Heat's effect on calorie burn

Brenda_1965
Brenda_1965 Posts: 314 Member
I am training to run the 5k part of a triathlon, and today my daughter suggested that I run the 3 mile triangle outside my house. I live in the country, so it is part highway and mostly gravel. It is also VERY hilly. I did it in 44 minutes, and I had to walk the hills because it killed my butt to run them! I had been running at the Fitness Center in the air conditioning, and I was SHOCKED how much more energy it took to run in the heat! More calories HAVE to be burned running in the heat! Does anyone know?

Replies

  • Azdak
    Azdak Posts: 8,281 Member
    I am training to run the 5k part of a triathlon, and today my daughter suggested that I run the 3 mile triangle outside my house. I live in the country, so it is part highway and mostly gravel. It is also VERY hilly. I did it in 44 minutes, and I had to walk the hills because it killed my butt to run them! I had been running at the Fitness Center in the air conditioning, and I was SHOCKED how much more energy it took to run in the heat! More calories HAVE to be burned running in the heat! Does anyone know?

    Nope--it feels harder because you fatigue more easily, but no more calories. In fact, you might even burn less because the heat often prevents you from working as hard.
  • Yanicka1
    Yanicka1 Posts: 4,564 Member
    Nope sorry. Being cold do burn more calories but not heat.
  • no but I feel that running on road verses running on treadmill is harder and may be why you felt more energy expended.
  • gaylynn35
    gaylynn35 Posts: 854 Member
    I was curious about this also. It seems like I must burn more calories when I ride my bike at 1:00 pm then if I ride at 7:00 pm. I ride just as hard on both rides. So, just wondering!
  • pholbert
    pholbert Posts: 575 Member
    In the heat your body has to burn calories to cool it off.
  • You burn calories-constantly. Your body has a "Happy Medium" 98.6 temperature, now think....why do we sweat? It's our bodies way to cool down, so that our body temperature can stay at the "Happy medium." I like to think, if it's extremely hot, your body has to works THAT MUCH harder to stay in the "Happy Medium", same applies for working out in the cold. So yes, I like to think we burn more in the heat :D
  • George1567
    George1567 Posts: 107
    I have found that as I have got in better shape I see the same general cal burn for a given distance. If the pace is slower, it takes longer, the burn rate is less but over a longer time and ends up the same. If I go out and really push, the burn rate is higher, but I reach the distance and finish in a shorter time.
  • ninerbuff
    ninerbuff Posts: 49,030 Member
    Agree with the no answers. If burning more calories because of heat counted, then people in the South East should be a lot thinner. It's SO humid down there.

    A.C.E. Certified Personal and Group Fitness Trainer
    IDEA Fitness member
    Kickboxing Certified Instructor
    Been in fitness for 28+ years and have studied kinesiology and nutrition
  • WildcatMom82
    WildcatMom82 Posts: 564 Member
    My burns doing the same workout are always more when it's 90 degrees vs 70 according to my HRM.
  • Nope, heat doesn't increase calorie burn. But it takes much more effort = more calorie burn to do that outdoor run than it does to run on a treadmill.
  • rhonniema
    rhonniema Posts: 522 Member
    For me it's usually the same, just feels like you burn more because well you know there's no AC so you'll sweat more.
  • CarolinaGirlinVA
    CarolinaGirlinVA Posts: 1,508 Member
    I use my HRM when I walk and I have noticed my calories burned is more on hotter days. I walk the same exact route at a local park and my time varies +/- a minute. On cooler days I burn about 50-75 less calories than days it is hot (85F or more).
  • tigersword
    tigersword Posts: 8,059 Member
    In the heat your body has to burn calories to cool it off.
    False, sweating to cool down does not burn extra calories. The body has to work constantly to maintain body temperature, when you overheat and start to sweat, the entire system that keeps your body temperature from dropping shuts down.

    Think of a furnace in a house. When it's cold out, the furnace has to keep running to warm the inside of the house, when it's hot out, the furnace shuts down, because the heat from the outside warms the house up instead.
  • BaileyBoo13524
    BaileyBoo13524 Posts: 593 Member
    Just read an article that working out in the heat does burn more calories due to elevated heart rate. I've been working out in our workout room in the evening which is on the second story and it's a sauna! I have a HRM and I can definitely tell a difference in calories burned in the heat. Can't believe everyone here is saying no more calories are burned!
  • tigersword
    tigersword Posts: 8,059 Member
    Heart rate really has no direct bearing on calorie burn, other than for aerobic exercise. If your heart rate increases because it's hot outside, but you are sitting in a lounge chair, reading a book, you aren't burning more calories than if you were reading a book in an air conditioned room.

    The problem with HRM's is that an HRM is a "dumb" tool. It is programmed to calculate calorie burn based on change in heart rate, intended for steady state aerobic exercise. An HRM cannot differentiate between heart rate changes due to aerobic work, or for any other reason, so it just spits out whatever number it's programmed to spit out. That doesn't make it correct.
  • mcrowe1016
    mcrowe1016 Posts: 647 Member
    Heart rate really has no direct bearing on calorie burn, other than for aerobic exercise. If your heart rate increases because it's hot outside, but you are sitting in a lounge chair, reading a book, you aren't burning more calories than if you were reading a book in an air conditioned room.

    The problem with HRM's is that an HRM is a "dumb" tool. It is programmed to calculate calorie burn based on change in heart rate, intended for steady state aerobic exercise. An HRM cannot differentiate between heart rate changes due to aerobic work, or for any other reason, so it just spits out whatever number it's programmed to spit out. That doesn't make it correct.

    What he said^^^^ This is also part of the reason that HRMs do not accurately measure calories burned during strength training.
  • Brenda_1965
    Brenda_1965 Posts: 314 Member


    Thanks!!!!! This is an excellent article!!!
    Heat vs. Cold

    The answer to whether your body uses more calories if you are hot or if your are cold is: it depends. If you walk outside in cold weather, your body will immediately raise its BMR to compensate for heat loss and burn more calories. You will burn few extra calories in hotter weather unless you are exposed for a long period of time. On the other hand, if your internal temperature increases a few degrees, your BMR begins to rise quickly. A fever of 105 F, for example, represents an almost 50 percent increase in BMR. Burning calories at this rate can lead to tissue damage and threaten your life.


    Read more: http://www.livestrong.com/article/526014-does-your-body-burn-more-calories-if-you-are-hot-or-if-you-are-cold/#ixzz22uRqUuhD:flowerforyou:
  • Brenda_1965
    Brenda_1965 Posts: 314 Member
    Heart rate really has no direct bearing on calorie burn, other than for aerobic exercise. If your heart rate increases because it's hot outside, but you are sitting in a lounge chair, reading a book, you aren't burning more calories than if you were reading a book in an air conditioned room.

    The problem with HRM's is that an HRM is a "dumb" tool. It is programmed to calculate calorie burn based on change in heart rate, intended for steady state aerobic exercise. An HRM cannot differentiate between heart rate changes due to aerobic work, or for any other reason, so it just spits out whatever number it's programmed to spit out. That doesn't make it correct.


    I was running. Isn't that considered aerobic activity? Let me tell you, my heart rate was reaching dangerous levels! THANKS EVERYBODY! :yawn:
  • tigersword
    tigersword Posts: 8,059 Member
    That's the point though. Your heart rate elevates due to aerobic activity. That burns extra calories. It elevates more due to the heat. That DOES NOT burn any extra calories. The run felt harder because running outside on solid ground is harder than running inside on a treadmill.
  • xarge
    xarge Posts: 484 Member
    In the heat your body has to burn calories to cool it off.

    Hmmm... Sorry, that's what vasomotor control and perspiration is for. It would be a shame to get sweaty without a cause.
  • DopeItUp
    DopeItUp Posts: 18,771 Member
    Just read an article that working out in the heat does burn more calories due to elevated heart rate. I've been working out in our workout room in the evening which is on the second story and it's a sauna! I have a HRM and I can definitely tell a difference in calories burned in the heat. Can't believe everyone here is saying no more calories are burned!

    You can't believe everyone is saying the truth? I can't believe it either!
  • Martucha123
    Martucha123 Posts: 1,089 Member
    Just to make it clear
    heat didn't contribute to calorie burn, even though it has raised your HR so HRM will be off

    but running outside is much harder then running on the treadmill, so unless you walked a huge part of those 3 miles, I believe you did burn more kcals then usually. Not becaus of the heat, but because of the hills
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