FAQ

Author: Cleaves M. Bennett MD FACP

What should I do on hot days when I perspire a lot? Should I take salt tablets or drink Gatorade?

First of all, you don't need salty water. The salt in your diet is already a problem, so don't add to it. And you don't need any extra sugar, either. Your fat stores are being converted to sugar. You just need to replace the water you've lost during exercise. That's all. Your body knows just what to do—so let it do it, naturally, particularly if it's a hot day, or if you live in a very dry climate, just drink a few glasses of plain water, slowly and carefully. That'll do the trick.

Philip Felig and colleagues at Yale University have been working in this area and have published their results in an issue of the New England Journal of Medicine (1982). Their research showed that it takes several hours of endurance exercise (such as cycling or running) to use up stored fuel and drop the blood sugar level, even in a lean athlete. Even then, performance doesn't suffer—nor is it improved by drinking glucose and water.

And those of us with some fat stored around the tummy or hips needn't worry at all about running out of fuel! In fact, if you exercise before eating, you will derive more of your energy from burning up those unwanted fat stores. (Obesity Research 2003 Feb; 11:247-56). That’s what they’re there for!

I know how it can be. And for the moment, about all I can offer you is my sympathy. If you're really exercising and stretching the muscles, you may well be pretty stiff and sore from time to time. In fact it's one way to tell you're doing a pretty good job.

The test is that when you're stiff and sore and you do your stretching and begin to exercise, it should get better. If it gets worse when you exercise, you should go see your doctor about it.

Yes, it does. It's very important, if you're going to be exercising outdoors, to be very aware of the quality of the air. It's a mistake to exercise in smoggy conditions. When you exercise, your lungs take in more air and if it's full of carbon monoxide and other pollutants, this can be really harmful. If it's smoggy, find somewhere else to exercise. Or stay inside.

Hot tubs and saunas are more designed to reduce muscle soreness and stiffness, particularly after weight lifting, stretching, or calisthenics. Be very careful about getting into a hot tub while your body's still hot (and trying to lose heat) after a good aerobic workout. I don't recommend it. Wait for a while, until you've cooled down.

I'd also recommend that you be careful about hot tubs and saunas if you're on blood pressure pills—especially the central acting drugs, methyldopa, clonidine and guanabenz. Ask your doctor what he thinks—I recommend extreme caution if you're on these pills, because the heat may cause you to dilate your blood vessels and faint.

Your exercise prescription after a treadmill test should take into account the fact that your heart rate response to exercise is blocked by the drug. Beta blockers almost always do this. If your own maximum heart rate (with the drug) is 120, you'll probably be able to exercise at pretty near ninety to a hundred percent of that figure, instead of eighty percent. But ask your doctor—he's the best judge, because he's seen your electrocardiogram. Another test you could use is the talk test that we described earlier. You should be able to carry on a conversation while you walk (or run or cycle), if you're not overtaxing your body.

When you stop taking the beta blockers, or reduce the dose, you'll need a new exercise prescription, because your THR will change, sometimes dramatically. Again, your doctor or cardiologist is the one to talk to about this.

All right, And here's one final piece of advice. If you need to lose weight, and you're just beginning a regular exercise program, don't use food as a reward system for exercising. You have a beautiful mechanism inside you that matches your caloric intake with how much you burn, and exercise will tend to make you more aware of it. But I've seen people jog every day for two years and not lose a pound—and all because they rewarded themselves with snacks every time they'd been good and done their exercise! Exercise can really help you lose weight! So give it a chance.