can only increase 4-6 times then the max mets possible would be 4-6 and we would all be striving to get to a 10 hour marathon.

The met is what your body is receiving and using at rest. I believe it a safe assumption that whatever your HR is at rest it is delivering exactly 1 met.

[gvcormac]

When you folks say CO, I assume you mean CO2.

Basically, this entire thread is navel-gazing. There are many epidemiologists and public health professionals who are interested in this problem, and I don't think that "institutional review" or cardiologist complacency is the major impediment to predicting health outcomes from measures of fitness.

My impression -- and this is just my impression that you can refute with properly controlled study results -- is that health outcomes improve dramatically with some level of fitness, but not particularly with athletic levels of fitness.