calorie burn bump with altitude?

TheWorstHorse
TheWorstHorse Posts: 185
in Fitness and Exercise
I use a HRM to track my calorie output during cardio. I live at sea level. When I stay at a higher altitude (in my case, 8000ft) and exercise, my monitor says my heart is working harder and, therefore, I am burning more calories than I do at sea level (all other things being equal). This makes sense (at least until I am acclimated to the altitude) but I am suspicious. Seems too easy.

Any exercise physiologists want to educate me? Do I per more calories per unit of exercise at 8000ft than I do at sea level? In other words, can I trust my heart rate monitor (at least as much as I ever do)?

Replies

  • Azdak
    Azdak Posts: 8,281 Member
    I use a HRM to track my calorie output during cardio. I live at sea level. When I stay at a higher altitude (in my case, 8000ft) and exercise, my monitor says my heart is working harder and, therefore, I am burning more calories than I do at sea level (all other things being equal). This makes sense (at least until I am acclimated to the altitude) but I am suspicious. Seems too easy.

    Any exercise physiologists want to educate me? Do I per more calories per unit of exercise at 8000ft than I do at sea level? In other words, can I trust my heart rate monitor (at least as much as I ever do)?

    You are assuming that an HRM is a calorie counter, which is always a mistake. An HRM measures heart rate.

    Period.

    It then uses to HR to estimate calories. The prediction equations that are used by HRMs to estimate calories are only valid (and accurate) under very limited conditions.

    Altitude training is not one of them.

    HRMs are programmed to reflexively display a calorie number based on the heart rate impulses received from the chest strap. The HRM cannot interpret the source of those impulses, nor the conditions under which they are generated. Since an HRM has no brain, it depends solely on the brain of the user, to interpret the numbers correctly and to know when the HRM is producing nonsense.

    At least during exercise, you will almost always burn fewer calories at altitude, not more. That is because the altitude limits how hard you can work. For example, someone who can run a 7 minute mile at sea level might only be able to run 9 min miles at 9000 feet. Even though HR is higher, the person is burning fewer calories because they are running slower. Calorie burn on the HR M will be higher because the heart rate is beating faster due to the increased need for ventilation at higher altitudes. But that number is not correct
  • TheWorstHorse
    TheWorstHorse Posts: 185
    EDITED to account for interwebs research.

    Spent an hour looking at articles; couldn't find any published research. The consensus is: calorie burn rates do not significantly change with altitude, even if perceived exertion does. Any effect will disappear as one acclimates (two to six weeks). Using the HRM estimate might be wrong (I am going to track this for a couple of weeks and see) but not by a great deal. Using historical data for the same exercise done at sea level should work okay.

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