Eye Opener

Options
havingitall
havingitall Posts: 3,728 Member
in Fitness and Exercise
I had my eyes opened at the gym today. I had been using the calories burned from the cardio equipment or what MFP says I burned for my workouts

Santa brought me a Polar FT7 heart rate monitor and I wore it today at the gym. 65 minutes on the elliptical is 1145 calories according to MFP and 1225 according to the elliptical. My hrm said it was 646 calories. 30 minutes of swimming according to MFP is 411 calories and my hrm said it was 160 calories. Needless to say, I can understand why my weight loss has stalled out.

I will be adjusting my eating and I'm sure I will start seeing a difference again.

Replies

  • BetterVersion
    BetterVersion Posts: 459
    Options
    Wow. That's quite a difference. I always suspected those numbers were a bit off, but that's dramatic!
  • lenmana
    lenmana Posts: 171
    Options
    Yeah...I keep saying I'm going to buy one. I gave up when I stopped losing and hit my first road block. Now, I've gained back 10 lbs. Think I will go buy one today!
  • phitme
    phitme Posts: 124
    Options
    It is amazing isn't it? Most machines are automatically calibrated for a 200lb man which is why our counts wind up being so wacky. I love my HRM, it motivates me and helps keep me on track. Enjoy your new one.
  • Emilydmo
    Emilydmo Posts: 101
    Options
    I've always been wary about estimated calories burned, so I only ever eat half to 3/4 of my exercise calories, which gives me a little leeway in case they are over-estimated!
  • Azdak
    Azdak Posts: 8,281 Member
    Options
    While some of the numbers you list are obvious overstatements, it is a mistake to react by making the same mistake in the opposite direction--i.e. assuming that the numbers from your HRM are the "gold standard" and that they are always to be trusted over numbers from other sources.

    I think it is important to realize that MFP is not particularly sophisticated in its science. MFPs strengths are in its ease of use, its food database, and its community. The exercise logging part is average to mediocre at best.

    It's sometimes harder for me to relate to the average user on this site since I have an extensive background in exercise physiology so I can intuitively separate good information from bad--or else I have the resources at hand to quickly double check a lot of information.

    HRMs are great tools, just keep in mind that the calorie expenditure numbers are estimates. In some cases they are no more accurate that making a number up out of thin air. They must be set up correctly and the setup data must be regularly updated as your weight, heart rate and fitness levels change. Some of the set up data you enter (e.g. HR max and VO2max) is information you will almost certainly have to estimate or guess at, which brings in an increased error factor.

    HRMs do not directly measure caloric expenditure. That cannot be stated too often. They estimate caloric expenditure based on the known relationship between heart rate and oxygen uptake during steady-state aerobic exercise.

    Steady-state aerobic exercise. That's it. Under any other conditions--rest or daily activities, strength training, combined group classes, an emphasis on upper-body movement, heat stress, illness, high-intensity sprint training that relies primarily on glycolytic metabolism--the heart rate/VO2 relationship is not consistent, and therefore the calorie numbers on the HRM will be off--sometimes by 30%-40%.

    HRMs are great tools if used appropriately, but they are not omniscient nor should they control your program. As far as calories in vs calories out, there will still be a lot of trial and error.
  • havingitall
    havingitall Posts: 3,728 Member
    Options
    Thanks for that info Azdak. I must say that 65 minutes on the elliptical on level 14 did feel like a lot more than that as I had sweat dripping from every pore but I thought that HRMs were the proper way to get the calories burned. Once again I have been educated.

    Nonetheless, I did kick butt with my exercise today. I missed working out Christmas Day and Boxing Day so I wante dto go hard today and it felt great. In addition to not exercising for two days, I ate a lot and needless to say, that demon scale in my bedroom taunted me with the results of the past two days.

Categories