Take a Shortcut to Fitness With Circuit Training
Get strength and cardio benefits in 30 minutes a day
By Carol Sorgen
Reviewed By Kathleen Zelman, MPH, RD, LD
While her kids are at dance class, Elaine Magee goes two doors down to Curves gym and knocks out a 30-minute circuit-training workout designed to exercise every muscle in the body.
Actually, because she is a dancer and exercise devotee, Magee, -- better known as WebMD Weight Loss Clinic's "Recipe Doctor" -- is not the typical client of Curves. The 10-year-old franchise operation, which now owns one in four gyms in the United States, targets sweatsuit-wearing, overweight females in their 30s who may have never worked out before. There's little Spandex in sight. No juice bar. No hunks. And the workout? Simple. Just music, an array of circuit-training machines, and the command to "change stations."
With the popularity of Curves, circuit training has come into its own, although it's been around for decades. And though the Curves philosophy appeals to many, you don't have to join any particular gym to reap the time-saving fitness benefits of a circuit workout.
What Is Circuit Training?
Circuit training is short bursts of resistance exercise using moderate weights and frequent repetitions, followed quickly by another burst of exercise targeting a different muscle group.
Because the exerciser switches between muscle groups, no rest is needed between exercises. This gets the heart rate up, which usually doesn't happen during resistance exercise. Sometimes, to up heart rate further, aerobics are sprinkled between the resistance exercises.
"The stations are all set up with the right machines when I get to Curves," Magee says. "They are set to give more resistance the faster you go, so you don't have to adjust that. There are 15 machines. So you go on one machine for 30 seconds, and then jog on a pad for 30 seconds. Then you go on the next machine, and then jog. Once around [the machines] -- 15 minutes. We go twice around. Then you're done!"
A recording signals when to change machines or jog. Every 10 minutes, the exercisers check their heart rate.
"Ideally," says Wayne L. Westcott, PhD, fitness research director at the South Shore YMCA, in Quincy, Mass., "you get to 40% to 60% of maximum heart rate."
Why Circuit Training Works
"I am not there to lose weight, but to firm and tone," Magee says. "But I have noticed that my pants are looser."
Westcott cites the "classic" Cooper Clinic study done in 1982, which studied the effects of doing a circuit workout three times a week. The study had 77 participants, who were divided into three groups.
"One group did not train at all," Westcott says. "One group just did the weights. And the third group jogged in between the weight sessions."
Not surprisingly, the group that didn't train saw no improvement in its cardiovascular fitness. The weights group improved cardio fitness by 12%. And the weights-and-jogging group improved 17%. (The weights group also improved strength by 17% and the weights-and-jogging group improved strength by 22%.)
According to Westcott, a circuit workout improves both strength and endurance, and jump-starts metabolism.
"When those women leave the gym, they are still burning a third more calories than they did in the workout -- and this goes on for hours!" he says. "Once you build muscle, muscle burns more calories [than fat], so you continue to burn more."
Although weight training has traditionally been a male pastime (think Ah-nold), it's important for women, who tend to lose muscle mass at the rate of 1% per year in their late 30s and 40s. This muscle often gets replaced by fat. But you need muscles to cushion joints and help protect against osteoporosis, among other benefits. That's not to mention the trimmer, tighter appearance you'll gain by toning up.
Circuit training works because it's short and sweet and people actually do it. (Many gyms, as well as a chain called Health Inspirations, offer circuit training to both sexes.) "It's brief, it's basic, it's consistent; no frills, over quickly" is how Westcott puts it.
Is Circuit Training Enough?
But is a 30-minute workout enough? "I hate that question," says Cedric X. Bryant, PhD, chief exercise physiologist of the American Council on Exercise in San Diego. "Speaking purely scientifically, 30 minutes is probably not enough to maintain normal weight over a lifetime."
The Institute of Medicine recently recommended an hour of exercise a day.
"However," Bryant continues, "this [circuit] is often done by people who weren't exercising before." And he sees why many people are drawn to Curves in particular. "The environment is conducive to comfort -- there is no intimidation factor," he says. "You are not surrounded by so-called beautiful people and figure you're so far from the norm, why bother?"