High temp/humidity affecting rate of calories burned?

_Amy_Budd

So I did an hour of brisk walking this evening outside on a high school track. I do this activity at the same location twice a week, during my son's track practice. It was really warm and sticky there today, and though I always try to work hard through the walk, I was more sweaty than I usually am when I do this. Cut to the end of the walk - I check my HRM - 742 calories burned in the hour! Also, my heart rate was higher than it has been from the same activity.

So my question: Did the heat/humidity cause me to get a better burn than the same activity done when it's cooler out?

P.S. I was totally hydrated throughout.

LJSpady

I'd like to know too. I always see people in the gym were like 3 layer of clothes to make them sweat harder, I and I've always wondered if it actually makes the burn higher.

Losing2Live69

I don't know, but over 700 calories for an hour walk seems like a lot. How much do you usually burn? It is all based on your height, weight, age, and sex. If you are heavier you are going to burn more. Yes, the heat will make your heart beat faster. However, I don't know if your calorie burn is truly a lot higher than it usually is. I am having the exact opposite problem. I am on a medication that slows my heart rate. I can do very strenuous exercise and my heart rate wont get over 110. I was told by my trainer that my HRM was not accurately reflecting how many calories I am actually burning. I imagine it is the same for you. I would rather log in a lower amount than a higher amount...especially when it comes to eating back your exercise calories. I do know that in Bakram (SP??) Yoga it is done in a heated room and it burns a ton of calories...

musica814

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_Amy_Budd

I don't know, but over 700 calories for an hour walk seems like a lot. How much do you usually burn? ... I do know that in Bakram (SP??) Yoga it is done in a heated room and it burns a ton of calories...

I just went and scrolled back through my exercise diary - looks like I burn anywhere between 450-550 per hour with the brisk walk at track practice. So this is definitely higher, but is it crazy higher?

Also, if Bikram hot yoga burns a ton of calories, and people at gyms wear 3 layers to get a higher burn (as the previous poster said), then there could be something to it...

That being said, I hate the heat, so I'm not looking to intentionally layer up when I exercise. Just curious...

SuperMoniMonk

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CeejayGee

I know that heat affects your heart rate, which is why sitting in the hot sauna actually burns a decent amount of calories. So, i'd imagine that working out in the heat also burns more than working out in the cold.

SHBoss1673

heat can effect heart rate, but it doesn't significantly effect calorie burn, you are probably receiving erroneous results there. Since the HRM works off heart rate from averages, that's why the results are off. The body pumps blood faster to cool you down when you are hot (the blood acts like radiator fluid in a car engine), but that doesn't mean your body is burning significantly more calories than it would otherwise, just the extra calories needed to pump your blood faster, thats all, and that's a small difference. Many people think that sweat level or heart rate equates to calorie burn directly, when in fact, the real measure of calorie burn (other than direct heat measurement in a closed system, which would be super difficult to measure outside of a specialized lab) is how much oxygen you burn (assuming this is an aerobic workout, anaerobic workouts change everything), and that probably won't change based on a rise in temperature.

SHBoss1673

I know that heat affects your heart rate, which is why sitting in the hot sauna actually burns a decent amount of calories. So, i'd imagine that working out in the heat also burns more than working out in the cold.

sitting in a sauna doesn't burn a significantly higher calorie amount than sitting on a chair in your living room. slightly higher because your heart pumps harder, but only by maybe a calorie per minute or so.

That's a myth perpetuated by people who inaccurately read their HRM's and by sauna companies (which is sleazy IMHO). It's untrue.

LJSpady

heat can effect heart rate, but it doesn't significantly effect calorie burn, you are probably receiving erroneous results there. Since the HRM works off heart rate from averages, that's why the results are off. The body pumps blood faster to cool you down when you are hot (the blood acts like radiator fluid in a car engine), but that doesn't mean your body is burning significantly more calories than it would otherwise, just the extra calories needed to pump your blood faster, thats all, and that's a small difference. Many people think that sweat level or heart rate equates to calorie burn directly, when in fact, the real measure of calorie burn (other than direct heat measurement in a closed system, which would be super difficult to measure outside of a specialized lab) is how much oxygen you burn (assuming this is an aerobic workout, anaerobic workouts change everything), and that probably won't change based on a rise in temperature.

As your blood pumps faster, doesn't that 'cause you to breath faster and/or harder, making you burn more oxygen? That's where I always thought the correlation was between calorie burn and heart rate.

I've been considering wearing more when I workout to up my burn a bit. I mean even if wearing an extra undershirt and a hoody makes me burn an extra half of a calorie per minute (I weigh 340, so I get hot fast...lol) that's good news, cause my cardio workout is an hour and a half long. That's about 45 more calories per session. May not sound like much, but that comes out to about 225 calories a week. That's like adding another workout to my week.
Or at least that's how it seems.

RCKT82

This is a cool site..

http://www.shapefit.com/basal-metabolic-rate.html

It explains what conditions will affect you BMR... It does mention that a Higher External temp will increase your BMR, which I would assume will have the same affect on calories burned during exercise.

But like someone mentioned above... its going to be very little to no significance on your total calories burned because your body will compensate to cool itself through sweat.

rcshouldis

There actually is a relationship between calories burned and the environment in which you exercise. In my experience I will burn approximately 135 calories per mile when I am walking at around 3 .5 mph between 60 and 75 degrees. When the temperature rises to about 90 or above I burn about 170 calories for the exact same mile. I have been monitoring this for quite some time now with my heart rate /calorie monitor .

Timshel_

It's scortching here in Arizona. My calroeis burned is only slightly more now for the same amount of exercise, but I feel MUCH more exerted and sometimes it takes longer to do the same amount of exercise.

3dogsrunning

Heat/humidity is one of the factors that affects the accuracy of HRMs.

"• Numerous confounding factors affect the HR response to PA and therefore the HR vs. VO2 relationship.
These include high ambient temperature or humidity, time of day, emotional state/stress, fatigue, hydration status, food, caffeine and nicotine intake, previous PA, illness, body position, mode of exercise and use of limbs.

If you want to read the studies those references are pointing to, Page 36 in the following study.
https://researchspace.auckland.ac.nz/bitstream/handle/2292/305/02whole.pdf?sequence=9
"
http://www.myfitnesspal.com/topics/show/773451-is-my-hrm-giving-me-incorrect-calorie-burn

Your HRM will give you a higher reading, but you do not actually burn more calories in more heat, assuming you are doing the same intensity. It may feel harder, but it does not burn more calories.

also
http://www.myfitnesspal.com/blog/Azdak?month=201003

Harlequinndancer

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rcshouldis

If you walk at a brisk rate for an hour , something around 3.5 mph, and burned 742 calories, then you burned about 212 calories per mile. This is quite possible for a big man who is carrying more weight than a smaller man. I have burned up to 180 calories per mile in hot weather conditions , on occasion. I weigh around 250.

katy84o

A few weeks ago, I went out for a walk it wasn't particularly hot or humid and I looked down at my watch and it said I had already burned almost 200 calories and I had only been walking for 15minutes. I had washed my strap the night before and I'm guessing that something had gotten to wet and was throwing off the recording. I let it dry out for a few days and haven't had any problems.

Maybe the extra humidity was causing a false reading?

*Edit to add: I went on a alternating jog/run tonight for an hour and twenty minutes. It's very humid where I'm at, DC area, and I burned 540 calories/ my hrm. Maybe it could also be your battery making things go a little haywire.. ?