Bad heart rate accuracy or am I a freak?

[KRemick]

I just recently got a Blaze and have been using the heart rate monitor, especially during my work-out. My resting rate is 63 bpm, which is normal, but my rate during exercise is way high. I'm 53, so my max heart rate should be around 167 - 170 (depending on method). My max heart rate while walking today was 183 bpm. I was walking quickly but not short of breath or working particularly hard. My heart rate falls considerably when I lift weights (~120 bpm), which has me working harder. I've had my genes done and have 2 chromosomes for fast twitch muscles. Could that have anything to do with it? Slow twitch activity takes more blood flow because I have fewer slow twitch fibers? Or can the Blaze's heart rate monitor be that far off? What's going on? Anyone have any ideas?

[shipo]

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@KRemick wrote:

I just recently got a Blaze and have been using the heart rate monitor, especially during my work-out. My resting rate is 63 bpm, which is normal, but my rate during exercise is way high. I'm 53, so my max heart rate should be around 167 - 170 (depending on method). My max heart rate while walking today was 183 bpm. I was walking quickly but not short of breath or working particularly hard. My heart rate falls considerably when I lift weights (~120 bpm), which has me working harder. I've had my genes done and have 2 chromosomes for fast twitch muscles. Could that have anything to do with it? Slow twitch activity takes more blood flow because I have fewer slow twitch fibers? Or can the Blaze's heart rate monitor be that far off? What's going on? Anyone have any ideas?

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There are no "should be" maximums when it comes to heart rate; all of the formulas are horribly flawed.  I'm nearly ten years older than you and I can push my heart rate up into the low 180s when I'm out on a long run and push the pace up a long grade.

[bbarrera]

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@KRemick wrote:

I just recently got a Blaze and have been using the heart rate monitor, especially during my work-out. My resting rate is 63 bpm, which is normal, but my rate during exercise is way high. I'm 53, so my max heart rate should be around 167 - 170 (depending on method). My max heart rate while walking today was 183 bpm. I was walking quickly but not short of breath or working particularly hard. My heart rate falls considerably when I lift weights (~120 bpm), which has me working harder.

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Don't overthink it, the Blaze is generally good at resting HR but like most optical HRM on the wrist can easily be wrong while exercising. The Blaze and other wrist HRMs are better at some activites, like steady state walking or running, and can be really bad at other activities like weight lifting or boot camp (anything involving flexing of the wrist, as it restricts blood flow).

So the wrist is an error prone location for detecting HR while moving, and is easily impacted by how you wear it and your physiology. Since you can't change your physiology, the first thing to do is review wearing tips:

http://help.fitbit.com/articles/en_US/Help_article/1565/?l=en_US&fs=Search&pn=1#ImpactsAccuracy

Blaze is generally good at HR while walking and steady-state running, so hopefully by adjusting the location before walking you'll get better results. However there is a small chance your physiology doesn't work well with optical HRMs, but that is not typical.

I have the same problem while weight lifting with Blaze, Surge, and Apple Watch. Never met an optical HR monitor that accurately measures HR while lifting or on the rowing machine for 10 minute warmup. 

[bbarrera]

Also, cold weather reduces blood flow under the skin of your wrist. Depending on your physiology, that can make it difficult for Blaze to estimate your HR while walking or running during cold weather.

In these types of situations, its not unusual for optical HRM to falsely use your walking/running pace as HR (because the rhythmic motion of your pace is a stronger 'signal' than blood movement under the skin due to cold weather or physiology).

[KRemick]

Since I'm old and clumsy, I walk inside, so the temperature is uniform throughout not only the session, but the year. LOL, at -20 I don't like to walk to my car much less do a work-out out there. 

[J-flex]

It's seems that my earlier response mysteriously disappeared.  I too find the HR inaccurate and don't rely on my Fitibt products for accuracy.   When I want to measure my heart rate I will use my Polar chest strap.  I find that provides the most accurate HR results. 

[KRemick]

I'll keep that In mind, however becauase I'm old and clumsy, I do my workout inside. LOL, I don't even like walking to my car at -20 much less working out.

[KRemick]

I decided to do some experimentation today during the work out, and as a result think there may be something to the fast/slow twitch tissue thing. When I had my heart rate up at 183, I went from a fast walk (slow twitch) to all out sprinting (fast twitch) for about 75 yards. My heart rate actually went down. I did this 3 times to be sure, and it dropped each time, with an average of -11.67 bpm. I looked on google and google scholar and found that no-one has looked at the difference between heart rate profiles of people with 80% fast vs slow twitch muscles performing different tasks. Any medical types need a master's project?

[AdamMSC]

The thing is probably just wrong... if you are exerting more effort, your heart rate will generally go up. Try it with a chest based monitor. Also, you said that you had your heart rate up to 183 ( which is getting up towards a max heart rate) and then sprinted... that would certainly raise your heart rate some, but the room for error there is so small. The device probably missed it because it was for such a short duration and has trouble keeping up at times.

[KRemick]

That's the thing about having 80% fast twitch muscles - sprinting takes less effort than jogging or walking fast. My lungs work harder, but my muscles don't. I'm more conserned with my lack of agility and putting a foot down wrong than I am muscle fatigue; at least for the distance I'm using.

[KRemick]

I have just ordered a chest heart rate monitor to use as a check on the fitbit one (I was unaware that you could get one cheaply). My theoretical maximum heart rate is 167-170 bpm (depending on method) and having a regular occurrence of numbers higher than that means there is something wrong with either the theory or the data taking. As a scientist, my main consern is accuracy. Garbage in garbage out applies to data analysis too. That said, I question the theory as well as the data taking. Not seeing any studies where fast and slow twitch muscles were separated out means that something important could be averaged out. From my web reading, it seems the data is kind of wild. That's usually an indication that you have multiple populations mixed together. Combining people with 80% fast twitch, 80% slow twitch and 50%/50% could be responsible. I'd really like to see a study with them separated out.

[shipo · Accepted solution]

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@KRemick wrote:

I have just ordered a chest heart rate monitor to use as a check on the fitbit one (I was unaware that you could get one cheaply). My theoretical maximum heart rate is 167-170 bpm (depending on method) and having a regular occurrence of numbers higher than that means there is something wrong with either the theory or the data taking. As a scientist, my main consern is accuracy. Garbage in garbage out applies to data analysis too. That said, I question the theory as well as the data taking. Not seeing any studies where fast and slow twitch muscles were separated out means that something important could be averaged out. From my web reading, it seems the data is kind of wild. That's usually an indication that you have multiple populations mixed together. Combining people with 80% fast twitch, 80% slow twitch and 50%/50% could be responsible. I'd really like to see a study with them separated out.

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The formula are garbage in many cases.  I am a distance runner as well as a coach; the runners I coach rage from post-college professionals through old farts like me, and in literally every case, we can all easily exceed our theoretical maximum heart rate.  Case in point, my very first run with a heart rate monitor, back when I was a couple of weeks shy of turning 58 (giving me a maximum calculated heart rate of 162), I ran a 9-mile loop from the office over a very hilly course in 77 minutes; my *AVERAGE* heart rate was recorded as 161 and my heart peaked up in the high 170s during several of the hill climbs.

Long story short, ignore the maximum heart rate formulas, for many folks they are irrelevant.  If you *really* need to know (and I rather doubt you do for anything other than curiosity) then the best way is to have a doctor give you a stress test.

[KRemick]

LOL, you are right about really NEEDINg to know. It's more of an OCD itch. Things NEED to be explained in a rational manner or I keep pokin at them. That'm much of the reason I became a scientist.

[AlejandraFitbit]

Hello all, I hope you are doing fine!  I would like to know if you keep having problems with your heart rate information? If you do, I recommend visiting the link provided in a previous post and also check the Things You Can Do To Make The Blaze More Accurate post, where our friend @bcalvanese is providing really good tips.

Catch you later.