SHAPE UP
Your exercise misconceptions might need a reality check

By Charles Stuart Platkin

Interval training — brief, high-effort spurts — may be pointless. Washington Post

Q. Does interval training burn more calories?

A. Interval training consists of intermittent bursts of increased intensity while doing an aerobic activity. For example, if you walk for 60 minutes and want to incorporate interval training, about every five minutes you would walk at a much faster pace for two minutes or so, then go back to your normal pace.

The theory is you burn a lot more calories in that time than if you were to simply walk without increasing your intensity. "Yes, interval training can burn more calories; however, there are also periods after the high intensity is completed during which you might bring your intensity to even lower levels than when you started — this could counteract any of the extra calories you just burned," explains Walter Thompson, professor of exercise science at Georgia State University.

Even if your "starting" pace remains constant throughout the activity, any increase in caloric expenditure would be minimal. "In most interval training situations, you might only burn an additional 3 to 5 percent," adds Thompson.

Walking at a moderate pace for an hour burns about 238 calories. If you were to do interval training — by incorporating six two-minute intervals of brisk walking — you'll only burn a total of six more calories for all that extra intensity.

Q. Should you work out when you're sick?

A. Ask yourself the following questions: Is your heart rate elevated? If so, you should not be exercising. "Your heart can beat as much as 15 beats more per minute when you are sick, and if you add exercise on top of that, you're putting yourself at a higher risk for a heart attack and/or cardiomyopathy," says Dr. Stephen Rice, a sports medicine specialist at the Jersey Shore Medical Center in Neptune, N.J. "Not only that, but sometimes we overcompensate when we're sick, and work out even harder, which only increases any potential danger."

Do you have a fever? If so, you should not be exercising, because you could become dehydrated. "Also, your body is fighting the infection and needs energy to keep up that battle, and any exercise is probably not helping," says Rice.

Listen to your body. Do you have severe muscle aches and pains, or just a runny nose? Also, if you have any serious respiratory illness, avoid exercise.

However, if you feel up to it and you answered no to all the above questions, "Exercise could actually make you feel better and give you a much needed boost," offers Rice.

Q. Does it add up?

A. Do you have to do continuous cardiovascular training for it to be useful? What if you exercise for 10 minutes three times a day, instead of 30 minutes all at once — is this really just as effective?

Yes, according to a number of studies, including one published in Medicine and Science in Sports and Exercise, in which 24 sedentary women walked 30 minutes all at once five days a week, while a second group of 24 sedentary women walked three times a day for 10 minutes (also five days a week).

The improvements in cardiovascular fitness were virtually identical in both groups. Yet another study showed that continuous exercisers lost more weight and decreased their percentage of body fat while the intermittent group did not.

"From an overall health perspective, the significant cardiorespiratory fitness and HDL increases are much more important than the small amount of weight lost in the continuous group. You can do aerobic training all at once or break it up into smaller chunks throughout the day. The health and fitness benefits are about the same," explains Steve Farrell, of the Cooper Institute in Dallas.

Q. Does exercise make you eat right?

A. Sure, it makes sense that if you start working out, you might want to take better care of yourself and eat less. But that isn't always the case. In fact, the reverse could actually occur. "People tend to think, 'I'm exercising and burning more calories, so I can eat whatever I want,' " says Joseph Donnelly, an exercise physiologist at the University of Kansas.

Charles Stuart Platkin is a syndicated health and fitness writer.