Heart rate accuracy during exercise

[Buckb]

Same problem as many posted on accuracy during exercise. Comparing with chest strap on Garmin and Polar (alternate days) on elliptical. Chest strap and elliptical heart rate monitor are identical. Surge is much higher on average BPM, like 20+, and extremely high on max bpm, like 50++. With other exercises Surge and chest strap have wide variance. Have tried all the recommendations (3 fingers) and even underside of wrist. Only time tracked closely was when held hand on handle to minimize any movement. Been trying this since Christmas and very inaccurate foe exercise.

I see many on discussion board having trouble like me, and others saying works fine and/or after they made some adjustment in wearing or reset it worked fine.

Trying to determine if have defective Surge, or this what you get with the Surge. Several friends asked about it, and I really want to have it work, but can't recommend it at $250 at this point.

I don't expect it to be as accurate as chest strap, but expect it to be within 5 bpm avg without huge swings in max bpm that put me in the heart attack range.

Solutions ? Defective? or flawed design?

[MarreFitbit]

Welcome to the Fitbit Community @Buckb, hope you're doing great my friend ! Are you running or walking when doing the elliptical?

Have you tried restarting your Surge? 

Catch you later! 

[Buckb]

Yes, several times

[MarreFitbit]

Thanks for confirming that my friend @Buckb! My best suggestion would be to get in touch with Customer Support directly, so they can give you a hand on this. 

Don't forget to mention all the steps you've done so far to avoid getting the same ones already attempted.

Good luck! 

[SunsetRunner]

I to have erratic heart rates, first with HR then bought a Surge. Seemed to work well for awhile then not so I reset and again worked well but for a shorter time.
Walking from a 3.5 to 3.8 and incline from 1 to 3 my HR varies 70 bpm. What used to be in cardio much of the time is now mostly fat burn. When i got the HR and also got below 200lbs I started running to get to peak but arthritis in knees came back so try and spend as much time in cardio as possible to maximize calorie burn for trainer and cut down some on time spent. I've tried all positions both wrists and resetting. Really don't think I should have to wear another monitor...won't help my problem here with trainer anyway.

[Buckb]

Gave up and sent back for refund. All other trackers I have checked out seem to have same issues as Surge with wrist/arm HR measurement during intense workouts. I will stick with chest strap on Garmin or Polar until the technology gets there.

[Bmarthasti]

Similar issues with new charge hr- 10k run max hr of 169, then walking the dog max of 175. Not very accurate - I think the best you can hope or shoot for is trying to stay in the ranges they give you until the tech gets better- some day they may have an implantable -who knows

[SunsetRunner]

Today my Surge recorded a 187 avg bpm during the first 10 minutes of a 100 minute treadmill session and that was what I consider my warm up! The rest averaged out at 131bpm. Speed of 3.4 to 3.7 whole time with incline never over 4. This keeps getting worse. I've tried everything, just keep hoping for an update to get this relatively close would be all I would expect.
During an elliptical session the machine kept warning me of "heart rate to high" but Surge was 130 to 135 and I felt ok so kept going.

[Buckb]

Stopped fighting it and returned unit. It appears all wrist based monitors out there have same issue with exercise heart rate measures. Back to chest strap. Unfortunate Fitbit and others do not qualify this issue upfront to buyers.

[mhaar02]

HELP! I just purchased my surge today set it up this morning and had it placed on the top of my arm 3 fingers away from the wrist bone. I'm very dissapointed in this product so far, coming from a polar fitness ft80 heart rate monitor. I was satisified with the operation of the polar fitness hr monitor, just wanted to drop the chest strap. My first use of the surge in exercise this evening I did standing shoulder press and power cleans. After completing a set of power cleans my watch only said I was at 94 heart rate. When I had my hand at my hips then checked it, I noticed my heart rate went up 10-20. When I use my polar fitness hr monitor this is an easy 160ish exercise for me. At the end of my workout my max heart rate that i saw was 135. Very dissapointing so far, help!

[bbarrera]

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@mhaar02 wrote:

My first use of the surge in exercise this evening I did standing shoulder press and power cleans. After completing a set of power cleans my watch only said I was at 94 heart rate.

---

mine is usually 60-80bpm while lifting weights

[mhaar02]

That doesn't seem right either. My resting heart rate is as low as 61 so far.

[robertthebob1]

This is my review on the CU site about band tightness:

In a two week series of four mile runs, I measured the Fitbit Blaze heart rate accuracy against two chest strap ECG monitors, the Omron HR-100C and the Polar H7 (the same sensor used by CU) at three tightness fittings, just above my wrist bone, each differing by one band notch. After a ten minute warm-up: the least tight; tighter; and most tight fittings showed an average difference (X) from the Omron and a standard deviation (s) of 0.6, 2.4; 0.9, 1.6; and 1.0, 1.5 beats per minute (bmp), respectively. The overall X and s using the Polar H7 with the most tight Blaze band fitting was 1.2 bpm and 1.0 bpm, and in relatively high intensity (for me) runs between 140 and 150 bpm the X and s was 1.2, 0.6. It was not necessary to stop and let the Blaze readings settle before recording numbers. The most tight fitting was not as uncomfortable as the chest strap during a run. The conclusions are that: on my wrist, the FitBit Blaze must be quite tight to obtain an accurate reading, it is within 2 bpm of the Polar H7 most of the time, and it maintains this accuracy at least up to 150 bpm with no change.

A greater improvement was seen in the warm-up accuracy. I had reported in my review of the Blaze on the REI site in March that in the first ten minutes of exercise (the warm-up) the X and s with the Omron was 2.7 bpm and 9.5 bpm. (Similar results were obtained with my Surge.) These results were obtained with the least tight fitting. In my measurements over the past two weeks using the more tight and most tight fittings, the X and s from the Omron were: 3.2 bpm and 4.1 bpm; and 0.9 bpm and 1.9 bpm respectively. So the average difference goes from 2.7 to 3.2 to 1.9 bpm as the band becomes tighter, while the deviations (statistical errors) in these numbers goes from 9.5 to 4.1 to 1.9 bpm. With the Polar H7 the X and s using the tightest fitting was 1.4 bpm and 1.3 bpm, without stopping to take readings as described in the manual. A tighter band yields significantly more accurate readings, and in my case the Blaze is almost statistically indistinguishable from the Polar H7, even at 145 bpm.

I feel embarrassed that I assumed for three months that my FitBit was tight enough. I thought I had conformed to the directions in the manual with one exception; I couldn't get a good fit on my arm at two or three fingers above my wrist bone. I had to settle on a position just above my non-dominant wrist bone, even though my wrist is not especially fleshy. I even stopped and waited for the heart rate to settle before taking each reading. The conclusion I draw here is that the FitBit manual is inadequate in its directions for how tight to wear the band during exercise.

My suggestion is to view the FitBit from the hand-side and push up on the band from the bottom with your thumb and index finger. If you see green light, the sensor is subject to light leaks and movement artifacts and the band is not tight enough for strenuous exercise. I've not had a problem with reduced circulation, and it appears I could go even tighter. In my preliminary tests in exercises where the wrist is flexed: push-ups, weight training, and bike riding, I've seen very good results, but I have no statistics yet. I am a retired biophysicist and have accepted no compensation of any kind for this review.

[shaunie2fly]

Hey Buckb,  I also have the Polar A360 and in my opinion it is more accurate than the Surge in running and waaay more accurate during weight training.  Im quite bummed actually because its not a bad device build and feature wise I feel like swinging back to the A360 now but im going to give the Surge a chance for at least a month.

Seems like the heart rate algorithm takes to long to get to the correct heart rate during high intensity fast rep. training and by the time it gets there your heart rate has changed.

On first experience I suggest fitbit makes a chest strap option and spends a bit more time getting the heartbeat algorithm right.

I've only used the watch for 2 training sessions so far so maybe im jumping the gun but I'll be sure to update my experience over the next few weeks and I'll do a blog comparison between Polar A360 and Surge on HR accuracy.

[Buckb]

I sent the Surge back, but recently bought the Blaze. Blaze does better on heart rate than Surge, but only while cycling. About spot on to Polar chest strap and picks up GPS info from iPhone if on. However, any exercise with hand movements it is way off on heart rate, way off. With cycling on non-dominant hand (no shifting of gears) and little hand wrist movement it works, but only for this workout. Surge never worked for any. Maybe my arm/wrist veins don't work with Fitbit Pulse technology?

[zalph]

> all wrist based monitors out there have same issue

au contraire -- I've been wearing these 3 monitors during my HIIT: the fitbit Charge HR (wrist), Polar (chest strap), and the LifeTrak (wrist (metal contact, not LED)) (which I got from Walgreens for about $50). 

The Polar and the LifeTrak consistently agree within 1 or 2 bpm; the FitBit consistently reads low after an exercise burst, and reads high after a rest period.  (I.e., the FitBit lags by design).

Drawback of the LifeTrak is that it only reads-out on demand, meaning you have to push and hold a button for ~5 seconds ... really a drag when your HR is at 95%.  (Also, no data is stored, so you can't upload your HR readings for the day ... ... ... oh, wait, that's the same as the FitBit Charge HR, isn't it?)

Moderator Edit: Format

[RobertoME]

Hi everyone and welcome aboard to our Community @zalph. The technology implemented on a wristband trackers is different from other brands or chest straps. When your heart beats, your capillaries expand and contract based on blood volume changes. PurePulse LED lights on your tracker reflect onto the skin to detect blood volume changes and finely tuned algorithms are applied to measure heart rate automatically and continuously.

However there are different factors that might be caused discrepancies on your readings. Typically due to the tracker's fit. For example, wearing your band tightly may constrict blood flow in your wrist and affect the signal. We also recommend experimenting with how high you place the tracker on your wrist. When you're not exercising, wearing the tracker just above the wrist bone--as you would a watch--typically works fine. However, moving the tracker up a couple inches can be helpful during high-intensity exercises or exercises that cause you to bend your wrist frequently.

There are other exercise that due to its nature may present lower numbers, so for this instances the best is to use either the exercise function on the tracker which vary depending of the tracker model. It can be pre-upload default exercise as the Blaze and Surge tracker or by holding for a few seconds the side button of the tracker if we are talking about the Charge HR.

About the information is store on your tracker, all trackers have the ability to store at least 7 days of detailed minute-by-minute data. Summary data (calories, distance, and steps) will be stored for the trailing 30 days. If you wait longer than 7 days before syncing, you may only see the most recent week's detailed data.

See you around and thank you for your feedback.

[zalph]

Here's an experiment that I have repeated a couple of times, now:

On my left (non-dominant) wrist, I wear the fitbit; above the fitbit, I wear the LifeTrak HRM watch.  This forces the fitbit a few inches farther up my wrist (proximal), as recommended during exercise.  I am quite fair-skinned (Nordic), and I have shaved the hair (what little fine, light-colored hair there was) off that small patch of my wrist. No tattoos or moles.

I also wear a chest strap monitor.

With this monitoring setup, I do two different kinds of workout (only one workout per day!): "HIIT cardio" and "steady run".  The cardio workout consists of 10 intervals, each interval is 2 minutes, for a twenty-minute workout.  Each interval consists of 40 seconds of "sprint" (pedaling fast), followed by 80 seconds of recovery.  By the 8th or 9th interval, the sprint segment will bring my HR up to 144, which is 90% of theoretical max (I'm 61yo), and it is in my peak zone. Both the chest strap and the LifeTrak will register this rate (and be within 2 or 3 bpm of each other).  The fitbit will consistently be 10 or more beats behind, claiming 130-134bpm only.  (Not even in the peak zone!)

Workout type 2: I get on a treadmill and run at a steady pace for 20 minutes, fast enough so that my HR gradually rises to 150 bpm (94%) by the 18th minute.  In this case, the LifeTrak and the chest strap still agree with each other, and the fitbit is also much closer to the same reading (144-148, say).

My theory is that FitBit is "smoothing" the curve of my HR during the 20 minute cardio workout by always reporting a running average, maybe over the past 30 seconds or so.  In the cardio workout, which has higher peaks and sudden valleys (recovery from 140-ish down to 125, or so), the fitbit reports low numbers at peak times, because the valleys are being averaged-in.  But during the steady run, where the curve rises gradually and is monotonically non-decreasing (no valleys), the FitBit keeps up much better.

Whatever the actual mechanism, I find the FitBit Charge HR to be unsuitable for tracking my HIIT cardio (sprint and recovery interval) workouts.  When I put myself through that much pain, I'd like some instant feedback to reassure me that it is worth it!  Also, it would be nice if anything like my actual peak zone times could get reported in my daily HR graphs on the fitbit app.  (Long term, I know it's worth exercising, because my resting HR -- according to fitbit and the others -- is as low as 38 bpm (yes, I said 38) minimum, and ~44 bpm typically. (My doctor knows this and says I'm ok, and I'm cleared for High-Intensity exercise.))

[WarrenS]

I have tried several positions on my arm with the Surge.  Initially it tracks fine. About mid exercise, the display goes to two dashes - no reading.  This morning, it came back briefly, then returned to the no reading state for the remaining 10 minutes of exercising.  I was on my Nordic track ski machine today, but see the same thing on the treadmill in the Treadmill mode.  I like the watch but bought it mainly for exercise & heart rate monitor.  I can't tolerate this issue.

[Buckb]

Having had the Surge, and now the Blaze and Charge 2 --- any exercise where you move your arm you can forget about heart rate accuracy. Only time accurate, as checked against chest strap (Garmin), is when cycling with little arm/wrist/hand movement. My research so far for all other devices is the same for wrist measurements compared to chest strap. Have tried all the Fitbit suggestions.

People I have asked about this, seen wearing a Fitbit model, that say it works fine have generally never used a chest strap or compared with one. People who have used chest strap comparison have same issue we have.