Burst Into Shape

Short on time or not, quick bouts of exercise look like the way to go

DON'T HAVE TIME to exercise, huh? Well, just hurry up. Go faster. Go harder.

That message is coming louder and more often as the time vise tightens.

In just the past few months I've stumbled across: "Daily Quickies: 10 Minute Workouts" and the "5-Minute Cave Man Workout," which must be twice as good as the 10-minute one. A women's magazine hypes "Yoga a-Go-Go," which takes just five minutes. Another plan takes a laborious 15 minutes. A recent book, "Fit in 15," describes routines to reach "full fitness" through short, daily workouts. I tried to rev up with some magazine's "6 Moves in 6 Minutes" plan. After those, I practically yawned while slogging through the "Furman Total Fitness 30 (minutes)."

The usual advice is to try to get as much as 30 minutes of exercise a day, but there is growing evidence that those 30 minutes don't have to come all at once. Short bouts or bursts of activity are not only efficient but also smart, according to several studies.

Researchers at McMaster University say six minutes of intense exercise a week can be equal to an hour of daily moderate activity. Such bouts "improved muscle health and performance comparable to several weeks of traditional endurance training," says Martin Gibala, an associate professor in the department of kinesiology at McMaster.

The research, published in the Journal of Applied Physiology, found that performing repeated bouts of "sprint" exercises made profound changes in skeletal muscle and endurance capacity, similar to training that requires hours of exercise each week. The endurance capacity in the sprint group increased on average from 26 to 51 minutes, and the subjects' muscles showed a significant increase in citrate synthase, an enzyme that is indicative of the tissue's ability to use oxygen.

Researchers at Southwest Missouri State University and the University of Missouri found that accumulated 10-minute bursts totaling 30 minutes are more effective than continuous exercise in lowering fat and triglyceride levels in the bloodstream after eating. The study found that regular repetition of short exercise bouts can have a positive effect on metabolism. Researchers emphasized the results only apply to those participating in regular exercise.

"People who cannot exercise for long durations due to low fitness levels or busy lifestyles don't have to sit still and wait for a heart attack," said Thomas Altena, one of the study authors. "If we can encourage people to be active and accumulate at least 30 minutes of exercise in 10-minute bouts each day, it will have a positive effect on health overall, and more specifically, on the amount of fat in the bloodstream."

CrossFit North, a Sand Point health club, incorporates a series of short but high-intensity bouts into comprehensive, ever-changing programs. A participant may run a fast 400 meters, swing weights or a kettlebell over his or her head and do pull-ups. The intensity and actual exercises vary with a person's condition. Functionality, variety and focus are the key buzzwords.

CrossFit trainer Nick Nibler says the traditional way of doing the same exercises in the same pattern for several weeks or months produces diminishing returns as you go because your body gets used to what's being asked of it. That's what his program seeks to avoid.

Short, focused workouts that produce results and save time can help people stick with their programs. Curves For Women and the X-Gym, two establishments that get people in and out the door, seem to be thriving. Just be sure to factor in your condition — including a health condition — before going all-out. Build your fitness base up enough that your body can handle a good taxing, and stay within your limits.

Richard Seven is a Pacific Northwest magazine staff writer. He can be reached at rseven@seattletimes.com. Thomas James Hurst is a Seattle Times staff photographer.