People often use how much they are sweating as a guide to how hard they are exercising and how much good it must be doing them. Others think that if they are sweating a lot, it is a sign that they aren’t very fit or that someone who doesn’t even break into a sweat must be fitter than they are.
While it follows that the harder you are exercising the more likely you are to get hot and sweat, the opposite isn’t necessarily true. Just because you are sweating a lot doesn’t mean you are working hard.
I read an article in the newspaper a week ago about a form of yoga that you do in a humid 38C room. The article stated that participants, some of who were athletes and no doubt very fit, claimed it was the hardest thing they had ever done and that people often felt nauseous and dizzy. I’m sure they did find it hard and they felt bad while exercising. However I expect the heat had more to do with it than the exercise.
When you exercise blood is directed to the working muscles to supply the oxygen and fuel needed. When you get hot, blood is directed to the skin so that heat can be lost from the body to keep your internal temperature constant.
When you exercise in a hot environment, the heart and lungs have to work extra hard because they are trying to get blood to both the muscles and the skin. As a result, blood is diverted away from other organs. This means a person exercising in the heat will usually have a higher heart rate giving them the perception that they are exercising harder. People feel nauseous because blood is diverted away from the gut; this also adds to the perception of working harder.
Because we use our heart rate and breathing to ‘assess’ how hard we are working, when we exercise in the heat, it often feels like we are working harder. Add to this the feeling of nausea and it feels like we are working very hard, even if we aren’t doing any more than usual. I think this explains why the athletes doing yoga in a humid 38C room perceived it to be so difficult.
Fitness is predominantly about what is going on inside the muscles than just whether the heart had to pump faster to keep up with competing demands for blood.
What are the lessons from this for you?
- Don’t intentionally exercise in extremely hot environments unless you are training for some event that will be held in an extremely hot environment.(e.g Hawaii Ironman, a marathon in the Sahara) The added demands it places on the heart and heat loss systems and the potential risk and discomfort aren’t worth it for general fitness.
- Don’t exercise in extra clothing to “heat up” and sweat more. You might weigh less when you finish your exercise, but it will be fluid loss not fat loss and the risk of overheating for no added fitness gain isn’t worth it.
- Try to keep cool while exercising. Your heart and lungs can then focus on getting blood to the working muscles where it is needed. You’ll perform better and feel better, which means you will probably enjoy it more and do it again.
- Don’t believe that just because you feel bad while exercising it is better for you. Exercise should feel a bit uncomfortable while you are doing it but you shouldn’t necessarily feel sick.
- You don’t have to exercise in the heat to be more pliable and elastic. Being in a hot room doesn’t mean the muscles are properly warmed up with adequate blood flow. A gradual warm-up of the muscles you are using is more important than having hot skin and sweating a lot.
- Focus on improving your performance. How you feel and look is important, but they are outcomes of getting fitter.
