The highlight of Rich Naab's day comes at 6 a.m., when he arrives at Club Julian in Ross for his daily workout.

Darrell Sapp, Post-Gazette Trainer George Latta supervises Richard Naab during a weight-lifting session at Club Julian in Ross. Click photo for larger image.

"My wife says go to the spa," said the Shaler resident. "If I stay home, I'm miserable."

Mr. Naab, 61, must use a wheelchair, but that doesn't slow him down.

On Mondays, Wednesdays and Fridays, Mr. Naab lifts weights under the supervision of personal trainer George Latta, 63, a retired health and physical education teacher. He does four to five sets of 10 different exercises, 10 repetitions each. On Tuesdays and Thursdays, he swims.

Mr. Naab has been working out for 10 years, which has helped him recover from the cancer, radiation treatments and 15 back operations that left him without the use of his legs.

"Exercise helps people live longer, better," said Dr. Judith Black, medical director for senior products for Highmark Blue Cross Blue Shield. "It keeps them healthier and more engaged socially, so they have a better outlook on life."

Beginning at about age 50, men and women begin to lose muscle mass. This makes it harder to do everyday activities, and easier to gain weight, because metabolism slows.

But a 50-year-old with a balanced exercise program can be more fit than a sedentary 30-year-old, Dr. Black said.

An exercise regimen for people over 50 should include stretching and flexibility exercises; cardiovascular exercises, and resistance training, she said.

The most important, especially for older women, is weight lifting, said Debbie Truxal, 49, a personal trainer at Bally's in McCandless.

Resistance training prevents bone loss and improves posture, which is especially important for post-menopausal women, Ms. Truxal said.

"The more weight-bearing you [do], the more bone density you keep," she said.

Resistance training, coupled with other weight-bearing exercises, can help prevent kyphosis, the forward bending of the upper spine known as dowager's hump, Dr. Black said.

"Kyphosis is caused by a lack of minerals in the bone, so the vertebrae in the spine collapse," she said. Weight-bearing exercises, as well as walking and jogging, promote bone growth and thus prevent this bone loss, known as osteoporosis.

Because it builds muscle that burns calories 24 hours a day, seven days a week, weight lifting is also more effective at weight control than cardiovascular exercise, Ms. Truxal said.

"A lot of women have gone most of their lives without doing any strength training, which is the key to fitness and permanent weight control," agreed Kara Levine, 33, manager of the Curves franchise in Mt. Lebanon.

"For every pound of muscle that you put on, that's 50 more calories that your body burns per day," she said.

Ms. Truxal said the greatest difficulty she has with her clients is getting women to lift weights, and getting men to lift weights properly.

"It's about the form, not about how much weight you can lift," she said.

Weight lifting "is a huge issue with women," Ms. Truxal said. "They haven't been welcome in the weight room. I call it 'the dark side.'"

Women needn't fear they'll bulk up, because they lack the testosterone required to build big muscles, said Ms. Truxal, whose slim, trim appearance belies the fact that she can leg press 360 lbs.

It isn't hard to get men into the weight room, but men often will sacrifice form to lift ever heavier weights, and good form is the key to getting maximum benefit from resistance training, she said.

It takes at least three sets of 10-12 repetitions each to obtain the maximum benefit from a weight training exercise, said Ms. Truxal and Tedd Stahl, 33, a personal trainer at the Oxford Athletic Club in Pine.

You should lift as much weight as you can without sacrificing proper form, but it is better to lift too little weight than too much, Mr. Stahl said.

"You can always do another set," he said. "If you kill yourself on the first set, you're done."

If time permits, it is wise to combine resistance training and cardiovascular training in the same workout, Ms. Truxal and Mr. Stahl said.

Both recommend starting a workout session with a warm-up of five to 10 minutes of a light cardiovascular exercise such as walking on a treadmill or cycling, followed by weight lifting, beginning with the larger muscle groups.

Doing cardio exercises immediately after weight training accelerates fat loss, Ms. Truxal said.

"In the first 20 minutes of exercise, you burn sugar," she said. Only after that do you get into fat."

Stretching should be done after a workout, when the muscles are warm, not before, Ms. Truxal said.

"Stretching is not a warmup," she said. "Those are cold muscles. You're just asking for a [muscle] tear."

For those who have little time in their daily schedules for exercise, or who are intimidated by the weight room, the circuit training program offered for women by the Curves franchises and for both genders by the BodyBar, McCandless, combines resistance and cardiovascular training in a single 30 minute workout.

The circuit consists of 12 hydraulic machines on which all the basic weight lifting exercises can be performed. The machines automatically calibrate resistance on the basis of the strength of the exerciser. The harder you push or pull, the more resistance you get.

The 12 machines permit the exerciser to do 24 exercises, working one muscle when you push out, and its antagonist when you pull back. For instance, the bench press becomes a rowing exercise.

Exercisers spend 40 seconds on each machine in the circuit (exercisers are told when to switch machines by a tape that plays upbeat music). Twice around the circuit constitutes a workout. That, and five minutes of stretching afterward, can be accomplished in 30 minutes.

"It's fast, and with the music and everything, it just goes faster," said John Sherman, 60, a retired school social worker who has lost 25 pounds since he started working out at the BodyBar.

Because the hydraulic circuit doesn't tear muscles down, it can be performed every day. Weight lifters must give the muscles they exercise a day to recover, often more if they are older.

There's never a need to change weights on the hydraulic machines, and they're safer, said Ms. Levine.

"Up to 85 percent of weight injuries occur in lowering weight," she said. "That doesn't happen with hydraulics."

Women like the atmosphere of the hydraulic circuit better than the weight room, said Margarite Labanc, director of operations at the BodyBar.

"This is a nice social exercise," she said. "You can talk to the person across from you."

But the equipment isn't sissy, insisted Fred Como, the BodyBar's manager. "We've got Army Rangers, Marines, Navy SEALs using this equipment," he said.

Retirees can't complain that they haven't the time to exercise. And under the Silver Sneakers program, Highmark offers seniors free memberships at 150 health clubs in western and central Pennsylvania.

About 35,000 area seniors are taking part in the Silver Sneakers program, Dr. Black said. A study of 3,000 of them indicated the more they go to the gym, the less they need to go to the doctor, she said.