Can muscle turn to fat? It's been a year since I worked out regularly. Has the muscle I had before turned to fat?… and more of your questions answered here

Shape, May, 2004 by Suzanne Schlosberg

Q I haven't worked out in a year, so I think some of my muscle has turned to fat. I want to lose the fat before I start building muscle again. How do I do that?

A Your muscles may have atrophied, but they haven't turned to fat. "Muscle and fat are two separate and distinct types of tissue," says Cedric X. Bryant, Ph.D., chief exercise physiologist for the American Council on Exercise. "Muscle can't turn into fat any more than wood can turn into metal. But as muscles shrink because of inactivity, fat can fill the space where the muscles used to be, giving the mistaken impression that the muscles have turned to fat."

Start your new program with both cardiovascular exercise and weight training, Bryant advises. As you develop more muscle relative to fat, you'll notice more tone and definition, he says. "A pound of muscle will take up far less area than a pound of fat. So you'll look better even though your weight may not necessarily change."

To get back into exercising, see our pull-out poster "The Lean, Mean Boot-Camp Routine" on page 264. Don't be put off by the term boot camp: Our program is a 31-day plan that includes cardio and strength training, and it's designed for women who want to get into shape--or back into shape--for bikini season. (Also, see the answer below for more information on how to plan a sensible workout schedule.)

Q I want to include cardio, weight training and yoga in my fitness program, but I can't figure out how to squeeze them all in without exhausting my muscles. Is it a bad idea to lift weights and do yoga on consecutive days? What's a good schedule?

A "The answer depends on whether you're doing a tough yoga workout or a gentle one," says San Diego yoga instructor Mara Carrico, author of Yoga Journal's Yoga Basics (Henry Holt, 1997).

If your yoga practice is a more gentle one that emphasizes stretching, breathing and body alignment, it's fine to lift weights the day before or after yoga, Carrico says. In fact, if you have the time, you might even be able to do both on the same day.

The day after a strenuous yoga workout, however, your muscles won't be fresh enough to lift weights. Similarly, the day after a serious weight workout, your muscles will not have recovered enough to put their all into a vigorous yoga routine.

Each week, aim for two strength sessions, three to five cardio sessions (vary the intensity throughout the week) and two yoga sessions (one gentle, one vigorous). A sample schedule might be:

Monday Cardio (low-to-moderate intensity) and weights

Tuesday Rest or cardio (high intensity)

Wednesday Gentle yoga and cardio (low-to-moderate)

Thursday Cardio (low-to-moderate) and weights

Friday Cardio (high intensity)

Saturday Vigorous yoga

Sunday Rest

Q In addition to calories burned, time and distance, the cardio machines at my gym give readouts for METs and watts. What are these measurements, and should I pay attention to them?

A "These are ways to measure the amount of work you are doing, but for the average person, they're not very practical," says Dixie Stanforth, M.S., a lecturer in the kinesiology department at the University of Texas at Austin.

A MET is defined as a "multiple of the resting metabolic rate." One MET equals the amount of oxygen your body takes in when you're not moving. "MET values tell you how much harder you're working when compared with rest," Stanforth says. "So exercise performed at three METs requires three times the amount of oxygen consumed at rest."

A watt is a measure of power, equal to force multiplied by distance divided by time. "You generally see watts on rowing machines or bikes," Stanforth says. "Basically, this is a way of looking at how much power you are generating. For an athlete, this can be meaningful. You can see how much power you're generating in a given gear on your bike, for example. But for most people, it's overkill."

Rather than focus on METs or watts, focus on distance, time and intensity level. Many cardio machines have built-in heart-rate monitors, which can help you track your progress as well. If, say, you can exercise at level 7 on the elliptical trainer for 20 minutes at a certain heart rate and two months later you can work out for the same time at the same level at a lower heart rate, then you know you have become more fit. (You also can judge your progress by what is known as your RPE, or your rate of perceived exertion; that is, you're making progress when a workout feels easier.)

Q When I began strength training three months ago, I used to get that good muscle-tiredness feeling the day after a workout. I still lift weights with maximum effort and vary my routine, but I don't feel sore the next day anymore. Does this mean I'm not gaining new muscle?

A No. "Don't equate the value of a workout with how sore it makes you," says American Council on Exercise spokeswoman Dixie Stanforth. "When you're actively sore, it means the muscular damage has not healed, and you can't generate as much force." Reduced soreness is generally a good sign, Stanforth adds, because it means your body is quickly repairing the microscopic muscular damage that occurs during a workout. Soreness results primarily from the eccentric contraction, also known as the lowering phase of an exercise.