Smart watch: Hi, does anybody wear a... - British Heart Fou...

British Heart Foundation

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Smart watch


Hi, does anybody wear a smart watch to monitor their heart rate? How accurate are they? Do they make you paranoid and look for problems?

35 Replies

I've got one and to be honest as a device for measuring your heart rate it's not that good. I've checked it against my Omron blood pressure machine and while the Omron will show my heart rate at 58 (which is where it normally is) my watch shows 75. I tried it a number of times and while the figures change a bit the watch is consistently much higher. The Omron is only about 9 months old and I've had it checked for accuracy, so it's definitely the watch that is out. That said I find the watch useful for recording my steps/activity and number of calories burnt, and it's measurement of my sleep quality, so I find that it has it's uses, it's just that measuring my heart rate isn't one of them.

Thankyou for that, I have one but It keeps telling me my hr dropped well below 40, I was curious as to the accuracy so thankyou

The thing to do is to manually check it. If you are a runner your heart rate may regularly be around 40. If not it would be worth a chat with your GP.

Trog1 in reply to sprocket00

If it’s any help, I find my Fitbit has recently shown a resting heart rate of around 42 to 44. I must admit it caused me to worry and I was watching it more often as my resting heart rate is generally between 49 and 55 so wondered what was wrong to change it. However, I contacted my GP who says not to worry as I am on a low dose beta blocker which may lower the rate a little now and again and that unless I am feeling faint or pass out it is nothing to be too concerned about.

My Honor Magicwatch 2 is surprisingly accurate IF I wear it a little tighter than comfortable.

If I wear it comfortably then it works really well during sleep and during exercise (always within a beat or two of my Polar chest strap which is the gold standard during workouts) but goes a little random at times through the day - usually reading high rather than low.

Hi, thankyou I have the same but I find during the day my heart rate will randomly drop very low and then come back up all in a space of a few minutes, otherwise it seems accurate when compared to hospital equipment.

Hi, I’ve started to wear a heart rate watch. I had a triple bypass 12weeks ago and felt it was sensible to keep any eye on it, plus you do need to know your maximum heart rate for your own condition which you can set on these watches. In my experience I think you would find wearing a heart rate chest strap to give you a pretty accurate result on your heart rate. Mine pairs up to the watch and records all the info on my phone app.I’ve found generally just using a watch, Fitbit etc your not going to get a accurate reading as wearing a strap.

I’ve been using a polar chest strap with watch and I’m pretty happy with it. I know it all depends on budget but long term I think of it as a bit of an investment.

Good luck.

i’ve had a fitbit charge 3 for about 18 months and to be honest it’s been pretty accurate.. my HR especially in the evening falls into low 50’s to low 40’s.. a few times i’ve checked it by taking my pulse manually and using bp monitor.. and 9 times out of 10 futbit has been correct

Hiya Sprocket I hope you are keeping well. I bought an Apple Watch just prior to bypass surgery. I’m now 12 weeks post op and have found the watch to be a great comfort. Yes you have to stop yourself becoming obsessed with all the potential measurements, but it has excellent heart monitoring, sleep management and fitness programmes that encourage you to be well. I wear it to bed at night and it’s fantastic to see how your heart has preformed during sleep the next day. It also has an ECG function that detects any signs of arterial fibrillation.

I don’t know if they are 100% accurate, but I’d say as good as most and a lot better than others.

Hope this helps and Be well, Terry

Lizbeth61 in reply to Telboi

Another vote for the Apple Watch. I have to say I love mine too for all the reasons you mention above

Bug146 in reply to Lizbeth61

And me

Gaz_chops in reply to Telboi

When I did my re-hab I was told that they had tested a number of watches and that the Apple Watch was the only one that was accurate enough for them to accept the readings during re-hab sessions, instead of the polar chest strap.I have checked mine many times against hospital equipment and finger on wrist and it has been spot on every time.

The only thing I would say is that you have to make sure that you wear it snug on your wrist, especially during rigorous exercise.

I have had a Withings Steel Hr for several years. It’s spot on when checked against the hospital equipment. The advice I was given when exercising is not to rely on it for level of exertion, ie don’t stop exercising necessarily if HR reads high but rather if you feel breathless/tired etc.

My Fitbit Blaze is bang on with my BP monitor, give or take plus or minis a beat or two

Wouldn’t be without my Apple Watch it’s a godsend as accurate as anything else

Hi there

I would say treat any readings from a smart watch with caution, from my personal experience.

I use a Huawei smart watch paired to my phone and it regular records my heart rate as far higher, especially when cycling. This is compared to wearing a heart rate strap paired to my Garmin cycle computer which is a lot more accurate.

As others have said though, a lot is dictated by your budget and what ever equipment you use, you can still use it to observe trends & patterns.

Hope that helps?


I use a Garmin Forernner 45 - but I have it for tracking runs. The rate monitoring on it is pretty good, despite me being in permanent afib. Because it is not a smartwatch, the battery lasts a week between charges. I occasionally have a look at my heart rate during the day out of curiosity, but it is easy to become obsessed with checking it at first. Now I don't treat it as gospel - I compare my exercise rates and resting rates for the difference, not the absolute value.

What do you really want a smartwatch for ? If you actually want a heart rate monitor, base your choice solely on that. If you want the smartwatch functionality, choose that. If, like me, you just want to keep an eye on your rate but really want a good exercise tracker, go Garmin or Fitbit.

(I did have a Samsung Galaxy Watch Active, but when I switched from Android to an Iphone the battery life went down to hours. It was quite accurate for heart rate though before that, and quite a good smartwatch.)

I have an Apple Watch and find it very accurate. It really gives me peace of mind if I feel my hearts playing up. It definitely doesn’t make me paranoid at all. I only check if I feel my heartbeat is a little fast or having ectopics etc.

Angel150 in reply to LMor

Me too love it!

I did but it made me so paranoid my anxiety went through the roof, so I’ve sold every one I’ve had. Accurate? Is say within 5-10 beats with abit of a delay, also hears the red laser ones are better or more accurate than green laser, I swear I read that somewhere, I may be wrong

Look at the Withings scan watch, very smart, hybrid watch. I tried a Samsung galaxy watch 3, but charging daily was painful. Battery lasts 20-30 days, has Sp02, ECG, respiratory scans, Afib alerts, monitors most sports, heart rate and a great app.

Just thought I would add my two pennyworth. I use a Garmin Instinct watch, that prior to my AVR, I only used really to track my cycling and hillwalking. Since my AVR, after the first couple of weeks I started to wear it all the time. I wear mine with the watch face in the inside of my wrist, as I find this generally seems to give a more accurate reading. If you want a truly accurate heart reading, then you would need to use a compatible chest strap with it. I can’t imagine anyone would want to wear a chest strap 24/7 though. As other commenters have said, it doesn’t matter what make or model you use, they are all prone to inaccuracy. At times I got readings that seemed either far too low, or far too high. Initially this began to worry me, then I realised that on these occasions all I had to do was check my wrist heart rate manually. Problem solved, it was always the watch that was giving a false reading. In the last year, I would estimate I have only had an obvious false reading on a few occasions. You also need to be aware that there is often a slight delay before the watch adjusts to a new reading. I find it very useful to help monitor my general health and fitness. In particular identifying when I am possibly tired and need to rest, and also for keeping an eye on my heart rate at different levels of exertion. I did wonder if it would make me more paranoid, but in my own case it hasn’t, I have just found it as a very useful aid in my recovery.

I have a Fitbit Charge 3 and I would say it is as accurate as the Omron bp machine.

Wrist based heart monitor functions l believe generally work on detecting changes is skin pallour.So as the heart pumps and infuses the skin, it pinks up and colour changes detected.

Chest strap monitors measure actual electrical variations as the heart beats, so offer greater accuracy.

Both are useful for training or monitoring activity and fitness. When I was in post-AVR rehab, I used a Suunto watch to keep an eye on heart rate, under exertion, and also for feedback on improving cardiovascular capacity.

I now use a chest strap with cycle computer and phone.

Just as an aside, the free download version of Strava training app now allows heart rate recording, albeit using a Bluetooth enabled chest strap which can be bought for around £30 from Decathlon and Halfords. May work with a watch / Fitbit too, but I've no experience of that.

I wear Polar chest strap when I do exercising and I found it very accurate, you need a smart phone to collect , store and view the live data, all wrist monitors use a technology to check the changes in the skin colour and hence they are not as reliable , couple years ago they were tested on the "BBC 2 trust me I am Doctor" and more or less they came with the same conclusion! Hope it helps!

I have an Apple watch and find it very good. It recorded an episode or two of AF leading me to get it looked at. I also suffer from apoxia and it measures that too, keeping graphs of readings. I love mine - have just upgraded to Apple Watch 6 from 4 that did AF but no 02 measurements.

Hi - other than in the early days of returning to cycling I did not see the point of continuous monitoring of HR. I wore chest monitor when cycling for a while so I learned what it felt to ride or exercise at a reasonable maximum HR for my age etc. but thereafter relied on my perception of effort and comfort. I think we are all aware of what our hearts are doing at any given time e.g. too slow/too fast, but anything in between is surely not worth continuously watching. I may well be missing something given the investment in smart watches - but more than happy to be told what it is :)

The original is the Omron HeartGuide £499 here and $499 in

Hi Sprocket. I've got a Polar watch which seems to be fairly accurate. I wear it in the gym (which I haven't been to for 9 months!) in conjunction with the chest strap, and the gym equipment (at least Technogym) will read it.It was recommended after my HA when I went to Cardiac Rehab 2 years ago, and for the first few months I wore it all the time and was always checking it, but to be honest, the novelty wears off and I generally now only wear it if I'm planning a decent walk or bike ride - and then I forget it half the time!

hi hope you're keeping well, i used a smart watch fitbit just after quadruple bypass to gauge how i was going distance/heart rate etc to find a pattern that fitted what i had been asked by the heart team to try and work towards and also fitted into my new lifestyle and kept using it until i found a level that suits my body (as a minimum daily routine) and after that i stopped using the fitbit and tend more to make sure i’m doing the basics but listen to my body more and on the days when my body says we’ll do a bit more we do it and some days it tells me the basics enough for today. its similar to the levels of certain meds some need more and some less, hope you find your own health level soon.

I developed a sudden interest in heart rate after my double bypass last year :-) My wife bought me a basic Garmin Vivosmart, but I soon discovered that that was not accurate in the cardio physio sessions, comparing it with the chest strap and watch provided by the physios. I now have a Fenix 5 that was a birthday present. However, to be honest I only really take note of heart rate during exercise, when I use a chest strap because it's more accurate than a wrist-based sensor. I do use the watches to keep a general track on steps and exercise and so on, but at present I'm mostly using Zwift, where a watch is not that important because the strap links directly to the device running the Zwift programme.

Hi. I have apple watch 6 and its shows perfect when you are sitting. I had checked with my pulse oximeter, blood pressure monitor other watch and phone heart app and its shows +- same. But when i move.. no no its showing bad. And SpO2 in apple watch doesnt work properly or mine is defective 🙄 i bought apple watch for all this functions ECG, heart rate, spO2 but its doesnt worth that money!

There is no smart watch with hr or ecg function etc. rated as appropriate for those with pre-existing cardiac problems. That’s not to say they don’t work for people with a diagnosis, just that Apple, Garmin et al. acknowledge there’s sufficient variability and possible inaccuracy that they would open themselves up to lawsuits if they said otherwise, and so state not suitable for those with a pre-existing heart problem in all the literature. Do a quick google and you will also find numerous scientific studies that show many consumer fitness/hr monitors including fitbit and garmin can be out by as much as 20%, meaning they’re not always giving you the accurate data you paid for. The most reliable home method of checking hr during activity (other than manually taking your pulse) would be a device utilising a chest strap as others have suggested, and from when I was looking last year, these tend to come in at a lower price point than many decent smart watches or wrist worn devices. If you just want something to occasionally spot check your rate, you’d be just as well off spending £30 on a decent fingertip SpO2 monitor.

I think it depends on your personality as to whether it makes you paranoid or not. I agree with the others use it for activity, sleep etc and not heart rate.

Ive got one called Veryfit and the Veryfit app its connected to. It shows and stores heartrate, any activities, sleep pattern. Mine was normally pretty accurate until Thursday just gone. I was on the treadmill doing a stress exercise test at the hospital and they were pushing for target heart rate of 188 and the watch said 79!! Sometimes accurate, i find its better when worn tighter.

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