A Weighty Issue for Exercise Buffs
By Bob Calandra
WebMD Medical News

Reviewed by Dr. Craig H. Kliger

March 19, 2001 -- Weight training is no longer the exclusive domain of the flex and pecs crew at the gym. Today, many people seeking a well-rounded workout include some form of resistance training. But until recently, weightlifting was the Rodney Dangerfield of exercise -- it never got any respect.

That view is changing as evidence mounts that weights not only tone and build the muscles you can see, but may help another very important muscle you can't see: Your heart.

"We have done studies and found that weight training is indeed safe and also probably beneficial" to the heart, says Gerald Fletcher, MD, a cardiologist with the Mayo Clinic in Jacksonville, Fla., and a spokesman for the American Heart Association (AHA).

The AHA has come a long way in its position on resistance training. While doctors and exercise physiologists for years have routinely supported the notion of heart benefits from aerobic exercise, they pretty much have dismissed the notion of benefits from weightlifting. In fact, the consensus among cardiologists a decade ago was that hefting free weight was downright dangerous for people with cardiovascular problems because it stressed the heart and depleted it of oxygen.

The fact that studies searching for other evidence of weightlifting's advantages often were contradictory did not help resolve the issue. For example, for every one that showed resistance training reduced LDL (low density lipoproteins, the "bad" cholesterol) and increased HDL (high density lipoproteins, the "good" cholesterol), another followed saying it didn't.

Doctors now recognize that weight training contains an aerobic component. But the real merits of resistance training may not be found in that aspect or in blood levels, but rather in overall changes in the body. This year, the AHA issued a position paper that credited strength training for reducing resting blood pressure.

Fletcher still cautions people with high blood pressure to be careful when doing arm exercises, but endorses weightlifting as a part of most fitness plans. "We are really more liberally suggesting supplementing the aerobic experience with resistance exercise," he says. "For healthy people it is something they need, because it is beneficial as well as aerobic."

Wayne Westcott, fitness research director at the South Shore YMCA in Boston, Mass., couldn't agree more. Westcott has spent the better part of 30 years preaching the virtues of weight training for everyone -- young and old, healthy and sick.

"The cardiovascular system doesn't act independently of the muscular system," says Westcott, author of 16 books on strength training and fitness. "Every muscle you have acts as an auxiliary heart."

Having strong muscles is especially important for people with heart problems. Many cardiac patients, Westcott says, stress their hearts doing simple, everyday activities like walking up stairs, painting a wall, or trying to open a stuck window. "But strong muscles [help] accomplish these tasks easily," he says. "The better the condition of your muscles, the more they can help your heart."

Adding resistance to your exercise program, Westcott says, makes the heart pump faster. That forces the left ventricle -- the part of the heart that pumps blood to most of your body -- to worker harder and become stronger. Just like other muscles, the heart responds to hard work by growing thicker, stronger walls. "You get a larger left ventricle that pumps more blood with each beat, and you get a stronger pump and you can have a lower resting heart rate," he says.

If a healthier heart isn't enough reward, there are some other benefits that might motivate you to start pumping iron. For instance, would you like to shed a few pounds? An Ohio University study on the effects of resistance training on lipoprotein concentrations that appeared in last year's first quarterly issue of the Journal of Strength and Conditioning Research reported no change in those blood parameters. But the study did note changes in the subjects' bodies. "The training program resulted in significant alterations in body composition (decreased in percent of body fat) and fiber composition," the authors wrote.

That makes sense, says Westcott, who has conducted his own studies on resistance training and weight loss. Here' s why: In a 30-minute session of weight training, most people burn 260 calories, Westcott says. But resistance training gets the body so revved up that two hours after you've grunted the last repetition, your body is still burning calories at a supercharged rate. "You don't come back to a normal metabolic rate for the next two hours," Westcott says.

Want another reason to become friends with some dumbbells? A Tufts University study, published in the August 1994 issue of the American Journal of Clinical Nutrition, found that people ages 56 to 80 who weight-trained three times a week increased their resting metabolic rate by 7%. The participants gained three pounds of muscle and lost four pounds of fat while increasing their daily caloric intake by 15%.

"Strength training should be part of every weight loss program," Westcott says.

The American Heart Association recommends performing an aerobic workout six days a week for 30 minutes and two to three weight training sessions a week. But if you're like most Americans, you don't exercise because you think you don't have time to press some pounds. Not true, say Westcott and others in the field.

"Give me 10 to 15 minutes a day, two days a week and you will see a difference," Westcott promises.

If you want to start a weight workout, Westcott suggests that you first talk to your doctor and have a complete physical. Then, when you're ready, you can begin with these basic exercises:

A chest press or another pushing exercise.
A rowing exercise or another type of pulling exercise.
A major leg muscle exercise like a squat or leg press.
A core body exercise for the midsection, like sit-ups or crunches.

Westcott suggests weight training every other day, with an aerobic workout on the off days.

"In most studies, if we are doing 15 to 20 minutes of strength training, we do 15 to 20 minutes of aerobics," he says. "You don't have to do a lot to get fairly significant changes."