How precise is the apple watch with stationary biking calorie burn

Discussion in 'Apple Watch' started by Drecca, Aug 3, 2016.

  1. Drecca macrumors regular

    Aug 30, 2010
    Since it's stationary, the only thing the watch has to go off of is the heartbeat. How precise is the calorie burn measurement when doing stationary biking? Has anyone ever tested it?

    I usually do what i'd call moderate exercise, so enough that i can have a conversation, but still sweating and breathing.

    The watch reads a range from anywhere between 450 to 700 calories per hour burn. Since I do this about 4-5 hours per day, it's a really big range.

    To compare, I do a 7km walk at around 5.8-6.2 km per hour, and the watch says I burned around 350-380 calories during the entire walk. So that range is much narrower... just really questioning the stationary biking one...
  2. Mlrollin91 macrumors G5


    Nov 20, 2008
    Ventura County
    I use a stationary bike every day with my Apple Watch. Been doing this for over a year now. On average I burn 10 calories a minute with an average heart rate of 145BMP. I am fairly consistent. I do a 30 minute cycle everyday and I always burn between 280-320 active calories. Its more than just heart rate that is taken into consideration, there is an algorithm that the watch uses to determine calorie burn and then the heart rate is added on top of that. If my heart rate is not being read, I get about 4 active calories per minute of cycling. So typically the heart rate adds roughly 6 active calories per minute. Obviously that is dependent on what my heart rate is.

    On average, with outdoor walks, I burn about 4 active calories per minute with an average heart rate of 120BPM. Obviously this is less intensive than indoor cycling, so the algorithm has a lower active calorie burn rate, and then heart rate is added on top of that as well.
  3. exxxviii macrumors 65816


    May 20, 2015
    Back in the first part of the year, I was wearing my AW while doing indoor rides 4-5 times per week. I had a power meter on the trainer, and I also had a Garmin 910XT. The AW would give consistently very low calorie calculations compared to the other two, and given that the trainer had power and aligned more with the Garmin, I distrusted the AW's calorie readings on the bike. The AW lost on a 2-1 vote. For example one of the last I compared was 90 minute indoor ride: the Garmin calculated 1,431 calories, the trainer calculated 1,296 calories, and the AW calculated 718 calories. The level of effort of that ride was consistent with outdoor runs with similar calorie/minute burn as the Garmin and trainer were reading.

    However, the AW might be getting better through one of the OS updates...

    I mostly quit wearing my AW while riding indoor, because of the accuracy gaps. However, I just looked up a ride I did on July 13 where I had a power meter on the bike with my Garmin Edge 520, the same power meter on the trainer as before, and the AW together. It was a 71 minute workout. The AW calculated 788 total calories, the Garmin Edge 920 calories, and the trainer calculated 1,219 calories. So that time, the trainer was the outlier. Though the AW was still low, and the underestimation of the AW is consistent with other indoor actives it estimates.

    I am planning another ride tonight, so I will try to remember to wear the AW and do another 3-way comparison.

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