Heat makes work and work makes heat
June 29, 2009 3:23 AM Subscribe
Which burns more calories - exercising in the cold or exercising in the heat?
Given that you do the same intensity of workout (say a 6 mile run at 12 minute miles) with the same amount of physical fitness, would you burn more calories (ie work harder) exercising in the heat or the cold? Note that I'm talking UK winter vs summer rather than artic vs desert.
Given that you do the same intensity of workout (say a 6 mile run at 12 minute miles) with the same amount of physical fitness, would you burn more calories (ie work harder) exercising in the heat or the cold? Note that I'm talking UK winter vs summer rather than artic vs desert.
I think the answer to your question is going to depend on the amount of energy consumed by the body for thermoregulation. I think in the situation you're describing there are going to be a number of variables, like the surface-to-volume ration of your body or wind chill, that would make a difference in that. But without being a biologist or sports medicine person or anything I'd be inclined to agree with le morte de bea arthur that in a mild climate like the U.K. I wouldn't expect the difference to be much.
As far as extreme cold environments, this U.S. military publication Nutritional Needs in Cold and High-Altitude Environments says the following:
As far as extreme cold environments, this U.S. military publication Nutritional Needs in Cold and High-Altitude Environments says the following:
posted by XMLicious at 4:03 AM on June 29, 2009Exposure to cold environments has been shown to increase the basal energy needs relative to the basal energy requirements measured under thermoneutral conditions, which has been attributed to the increased energy demands of thermoregulation in the cold.
Response by poster: OK thanks - but it seems such hard work when it's warmer! THink that's just being English and more used to being cold and wet!
And yes, I'm being careful. Only doing runs in the early morning (too many drunks around late evening) thanks though!
posted by LyzzyBee at 5:35 AM on June 29, 2009
And yes, I'm being careful. Only doing runs in the early morning (too many drunks around late evening) thanks though!
posted by LyzzyBee at 5:35 AM on June 29, 2009
Could you be getting dehydrated? Especially if you were drinking the night before that might be a possibility. Or maybe if there's sun in the morning in the summer but not in the winter.
But I certainly find it more uncomfortable when it's warmer too.
posted by XMLicious at 5:40 AM on June 29, 2009
But I certainly find it more uncomfortable when it's warmer too.
posted by XMLicious at 5:40 AM on June 29, 2009
OK thanks - but it seems such hard work when it's warmer! THink that's just being English and more used to being cold and wet!
It feels harder because the heat that you're generating isn't dissipating off you as efficiently, which increases fatigue-- in winter, the heat you make is dissipating into the cool air. In summer, it's sticking around in your muscles and helping produce the lactic acid that signals that you're nearly done.
Unfortunately, the difference is comparable to two days with similar weather with different enjoyment levels: some days you feel great and the miles fly by and some days you feel off and every step is a chore. Just because it sucks to be out there but you're sticking with it doesn't mean there are added benefits. I've strongly wished that weren't true a number of times!
posted by Mayor Curley at 6:21 AM on June 29, 2009
It feels harder because the heat that you're generating isn't dissipating off you as efficiently, which increases fatigue-- in winter, the heat you make is dissipating into the cool air. In summer, it's sticking around in your muscles and helping produce the lactic acid that signals that you're nearly done.
Unfortunately, the difference is comparable to two days with similar weather with different enjoyment levels: some days you feel great and the miles fly by and some days you feel off and every step is a chore. Just because it sucks to be out there but you're sticking with it doesn't mean there are added benefits. I've strongly wished that weren't true a number of times!
posted by Mayor Curley at 6:21 AM on June 29, 2009
It's more than just cold or heat. Wind, humidity and air movement play a factor, too. For example, cold + wind = increased thermal "debt" as the wind carries away warm air. Heat + humidity - wind = more heat, because sweat is not being evaporated in the unmoving, humid air.
posted by Cool Papa Bell at 6:54 AM on June 29, 2009
posted by Cool Papa Bell at 6:54 AM on June 29, 2009
I saw on man vs wild with Will Farrel that is takes 6000 calories a day to survive in the cold. I'm going to say that it is harder in the cold. Not only are you doing the activity but you are fighting to stay warm.
posted by Mastercheddaar at 6:59 AM on June 29, 2009
posted by Mastercheddaar at 6:59 AM on June 29, 2009
You are working harder. Look at the Physiology of Sport and Exercise, and search for "Physiological responses to exercise in the heat" the relevant pages start on 261. If I understand it correctly, and I am looking at a different edition at home than the one I linked to, the intuition is that when you are running in the cold you are mainly sending blood to your muscles to generate energy to move them but when you are running in the heat you are also trying to send blood to the skin to evaporate and cool you off, so your muscles dont get as much blood as they want. Humidity, and decreased efficiency of evaporation, could only exacerbate the problem.
posted by shothotbot at 7:05 AM on June 29, 2009
posted by shothotbot at 7:05 AM on June 29, 2009
(I meant to say, You are working harder IN THE HEAT. Also, when its cold and you are exercising you get at least some of your heat for free as a byproduct of the exercise).
posted by shothotbot at 7:08 AM on June 29, 2009
posted by shothotbot at 7:08 AM on June 29, 2009
From google "cold weather burn more calories":
You burn fewer calories when you exercise in cold weather than you do when it's hot. The hotter it is, the more extra work your heart has to do to prevent you from overheating. More than 70 percent of the energy produced by your muscles during exercise is lost as heat. So the harder you exercise, the hotter your muscles become. In hot weather, not only must your heart pump extra blood to bring oxygen to your muscles, it must also pump hot blood from your heated muscles to your skin where heat can be dissipated.
On the other hand, in cold weather, your heart only has to pump blood to your muscles and very little extra blood to your skin to dissipate heat. Your muscles produce so much heat during exercise that your body does not need to produce more heat to keep you warm. So your heart works harder and you burn more calories in hot weather. This information should not discourage you from exercising when it’s cold, because staying in shape is a year-round proposition. However, it may help to explain why so many people find the pounds creeping on in the wintertime, even when they stay active.
posted by wolfkult at 8:18 AM on June 29, 2009
You burn fewer calories when you exercise in cold weather than you do when it's hot. The hotter it is, the more extra work your heart has to do to prevent you from overheating. More than 70 percent of the energy produced by your muscles during exercise is lost as heat. So the harder you exercise, the hotter your muscles become. In hot weather, not only must your heart pump extra blood to bring oxygen to your muscles, it must also pump hot blood from your heated muscles to your skin where heat can be dissipated.
On the other hand, in cold weather, your heart only has to pump blood to your muscles and very little extra blood to your skin to dissipate heat. Your muscles produce so much heat during exercise that your body does not need to produce more heat to keep you warm. So your heart works harder and you burn more calories in hot weather. This information should not discourage you from exercising when it’s cold, because staying in shape is a year-round proposition. However, it may help to explain why so many people find the pounds creeping on in the wintertime, even when they stay active.
posted by wolfkult at 8:18 AM on June 29, 2009
I run much slower in the heat than I do in the cold. From 10 degrees Fahrenheit to 70 degrees, my times don't vary much. However, as the weather reached 90 in the last week or so, my pace per mile slowed significantly. Thus, I'd say being in the heat causes you to use more energy than in the cold.
posted by pyrom at 8:21 AM on June 29, 2009
posted by pyrom at 8:21 AM on June 29, 2009
Exercise in the temperature that will allow you to exercise the longest with the most comfort. It doesn't matter what temperature it is when you work out. It just matters if you keep doing it. Any ambient temperature difference will not increase you ability or burnt calories in significant digits. But make sure to warm up your muscles and to keep cool (yes that's right).
posted by Napierzaza at 8:28 AM on June 29, 2009
posted by Napierzaza at 8:28 AM on June 29, 2009
Response by poster: Thanks everyone - I appreciate your input! I'm careful with my exercising, make sure I'm hydrated (I don't drink alcohol so I don't need to worry about that one), keep in the shade as much as I can, and I try to make sure I don't overstrain myself, either by adjusting my activity (running slower) or the environment (eg I have a speedwork run to do on Weds, so I'm going out at 5am at the latest, when it SHOULD be cooler)
posted by LyzzyBee at 10:25 AM on June 29, 2009
posted by LyzzyBee at 10:25 AM on June 29, 2009
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I think I'd recommend confining your summer runs to the early morning or late evening in the next week though. Temperatures look set to reach 30C in parts of the UK, and unless you're used to it that could be really unpleasant.
posted by le morte de bea arthur at 3:41 AM on June 29, 2009