Heart rate zone calculation by GC

Hi All...

I checked my heartrate zones on Garmin Connect yesterday and was surprised to see that Garmin thought my max heart rate is 185bpm. Using the standard formula, I would expect it to be 170 (220 - my age of 50). SOme research and I found a post somewhere saying GC uses some formula based on my resting heart rate. Thing is, I don't recall telling GC what my resting heart rate is. So what's going on?

Thanks...

Not sure where it would have gotten the numbers. Did you put anything in the settings (there is a place to enter this info)?

In any event, my real purpose for replying is to say that using an aged based formula (whether 220-age or one of the other formulas out there) to determine MHR and thus zones is not recommended. While the formulas may (or may not) have some validity as averages, they can be wildly inaccurate for any particular individual. It's like saying the average man wears a 42 regular suit, so that's what everyone has to wear. To have meaningful zones you have to determine your actual MHR or at least follow one of the protocols out there to reasonably estimate it or your lactate acid threshold. Kind of beyond the scope of this forum, but there is a lot of info out there on this if you search for it. For example, you can determine your threshold HR, using the Joe Friel method: 30min all out, take LTHR as average over last 20. This is for cycling, but similar tests exist for running.

Not sure where it would have gotten the numbers. Did you put anything in the settings (there is a place to enter this info)?

In any event, my real purpose for replying is to say that using an aged based formula (whether 220-age or one of the other formulas out there) to determine MHR and thus zones is not recommended. While the formulas may (or may not) have some validity as averages, they can be wildly inaccurate for any particular individual. It's like saying the average man wears a 42 regular suit, so that's what everyone has to wear. To have meaningful zones you have to determine your actual MHR or at least follow one of the protocols out there to reasonably estimate it or your lactate acid threshold. Kind of beyond the scope of this forum, but there is a lot of info out there on this if you search for it. For example, you can determine your threshold HR, using the Joe Friel method: 30min all out, take LTHR as average over last 20. This is for cycling, but similar tests exist for running.

Thanks for the reply, I appreciate you sharing that! I basically wanted to get something in there, for lack of anything better, and I was surprised to see that Garmin had either a default set of zones or had calculated zones for me. So i was just wondering if I should expect those to be at all accurate. Probably not. I'll do some research about Joe Friel and other methods of testing it, thanks!

Thanks for the reply, I appreciate you sharing that! I basically wanted to get something in there, for lack of anything better, and I was surprised to see that Garmin had either a default set of zones or had calculated zones for me. So i was just wondering if I should expect those to be at all accurate. Probably not. I'll do some research about Joe Friel and other methods of testing it, thanks!

There is a box in the hr settings for resting rate. Did you put this in and forget you did so? What device do you have? Some track RHR (mine does not). Perhaps those that do automatically input the number. By the same token, if you didn't input the 185 as your MHR, did you hit that during one of your activities? Maybe the device uses the highest number recorded absent user input. Not sure about these things.

If you enter MHR and RHR, GC will compute zones using heart rate reserve (HRR). With this method, instead of using % of MHR, it uses (% of (MHR- RHR)) + RHR to determine zones. Some think this is a better method. You can manually adjust the zones.

BTW, Friel wrote "The Cyclist's Training Bible" and other books on cycling. Many in cycling circles (pun intended) do, indeed, regard this as the bible for cycling training. He regards LTHR as better for determining zones since different people can hit this at differing %ages of MHR. So if zones are base only on MHR, one person could be aerobic and one anaerobic at the same % of MHR. LTHR changes based on training; MHR does not (altho it may seem so as it it hard to hit and someone in average or poor condition probably won't be able to push hard enough to reach it).

There is a box in the hr settings for resting rate. Did you put this in and forget you did so? What device do you have? Some track RHR (mine does not). Perhaps those that do automatically input the number. By the same token, if you didn't input the 185 as your MHR, did you hit that during one of your activities? Maybe the device uses the highest number recorded absent user input. Not sure about these things.

If you enter MHR and RHR, GC will compute zones using heart rate reserve (HRR). With this method, instead of using % of MHR, it uses (% of (MHR- RHR)) + RHR to determine zones. Some think this is a better method. You can manually adjust the zones.

BTW, Friel wrote "The Cyclist's Training Bible" and other books on cycling. Many in cycling circles (pun intended) do, indeed, regard this as the bible for cycling training. He regards LTHR as better for determining zones since different people can hit this at differing %ages of MHR. So if zones are base only on MHR, one person could be aerobic and one anaerobic at the same % of MHR. LTHR changes based on training; MHR does not (altho it may seem so as it it hard to hit and someone in average or poor condition probably won't be able to push hard enough to reach it).

Okay I have been checking, on the web based panel there is a place under Settings -> Personal Information where VO2 Max for cycling and running can be entered, and I left both those blank since I don't know the answer. I now see there is also LTHR and LT Pace, I also left those blank for the same reason. Doing a little Googling, I see the phone app has a place where the training zones can be configured and in that place I can enter resting HR, but I had never seen that before, and it says zero. I can also enter the max HR, which is set to 185.

I did notice that the 90% zone starts at 167, which is the most I have hit since I got the watch, just doing elliptical (too cold for me to go out and run - I'm a wimp). Probably just a coincidence though.

I just ordered Friel's Total Heartrate Training book on Amazon. Saw it used in good condition for about $6.00 with free shipping. It seems like an old book though, could it be outdated?

Thanks for your help!

EDIT: Oh, I have a VivoActive.

Not familiar with that book, but I don't think its age should make a difference. Not aware that much has changed in 10 years. Newer books probably talk about new technology more,including power meters. For figuring out zones it should tell you what you need to know.

Just to agree with the above really and the inaccuracy of 220 - age - for me that gives an MHR of 160 - I know that in interval training I can push my HR to about 180 so my MHR is probably about 185.

If I were to use 160 as MHR then my target HR training zones would be ridiculously low.

Just to agree with the above really and the inaccuracy of 220 - age - for me that gives an MHR of 160 - I know that in interval training I can push my HR to about 180 so my MHR is probably about 185.

If I were to use 160 as MHR then my target HR training zones would be ridiculously low.

Yeah I'm going to have to get out on the track and wear myself out to get a real number...

One thing people should realize is that a high mhr ( as opposed to a lthr that is a high % of mhr) says nothing about fitness level. It is just a number you need to know to work from. I once knew a guy in his 20s who qualified for the US Olympic marathon trials. He had a mhr about 160.

It is true though that the formulas seem more often low than high. I think this because in many of the studies used to derive the 220- age formula, people weren't motivated to work hard. They just took people off the street, put them on treadmills and said go as hard as you can. It hurts to get to mhr and you have to be motivated. For more info see:http://www.nytimes.com/2001/04/24/health/maximum-heart-rate-theory-is-challenged.html?pagewanted=all

There's a lot of misconception about the 220-age as an indicator of max HR, but the reality is that it's often a good first step. Yes, some are higher and some are lower, but there are few outliers of any significance. For most of us they will do when starting out, but is likely to underestimate HRmax for adults over 40, which is not necessarily a bad thing for older people beginning exercise.

For more options take a look at this site - http://www.brianmac.co.uk/maxhr.htm

It gives you a range numbers that you can look at individually or take the average of the numbers presented and that will provide a useful indicator to begin with. Compare with a maximal HR test at some stage and see what you get.

I get a result that is a few beats lower than what I can actually achieve but not by much.

This study presents another option - http://content.onlinejacc.org/article.aspx?articleid=1126908

If you really want to know what your max HR is then you need to test for it either by yourself or in a lab.