How hard is hard?
So how strenuous should exercise be? How long is the ideal exercise session? And how many minutes of exercise should we strive for each week?
This is still the subject of intense debate. But two new studies should help provide better guidelines. Advocates of exercise lite have long argued that you can piece together 3 or 4 shorter sessions of 10 or 15 minutes of activity and get the same benefits as a sustained hour workout -- and it seems they're right. In a study published in the September issue of Circulation, researchers surveyed more than 7,000 men. Those who said they typically worked out in several short sessions of about 15 minutes were assessed as being just as healthy as those who did their exercise in one long session.
What appeared to matter, the study found, was how vigorously people exercised and the total amount of time they spent doing it. Therefore, anyone who wants to lower his or her risk of heart disease may need to fulfill the surgeon general's recommendation of exercising a minimum of 30 minutes at moderate intensity for at least four days of the week, in any cumulative combination.
Pick up the pace
If you're a lounge lizard whose idea of exercise is picking up the remote control, then walking a little every day will make you healthier and increase your odds of living a long life. But don't think you can shuffle along and call it exercise.
"When we say brisk, we mean brisk," says Andrea Dunn, her arms pumping as she powers her way down the corridor as I hurry alongside to keep up. "We're talking about walking fast enough to cover at least three and a half miles an hour. A brisk walk is the way you'd walk if you were hurrying to catch a bus or to get in from the cold. It's walking fast enough so that you begin to feel winded."
If walking is your exercise of choice, Dunn recommends mapping out a one-mile course. (You can drive the route in your car using the odometer or walk around a track at the local high school.) Then clock yourself while walking one mile. If you cover the distance in 15 minutes or less, you're walking briskly. "Believe me, we're not talking about strolling down the boulevard," says Dunn, sounding just a tad winded herself. "And we're not talking about stopping to smell the roses."
Peter Jaret, a freelance writer based in Petaluma, Calif., has written for Health, Hippocrates, and many other national publications. He is a contributing editor for WebMD.