Weight lifting and heart rate moniters

dwiebe85
dwiebe85 Posts: 123
in Fitness and Exercise
Can anyone explain to me why you can't use them for weight lifting? I know that the calorie burn is greater after the session, but can I still log my calories from what the HRM says I burned? Or is that innacurate?

Replies

  • Spanaval
    Spanaval Posts: 1,200 Member
    Weight lifting utilizes the anaerobic pathway. HRMs are meant to measure the results from cardio (as an indirect measure of VO2), which utilizes the aerobic pathway. If you do use HRM to estimate your calorie burn, it will be off.
  • wellbert
    wellbert Posts: 3,924 Member
    the math thinks you are doing cardio. overestimates a lot.
  • dwiebe85
    dwiebe85 Posts: 123
    So even if it says 150 calories I shouldn't log that, even though most of the burn cames later? Do I just not log anything?
  • shorty35565
    shorty35565 Posts: 1,425 Member
    U can log whatever the HRM says, but don't take it seriously. I use my HRM when I lift so I'll have something to log, but I dont take them seriously. If you don't eat back your exercise cals, which I don't, then it doesn't really matter.
  • waldo56
    waldo56 Posts: 1,861 Member
    Strength training burns a ton of calories. HRM's miss very low because they don't account for the anaerobic energy burn. Plus they don't account for the calorie cost of muscle repair, which is very significant (about a 20-25% rise in your maintenance calories while recovering (2-3 days)). This assumes of course that you actually lift enough weight and work hard enough to damage your muscles.
  • MarcusModulus
    MarcusModulus Posts: 2
    "A number of recent studies suggest that vigorous weight lifting exercise may elevate calorie burning above usual resting values for several hours after exercise. However, the average person at the gym who rests for several minutes between sets of exercise will likely not experience a prolonged elevation of postexercise energy expenditure....
    "Some fitness enthusiasts have promoted the idea that because regular weight lifting can increase skeletal muscle mass, such exercise will dramatically increase RMR. However, it is estimated that each pound of muscle burns about five-10 calories per day while at rest, so you would have to bulk up quite a bit to increase your RMR. Most people who lift weights for health rather than for body building will not increase their muscle mass enough to have a major effect on RMR."
    - source: http://sportsmedicine.about.com/od/anatomyandphysiology/a/rmr_2.htm

    So it may have some effect but don't go crazy about it. I just use the "weight lifting" exercise in the exercise database to log it. If your really looking to go for the lowest estimate and you do put a moderate effort in (you wait about 30 seconds between each lift), I would simply use the walking exercise. I assure you that you burn more with moderate-to-vigorous exercise weight lifting than you do walking.
  • dwiebe85
    dwiebe85 Posts: 123
    So could I log like 150 calories?
  • Jynus
    Jynus Posts: 519 Member
    the math thinks you are doing cardio. overestimates a lot.
    depends on intensity. Once you're able to push a lot of weight and do actual strength training (ATP-CP pathways as primary muscle power source) the calorie burn is utterly destroys cardio. There is a reason elite powerlifters eat 10k calories a day.
  • Jynus
    Jynus Posts: 519 Member
    Can anyone explain to me why you can't use them for weight lifting? I know that the calorie burn is greater after the session, but can I still log my calories from what the HRM says I burned? Or is that innacurate?
    you can use them for low impact weights. So anything >20 reps would be pretty accurate as you're basically doing cardio at that point and not resistance training.

    But the reason they are inaccurate otherwise is because of how the body works. You have 4 energy systems that power the muscles. fatty acid, cardio, lactic acid and ATP-CP. The first 2 use oxygen and glucose/fat in your body to make ATP to power the muscles. As oxygen is part of the equation and is constant, and your heart rate correspond to oxygen used by the body quite accurately, you can make an educated guess as to how many calories you're actively burning. (within an upper range of 30% inaccurate)

    However, lactic acid and ATP-CP do NOT use oxygen to make ATP to power the muscles. So heart rate monitors don't have a clue as to your calorie burn from weights as it's basically using glucose straight from the muscle, and replenishing it straight from the stomach/fat stores with no oxygen needed. And at upper levels of strength, the calorie burn is utterly off the charts. As I mentioned earlier, once you can start pushing some serious weight, strength training just obliterates cardio in terms of calorie burn. though a HRM would read it as a fraction of that.
  • dwiebe85
    dwiebe85 Posts: 123
    So I should be safe then just logging 150cal?
  • KaleidoscopeEyes1056
    KaleidoscopeEyes1056 Posts: 2,996 Member
    So I should be safe then just logging 150cal?

    No, only if it's 151 calories.
  • rvagnoni
    rvagnoni Posts: 75 Member
    bump
  • waldo56
    waldo56 Posts: 1,861 Member
    And at upper levels of strength, the calorie burn is utterly off the charts. As I mentioned earlier, once you can start pushing some serious weight, strength training just obliterates cardio in terms of calorie burn. though a HRM would read it as a fraction of that.

    Yes.

    Try lifting heavy and eating to gain weight.

    MFP's #'s are LOL low. A fraction of what they really should be. For me, when I take into account the elevated calorie burn for 2 days of recovery, strength training burns 1500-2000 calories per session (1-1.5 hours).

    Heck I eat >3500 calories per day and I'm simply maintaining right now, not eating enough to gain. (@6'1", 190)

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