Apparently stairmaster at 12 METs for 3 hours and avg 100HR burns under 100 calories

Former Member
Former Member
I'm getting seriously frustrated with the severe inaccuracy of my fenix 5.

Today I did a 3 hour stairmaster session (I regularly do 3-5 hours) in which the machine read 1228 floors and ~2500 calories burned. I am a male, 34 years old at 6% body fat 145lbs

With garmin soft HR strap, at 12 METs for most of the workout, my heart rate was an average of 100.

I would describe this as an intense workout, it would have been hard to talk to someone during the workout. I was drenched in sweat after.

This workout registered 93 active calories! And the steps were definitely being counted. But sometimes 5 or 10 minutes would go by, in which the active calories increase by like 1 or 2!

What is mind-boggling to me, is that if I walk for an hour at a slow pace with heart rate around 70 or 80, I will burn more calories! Like maybe 250 an hour.

I am aware the garmin can't see the "vertical ascent" since I am on stairmaster, not a real stairs, but it does see the heart rate, and it does see the steps..... but walking at a slower pace and lower heart rate burns more calories....

Has anyone else experienced this? It is just very frustrating. Should there be a way to enter the "METs" into an activity to give the watch more data about what is occuring?

If you goto this site http://lamb.cc/calories-burned-calculator/

and enter 145LBs, 3 hour workout at 12 METs, you will see the calories are close to 2500... but garmin shows less than 100. This is embarrassingly inaccurate. I am aware the stairmaster could potentially be high slightly, but I burned at least 1500 during this workout..

Any idea what is going on here?

This article makes me think its the METs that count here... not the heart rate:

https://www.myfitnesspal.com/blog/Azdak/view/calories-burned-during-exercise-it-s-the-intensity-not-the-heart-rate-that-counts-26524

Is this accurate? Can garmin add a feature to enter the "METs" during an activity to increase accurate if such a feature doesn't exist?
  • Former Member
    0 Former Member over 6 years ago
    I am a male, 34 years old at 6% body fat 145lbs

    With garmin soft HR strap, at 12 METs for most of the workout, my heart rate was an average of 100.

    I would describe this as an intense workout, it would have been hard to talk to someone during the workout.


    Not to drift off topic, but I'm a little confused about the numbers you posted. Even if you use the outdated formula of 220 - age, your Max HR is 186. Do you really find a workout averaging a HR of 100 intense? This would almost put you at 54% of your Max HR. I can't see how that would make it hard to talk with someone and how you'd be drenched in sweat unless you had the heat set to high. Are those numbers correct?
  • Former Member
    0 Former Member over 6 years ago
    I think it's possible the HR data is wrong, even with the strap. My max HR is also closer to 175. I just walked my dog for 20 minutes with an avg HR of 70 (zero effort whatsoever) and evidently burned more calories than 3 hours on the stairs in just 20 mins walking.

    The fenix 5, for whatever reason, counts *zero effort* walking as much more calories than intense stairmaster session.

    The stairmaster was def intense, and I don't think the METs lie... 12 METs is a lot of effort.

    From what I have been reading METs are the better way to calculate burn than HR... during this stair session I was breathing very heavily. Sweating like crazy and it was cold in the gym too.

    Something doesn't line up
  • Former Member
    0 Former Member over 6 years ago
    My max HR is also closer to 175.


    I can't explain the issue you're having with calories burned, but I think you may want to look into your max HR a little further. I'm 20 yrs your senior, wish I had 6% body fat and for my age I consider myself a little higher than average with my fitness level. My max HR is only one below yours. What did you do to determine yours? If you're doing 3-5 hour workouts on a stairmaster I would suspect yours is set too low.
  • Former Member
    0 Former Member over 6 years ago
    TMK17 thanks for feedback. If I go my absolute hardest on the stairmaster (level 20 which is max, double stepping for 10 mins), my HR never goes above 175. I have been told the reason my max HR is so low is actually a sign of good conditioning. Not to sound cocky, but I think it's possible I have climbed more floors than anyone else in the world in the last year lol. I regularly do 1500 floors per day. So maybe my body is just used to the machine, But I don't think that is the case b/c I know I'm working hard during these workouts. I don't have an answer. But here me on this logic:

    Climbing a mile should automatically be more calories than walking a mile at a 0 incline. The machine I was using today doesn't track miles climbed, but the one I own does. And the machine itself reports about 110 calories for each mile climbed (using no HR data, just weight). Seems reasonable. I definitely climbed over 15 miles today, so this workout should have been at least 1500 calories burned in my opinion.

  • Try using the generic Cardio activity and record heart rate only, and make sure you don't have any sensors connected. Note that calories used is indeed calculated from heart rate, so if your heart rate is really low you will use less calories, which is why the more fit you are and the less you weigh, you will lose less calories when working out.
  • I agree with the suggestion of using the generic cardio activity with no sensors other than HR.

    And maxHR is basically a factor of genetics and age - fitness levels do not impact maxHR (resting heart rate however is a good reflection of fitness).
  • Maybe it’s a faulty strap, or positioning of it? Sounds like you’re working hard. 100 bpm would be below the L1 range based on a max of 175. Sounds like your perceived effort is much higher than Zone 1 /warmup. So I think the HR reading is incorrect.
  • Former Member
    0 Former Member over 6 years ago
    100 bpm would be below the L1 range based on a max of 175.


    This is exactly what stood out to me. Even with a Max HR of 175, the OP shouldn't find it difficult to talk or be drenched in sweat when averaging a HR of 100 and felt the workout was intense. Not to raise any unnecessary red flags, but hopefully it's not a medical issue. I did notice the OP started another thread about his strap continuously disconnecting, and this would obviously explain the low HR and calorie readings.
  • Former Member
    0 Former Member over 6 years ago
    Yeah something is totally out of whack with the heart rate. The WATTS here is over 275 -- this is a lot of effort..

    Regarding the wrist heart rate, something is totally messed up... if I slowly walk up an actual stairwell, very little / slow effort, it shows my heart rate around 120-130 most of the time. I feel like Garmin is "lying" about the HR and increases it just b/c it sees a vertical ascent.. how can it be explained that climbing an actual stairs extremely slowly makes my HR higher than a brutally intense workout on stairmaster machine? Can a programmer at Garmin comment if the HR is artificially increased / guessed just b/c the watch sees a vertical ascent?
  • What the are METS and why do you treat them like the holy cow?