Silly question re: HR and calories burned, going over 85%HR

kspeach
kspeach Posts: 179 Member
edited September 21 in Fitness and Exercise
I'm such a dork, and at the moment, I'm brain dead.

I'm working on C25K and am on Week 4, day 3. I had been training on the treadmill, but took it to the beautiful outdoors today, and have a 5K run walk on the 16th.

Anyway, this is a question about HR and calories burned. I use a very good and reliable HRM by Polar. It's been very accurate and I believe it to be accurate now. My question is,do I not burn as many calories when I go over my calculated max of 152 (85% of my max HR)?

My stats for my C25K training portion today, and then those for my walk afterwards; I timed the walk to match up with the run time.

C25K: 21.5 minutes, calories burned 208, HR: Avg: 151, High 164, in zone (65%-85%)only 11 minutes :(

Walk post C25K: 21.5m, calories burned 190, HR: Avg 143, High 160, in zone 20 minutes.

So I'm not burning any calories hardly at all when I go over 85%? Is it similar to when you're under your 65% and you aren't burning as many calories?? I just want to make sure I understand this right....I tried to slow down, but it felt like I couldn't go any slower and not be going backwards! LOL

In case you want to know, I burned 181 on my C25K Week 4 on Monday, on the treadmill, with 144/157 HR avg and max.

Thanks in advance y'all! :)

Replies

  • Azdak
    Azdak Posts: 8,281 Member
    The biggest problem with HRMs is that they estimate calories indirectly by making assumptions about HR and oxygen uptake. They also make assumptions about your max HR as well.

    Any variation from these assumptions will throw off your calorie count.

    In your case, for whatever reason, your heart rate does not seem to recover very fast after exercise. Since the HRM only measures heart rate, all it knows is that there wasn't much difference in average HR between your run (avg 151) and your walk (avg 143). Again, since the HRM is only looking at heart rate, it assumes the difference in effort was very small.

    I am assuming there was a noticeable (significant?) difference between your running speed and your walking speed. If so, then it's just that your HR doesn't seem to recover very fast after aerobic exercise (or it didn't after THIS particular exercise workout). Why that is I wouldn't even hazard a guess.

    In any case, it has nothing to do with calorie burn. The recovery numbers only reflect your elevated post-exercise heart rate, not the actual calories burned.
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