Putting back the clocks for winter usually marks the time when it suddenly gets cold, and this year is no exception. We may not feel like leaving the sofa, but exercise warms us up – and we need to be warm to exercise properly. How does all this work, and why is it so important to warm up before exercise?
With the annual energy price increases much in the news, the nights drawing in and the temperatures dropping, it is time for all of us to dig out the winter coats and try to find out what happened to last year’s warm hat. However there is no need to shiver – our bodies are designed to keep a comfortable temperature and exercise is an important way to do just that.
As most people will know, human beings belong to the type of animal known as warm-blooded. This means that we regulate our own temperature and are not dependent on heat from our environment. While there are limits to the temperatures that we can tolerate without extra protection, being warm-blooded allows us to keep moving without needing to seek sunshine, and to cool ourselves off if we do get overheated. Our ability to control body temperature is one of the facts of life that we take for granted. Only those for whom this function has gone wrong will be able to tell how important it is.
The average human needs about 2000 calories from food each day, and many of these are used to keep us warm. The human body outputs an average of 100 watts of heat from these calories, as well as maintaining all body functions. Generally our body heat does not make too much of a contribution to heating our homes, but in a large crowd we can generate lots of heat even when standing still. Anyone who has been in a crowded and badly ventilated meeting room will know about this effect.
So if we use calories to keep us warm, does that mean that being cold will burn extra calories and so help us lose weight? Sadly this is yet another weight loss myth – while we do use slightly more calories if we are cold, the difference is tiny and will have no noticeable effect on weight. So forget any idea of losing weight by sitting in a cold bath. Not only does this not work, it is no fun at all at this time of year!
There’s no escape from the facts - exercise in conjunction with healthy eating is the only way to control weight. As soon as we start moving around, our body temperature rises. This is because we are using calories (a unit of energy) to move, and some of that energy is being turned into heat. Even light exercise will warm us up. We usually start a walk well wrapped up, but it is always good to wear layers as most people find that they are feeling warmer within a few minutes of leaving the house.
Those who spend a lot of time at home can use exercise to keep down the bills. As well as dressing sensibly indoors, we can keep warmer by moving about. So if you are working at home at the computer and feeling cold, take a few minutes to do some housework or even go up and down a few stairs. If the kids are grumbling about the cold and you can’t go out for any reason, take a few minutes for a mini-workout. Put on some music and dance, or even find some short exercise videos online. Everyone will soon be warmer – and probably giggling too.
It is all right to start gentle dancing from cold, but we need to be more careful for more serious workouts. Cold muscles are much more vulnerable to injury if stressed, which is why it is so important not to commence strenuous exercise from a standing start. Cold makes muscles contract to retain heat in the body core, so straining them in sudden movement is very likely to push them too far. This is why no reputable fitness instructor will allow anyone into their class if they are more than a minute or two late, as missing out the warm up phase means that there is too high a risk of an injury.
Warm ups are built into tennis matches and football games, and are not just for human sports – riders should always take the time to allow their horse to warm up with gradual increase of pace before starting an event. Anyone doing unsupervised strenuous sport also needs to remember to warm up. For instance, skiers should not go straight off on a difficult run after a long ride on an exposed lift. Despite peer pressure to get moving, it is a good idea to spend a few minutes marching on the spot and doing some arm exercises to loosen up muscles. This makes the demands of skiing on the body much less likely to cause injury.
Whether up a mountain, at home or in the gym, warm muscles are healthy muscles. So dress for the occasion and keep moving!
by Jessica Ward
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