Crazy calorie burns for P90X? Can this be right?

rides4sanity

My hr and cal burns are always higher than I think they should be. For instance I can teach a spin class and talk the whole time with an average hr in the 160's max'ing in the 190's. According to the charts this shouldn't happen in your late 30's, but it does and I'm perfectly fine. Because the calorie burn is based primarily on hr, I feel is not completely accurate for me. Because of this I tend to only eat back about 60% of the calories I record. Heart rates and such are based on an average, and its possible you are just a bit outside of that. You can easily verify your HR monitor by doing a 15 second pulse count and multiplying by 4, if the monitor is good but you are higher than you think you should be talk with your doc just to make sure things are good. Otherwise keep on busting out the workouts, good luck!

heybales

I've been using my HRM during P90X for a couple weeks now, and from what I've read on here, I'm burning a lot more calories than average.... or my HRM is reporting high. I have a brand new Polar FT4. I'm 6'1", 174 pounds, 34 years old, and before P90X I was nearly completely sedentary... my exercise mainly consisted of carrying around a 20 pound baby, and a 0.7 mile walk between the train station and work (desk job).

For example, last night I did legs and back and ab ripper X, and my HRM said 1085 calories burnt. My average heart rate was 137, max was 173, and time in zone 1:06:03. I push pretty hard in these exercises, and the pull ups always get my heart rate up there (I'm sure that's where I hit 173).

But... really, 1085?

For comparison, doing C25K Week 2 Run 1 the other day (walking @4mph, running @6mph, 1% grade on the treadmill), I burned 385 calories in 30 minutes, according to my HRM. (average HR 137, max 165, Time in zone: 18:23)

Does this sound right to anyone else?

The HRM calorie calc's are only accurate for aerobic type activities - a lot of that is like weight lifting - anaerobic.

So while the HR is getting up there because of the effort involved, it is anaerobic and therefore very inaccurate estimates.
Because it thinks you are hitting those highs aerobically, which would be massive burn then.

That being said for calorie burn estimate during the workout - if you include the fact anaerobic burns much more after the workout for hours with increased metabolism and repair/recovery of muscles - in total, that is probably closer to the truth.

If you are wanting to know in an effort to feed your workout correctly so you'll benefit from it fully, I'd say go for P90X estimate of burn, because you'll soon reach that as you get more aerobically fit, and if you start seeing difficulty with workout, like your body is just not recovering enough, then eat them all back.

KissesHugs2

I am interested to know the same thing. I also do P90X sometimes and also Zumba. I purchase a Sportline SX HRM a few weeks ago and it told me that I burned 835 calories for an hour and 15 minutes of Zumba. My maximum heart rate was 206. It was a hard workout but I am not sure what to compare these numbers too ???

heybales

I am interested to know the same thing. I also do P90X sometimes and also Zumba. I purchase a Sportline SX HRM a few weeks ago and it told me that I burned 835 calories for an hour and 15 minutes of Zumba. My maximum heart rate was 206. It was a hard workout but I am not sure what to compare these numbers too ???

It's really not a matter of what your max was, because that could have been reached 1 time for 2 seconds, and your avg was actually 120.

That's what is closer to fact, your AHR.

And there are a bunch of responses in this thread mentioning what you can compare it to or the recommendation - not sure if you read them or not.

heybales

My hr and cal burns are always higher than I think they should be. For instance I can teach a spin class and talk the whole time with an average hr in the 160's max'ing in the 190's. According to the charts this shouldn't happen in your late 30's, but it does and I'm perfectly fine. Because the calorie burn is based primarily on hr, I feel is not completely accurate for me. Because of this I tend to only eat back about 60% of the calories I record. Heart rates and such are based on an average, and its possible you are just a bit outside of that. You can easily verify your HR monitor by doing a 15 second pulse count and multiplying by 4, if the monitor is good but you are higher than you think you should be talk with your doc just to make sure things are good. Otherwise keep on busting out the workouts, good luck!

Sadly the HRM setup and default values for women make it more of a chance for inaccuracy. Men luck out.

Women are also more likely to slow their metabolism down by underfeeding too far compared to men, and a slower metabolism also burns less calories than even the correct stats would indicate.

http://www.myfitnesspal.com/topics/show/459580-polar-hrm-calorie-burn-estimate-accuracy-study

Depending on the values you can manually adjust, probably at least MHR, perhaps VO2max also, you can correct it if you test for those values.
http://www.myfitnesspal.com/topics/show/466973-i-want-to-test-for-my-max-heart-rate-vo2-max

dreweth

I've been using my HRM during P90X for a couple weeks now, and from what I've read on here, I'm burning a lot more calories than average.... or my HRM is reporting high. I have a brand new Polar FT4. I'm 6'1", 174 pounds, 34 years old, and before P90X I was nearly completely sedentary... my exercise mainly consisted of carrying around a 20 pound baby, and a 0.7 mile walk between the train station and work (desk job).

For example, last night I did legs and back and ab ripper X, and my HRM said 1085 calories burnt. My average heart rate was 137, max was 173, and time in zone 1:06:03. I push pretty hard in these exercises, and the pull ups always get my heart rate up there (I'm sure that's where I hit 173).

But... really, 1085?

For comparison, doing C25K Week 2 Run 1 the other day (walking @4mph, running @6mph, 1% grade on the treadmill), I burned 385 calories in 30 minutes, according to my HRM. (average HR 137, max 165, Time in zone: 18:23)

Does this sound right to anyone else?

-Nate

Sounds right to me, if you are really "bringing it" during Legs and Back. My HRM says I have burned even more than that during that workout, though I have more weight to lose and am more out of shape than you may be.

Anyone that is saying "no, too high" may be jealous, but running (unless extreme HIIT) is not as hard as Legs and Back at full intensity. That is a monster burn, cardio and resistance workout, and one of the hardest of P90X for me, harder than plyo.

That said, I still don't eat all of those calories back, typically on big days like that. I usually subtract a few hundred calories because I don't feel like eat all of it back.

Lastly, do the math. You said ~385 calories with an in-zone time of 18 minutes, around 21 calories per minute of in-zone time. Your P90X workout was 61 minutes of in-zone time, which is only 18 calories per minute. How does that not make sense if you have the same average heart rate for in-zone time?

aweightymatter

I've been using my HRM during P90X for a couple weeks now, and from what I've read on here, I'm burning a lot more calories than average.... or my HRM is reporting high. I have a brand new Polar FT4. I'm 6'1", 174 pounds, 34 years old, and before P90X I was nearly completely sedentary... my exercise mainly consisted of carrying around a 20 pound baby, and a 0.7 mile walk between the train station and work (desk job).

For example, last night I did legs and back and ab ripper X, and my HRM said 1085 calories burnt. My average heart rate was 137, max was 173, and time in zone 1:06:03. I push pretty hard in these exercises, and the pull ups always get my heart rate up there (I'm sure that's where I hit 173).

But... really, 1085?

For comparison, doing C25K Week 2 Run 1 the other day (walking @4mph, running @6mph, 1% grade on the treadmill), I burned 385 calories in 30 minutes, according to my HRM. (average HR 137, max 165, Time in zone: 18:23)

Does this sound right to anyone else?

-Nate

Sounds right to me, if you are really "bringing it" during Legs and Back. My HRM says I have burned even more than that during that workout, though I have more weight to lose and am more out of shape than you may be.

Anyone that is saying "no, too high" may be jealous, but running (unless extreme HIIT) is not as hard as Legs and Back at full intensity. That is a monster burn, cardio and resistance workout, and one of the hardest of P90X for me, harder than plyo.

That said, I still don't eat all of those calories back, typically on big days like that. I usually subtract a few hundred calories because I don't feel like eat all of it back.

Lastly, do the math. You said ~385 calories with an in-zone time of 18 minutes, around 21 calories per minute of in-zone time. Your P90X workout was 61 minutes of in-zone time, which is only 18 calories per minute. How does that not make sense if you have the same average heart rate for in-zone time?

I can assure you I'm not jealous I still think it's better to err on the side of NOT eating back all those calories when you get a really high burn calculation, since we can never really get an accurate count of either calories burned or, really, eaten.