The Rise and Fall of the Fitness Generation

Intense media interest helped all these trends spread quickly, says Len Kravitz, an exercise researcher at the University of New Mexico. "Coverage of people who were combining dance, music and exercise — like Jacki Sorensen, Jane Fonda and Richard Simmons — really fueled the public's interest."

And then came what Kravitz says was the real game changer: the exercise video, led by Fonda's famous leg-warmer "feel the burn" moves. "It meant people didn't have to go to a class or join a club," he explains. "It really changed the fitness landscape."

By 1987 — the apex of the golden age of our abdominals — 69 percent of American adults were regular exercisers. Many boomers pursued fitness careers, becoming personal trainers. Others harnessed their workouts to change the world, with groundbreaking AIDS bike rides and breast cancer walks raising millions for worthy causes.

Then something strange happened. Boomers, once the peppiest generation, devolved from fit to flabby. Don't take my word for it. JAMA Internal Medicine recently revealed that boomers are far less fit than their parents were at the same age and are more likely to have diabetes or high blood pressure. Today just 35 percent of boomers exercise regularly; 52 percent have no routine.

What happened? Some blame our fast-food nation with its supersize portions. Kravitz points to the growth of personal technology, which encourages sitting and fiddling with small devices. "Exercise takes effort and time and energy," he says. "In our society we can work, play, entertain and communicate — all while sitting in the same chair."

Naturally, boomers think they're more active than they are. A new study in Medicine & Science in Sports & Exercise finds that people overestimate the amount of exercise they do by almost an hour a week, while underestimating the amount of time they spend sitting by almost two hours a week.

And then there are those irrefutable outcomes of middle age. "In 1990 the first wave of boomers were moving solidly into their 40s," says Smith. "That's a time in life when most people are really busy — with kids, careers, financial obligations, maybe even with aging parents."

And, of course, our own bodies were — and are — aging. Metabolism slows; muscles atrophy. Stuff happens. Knee-replacement surgery has doubled in the past decade, and tripled in the 45-to-64 age group, because of rising rates of obesity and some boomers' unwillingness to give up on their favorite exercise routines. "It's a big adjustment to realize you can't work out like you used to," says Cedric X. Bryant, chief science officer of the American Council on Exercise. No kidding. Easing back into a routine with simple walking and a few push-ups seems so … lame.

And while many boomers will likely find their way back to fitness under a doctor's orders, what we really need to do is rediscover one of the first tenets of fitness — what millions of us learned from Hula-Hoops, roller skates and Solid Gold: It's supposed to be fun. We don't need the surgeon general to tell us what we already learned from James Brown: "Get up offa that thing," sang the late, great Godfather of Soul. "And dance till you feel better."