Accuracy of Garmin Wrist based HR sensor

scott dinhofer

My daughter, Ally, is 19 and training for her first marathon. She's slow... but steady, 12' miles.. she uses a garmin forerunner with wrist based HR. She doesn't really run by HR yet. but I've been watching it and noticed it's quite high (170 average for a recent 10 mile run in high, high humidity. (https://www.strava.com/activities/1785973890) please do not follow her or give her kudos or comments, she'll get mad at me.

curious if her HR is THAT high (19 yr old women vs 53 YO man) or if the Garmin wrist HR just reads high?

thanks

Paul Curtin

I run with the Garmin Forerunner 235.  The wrist-based HR readings were horribly wrong, on the high side.  The data was worthless.  I shut off the optical HR read and linked it to my Wahoo KICKR HR strap.  I also use the Fitbit Ionic.  Same HR issue what that device

Al Truscott

She has 3 or 4 reasons for a higher heart rate. Age, gender, weight, and relatively short time to develop cardiac "fitness", meaning a larger heart. 170 sounds ball park to me. Check out online calculator like:

http://nowlin.com/heartrate.htm

John Withrow

I agree with @Paul Curtin    My normal run HR with my TICKR strap is in the ~120-140 range at mid-high 8's pace.  If I'm pushing harder or it gets super humid, I can see it creep up to the low 150's.  If I'm in the ~160's for any measurable amount of time I know explosion will be upon me soon.   Last weekend my HR strap died, so I did my longer run with the wrist HRM on my Garmin 935.  I was regularly seeing numbers in the ~170's and 180's.   I can last a total of ~45s with a HR at 172.  So clearly I didn't run ~2 hrs like that...    Assume the HR data directly from the watch, I assume it is useless (for me, but ymmv)...   here's my file from this weekend's run I was referring to:  https://www.strava.com/activities/1783053932

John Katsoudas

My personal experience with Garmin optical HR is that it's not terribly accurate, but the inaccuracy manifests as 'lumpy' readings, rather than consistently high readings.  Not sure if my, errr... hirsuteness plays a role in this.

Gordon Cherwoniak

I have no experience with the wrist HR monitor's.  If it's consistent then then the number is just higher. Given what the John's and Paul have said it may not be very consistent which is an issue.  Only way to know is put on a chest strap and see.

I fit the 220-age HR fairly closely when younger now I can push my HR up  about 9 beat higher than the max at 46 year old.   While only a generalization if her max HR is around 200, 170 is still 30 or so beat from the max.  Further you mention high, high humidity so that will push up the HR.  Finally most of her elevation happened in the first 3.6 miles which will contribute to pushing up the HR early.

 

Tim Sullivan

I think that sounds about correct. I notice that with the Garmin optical HR that the initial few minutes may be incorrect by reading too high.  After a few minutes, the HR reads correct at least 98% of the time.  Occasionally it will freak out, but not very often.  You might want to ask her to tighten the watch so its snugly on her wrist when she runs. I tighten mine up for the run, and then loosen the strap after the run. The HR for your daughter seems very reasonable. 170 doesn't sound high to me at all.

Derrek Sanks

I guess I'm the odd ball out. Two weeks ago I was gifted a Forerunner 735 with optical HR. Since I wasn't confident in the optical HR accuracy, on my first four runs with the 735 I had my trusty 910XT (paired to my Wahoo Tickr) on my other wrist. I was surprised to see the same average HR for the total run on both watches. I was convinced for a couple days, then repeated this test a few days later because I started to question the accuracy and again, same results. I did notice the optical HR responds slower than the chest strap. For example, when I stop running it takes the optical 3-4 seconds to start dropping whereas the chest strap starts dropping off sooner.  

As far as heart rates go, x2 what @Al Truscott said. Females typically have a higher HR. I know a female endurance runner...under 25 yrs old and has completed 2 marathons and an ultra. Her HR averages in the mid to high 160s, from 3 to 16+ miles at an easy/Z1 pace (e.g. 11:30 pace). Doctors told her HR was normal.

Stephen Cogger

Have her wear a chest strap and compare. It’s not the same, but I have an apple watch which reads heart rate. It’s ridiculously high when I use it for a run. The difference between a garmin chest strap and the apple watch can be as much as 50bpm. I think it has to with motion as the watch can move more giving inaccurate results even if I tighten it to uncomfortable levels. My watch always reads high. Of course, this is not a garmin watch...

Jeff Horn

Nope nope nope.  I have fenix 5 and shut down the optical about 3 months after getting it.  At the time I was happy to get rid of HR strap, but the optical is at least 15 beats higher, doesn't improve with duration of exercise.  

Trish Marshall

I had high hr on a treadmill in a warm gym with just the 935 optical hr.  I've done a few runs recently strapless where my hr and rpe were pretty close to when wearing a strap.  I think my experience is more like Tim's then Jeff's and John's.  

Jorge Duque

I have been using the optical hr (forerunner 235) for a year now and the readings are quite consistent with the strap. The only complaint is that sometimes it goes crazy for short periods of time, but then it goes back to normal readings

Rich Stanbaugh

Scott - My wrist HR is pretty similar to my chest HR as long as I keep the strap tight. The sensor seems to be pretty sensitive to light "leakage" and if the strap is loose, it gives some flaky numbers. I tested mine vs a strap (using both simultaneously) and had virtually the same numbers as long as the wrist strap was snug.

The Strava file seems reasonable - HR increased when climbing and decreased after.

I can tell you that people have wildly different HRs. The old adage about "220 - age" is garbage.  Here is a HR file for me MondayL https://www.strava.com/activities/1786318786. This was a progressive run where I started easy and pushed a little more along the way and I still averaged 164 - My peak HR for the year is 199a and I will average 172+ for a half marathon, and I will be 52 soon. Anna also has a high HR (no age disclosures!). In addition to the 3-4 points that Al added - I would just add that people are different. I've never had a better explanation for it.

scott dinhofer

thanks all, really helpful and insightful info in here. 
especially liked @Derrek Sanks' side by side comparison!

Jonathan Brown

Ok, i am a really bad example.  My HR is typically in the 160 to 180's on my runs. I always have had a high HR.  I use both chest strap and garmin 935.