Who is in the gym?
According to annual surveys by the Boston based International Health, Racquet and Sportsclub Association that represents many of the nation’s 30,000 health clubs, membership among adults aged 55 and older rose to 10.5 million in 2008, from 1.5 million in 1987, making this group the fastest-growing segment of the health club population.

Does age matter?
This depends on the context. This is what is does in the gym: The music changes to the Beatles and the Beach Boys from the Black Eyed Peas, and the hi-tech designer spandex attire gives way to loose, comfortable pants and blouses. The conversation changes, too.

Exercise classes
In the gym where I go, the manager caters to the retired and semi-retired clients. He has laid out a special ‘retirees’ circuit of exercises on the 30-foot by 20-foot outdoor patio. The elastic resistance tubing, three-pound dumbbells, and stability and medicine balls may be sneered at by the body-building fraternity, but they are just right for these retired or semiretired clients.

What the gym offers the retired
As they begin their 30-minute regimen, the atmosphere at the club shifts. There is a lot of “do you remember…” conversation. These are familiar, comfortable, social groups who have come to exercise. The 8:30 class is for women and at 9:30 there is a stretching class for older men. Fitness clubs have changed their approach to deal with the older population. The older members have less rigid timetables and are likely to be found working out at all hours of the day. Classes are often geared for less-agile bodies or emphasize concepts like balance training, a skill that is particularly important for older adults.

The history of the gym
Many older Americans grew up in a culture of exercise, which started from the aerobics movement inspired by Dr. Kenneth Cooper in the 1960s to the weight-lifting craze after “Pumping Iron” in the 1970s and back to aerobics with Jane Fonda videos in the 1980s.

Doctors orders?
Whether they have been prodded by their physicians or spurred by research showing the many benefits of physical activity for older adults, people in their 50s and 60s are joining gyms and jolting the workout culture.