Calories burnt, WHen not in user

magadre Registered Users Posts: 1
New Traveler
edited January 24 in TomTom Sports
The watch shows calories burned even if I was not using it.
I had removed the watch while sleeping and when put it on again when i woke up andh checked the calories already it was showing calories burnt ?
Also the HR Monitoring is weird. When the heart should be 140+ the watch shows much lesser and sometimes weird figure like 76, 90 etc.
I have crossed checked this with strava and chest heart rate monitor.
I think I blew up my money on this product.


  • xray79
    xray79 Registered Users Posts: 160
    Renowned Wayfarer
    The calories are counted throughout the day. Even as you sleep you will 'burn' calories. Average is calculated based on your profile.
    When you wear the watch and do an excercise the calorie consumption will be higher compared to non excercise days.
    The HR is optical and can be off due to various reasons. When you do weightlifting/cross-fit the HR can be lower due to the fact that you compress the vessels a bit more. This is a known issue for all optical HR devices as you will hold something in your hand or press down wen you do a bike ride and that compresses the vessels in your wrist. When you run/walk etc. this is less of an issue. Another reason can be the cold as that also compresses the vessels..... A good warm up or trying another arm might help. If you do a search here you will find more solutions to this issue.
  • tfarabaugh
    tfarabaugh Posts: 16,943
    If you were alive and breathing, digesting, etc. then you were burning calories and that is what a 24/7 activity tracker is supposed to be tracking. It computes a BMR based on your gender, height, weight, etc. and takes this along with steps and sports activities to come up with calories burned. So between midnight and whenever you woke up you burned 400 calories just being alive. This is exactly what it and all other activity trackers are designed to do. In my experience it is generally pretty accurate (or as accurate as BMR based calculations can be as they are based on averages).

    What activities are you doing when you see the heart rate fluctuations? There are two issues around heart rate using optical HR monitors, and these are on all devices, not just TT ones: low heart rate and HR spikes. Low HR is often seen in rowing, cycling and weight lifting. Any time you do an activity that squeezes or tenses the forearms (like the pull stroke in rowing, bearing down on your handlebars in cycling, or virtually any weight lifting move) you are squeezing the blood vessels the watch is reading, so it sees this as a reduced pulse. It is not that the watch is having a problem reading your pulse; it is that your pulse at the wrist has actually dropped because you are temporarily cutting off blood flow to the vessels it is reading. I have experienced this with every optical HR I have used, including a Mio and a Scosche unit. For these sorts of activities you are better off using a chest strap synced to the watch if getting a more exact reading is important to you. Based on numerous tests I have performed, I find that with weight training it is generally 5%-7% lower based on the wrist than the chest, so if I do not use the strap I just adjust accordingly.

    Spikes in HR are generally from poor blood flow producing weak pulse strength, so the watch reads cadence instead. This is most common in running and is particularly apparent early in a workout or during a non-intense workout when you are not warmed up. You have to think of the optical heart rate as an algorithm that is attempting to track a signal in a set frequency range (30-230 or whatever it uses). If the pulse signal is weak it latches onto the next strongest rhythmic signal, which is your cadence in running and the vibrations of the bike in cycling. For most people who experience this while running it spikes to around 180-200 bpm which is also the average cadence people run at. Additionally, each person has a different HR signal ‘strength’, depending on a range of factors, so some are prone to get it more than others. But usually their signal strength is lower for the first 5-10 minutes until they warm up properly. So in that time, it is prone to latching onto cadence, which is a common fault with all optical HRs, unfortunately. If you notice it while it happening you can try moving the watch a bit or briefly pausing your run so it loses the cadence reading and latches back onto HR, which I find usually corrects it. I generally pause the watch, stand still for 20-30 seconds and will see it immediately start to drop. Once it gets into a more reasonable range and the pulse reading stops dithering (dithering is when it is not getting a good signal and it is a lighter grey in color) I start up again and it stays true for the rest of the run. You can also try switching wrists and the position on the wrist. I find I got better readings on my right wrist over my left and some people find they get better readings if the watch is on the inside of the wrist rather than the outside. It also helps if you warm up a bit to get your blood moving and your HR up so it is producing a strong signal. Play around with it and see if any of this helps you. The challenge for the manufacturers of optical HRs (and this is a common issue with all brands, my Scosche also does it) is to figure out how to factor out the other "noise" that is overriding the pulse signal without also factoring out other important data.

    I hope this helped answer your question. If so, please mark it as a solution so others can look for it if they have the same question.