What could the government possibly be thinking, recommending 30 to 90 minutes of exercise a day? Who has time for that?

Couch potatoes see the recommendations, announced last week, as so unrealistic that there's no point in trying to follow them. Busy people with jobs and families are throwing up their hands in exasperation.

Time-use researchers and exercise experts say we're just making excuses.

"People certainly do have the time. There are about 40 hours a week of free time in this country," says John Robinson, a professor of sociology at the University of Maryland and co-author of Time for Life:The Surprising Way Americans Use Their Time. People are watching TV an average of 15 to 20 hours a week, so they have "room to carve out more time to be active."

JoAnn Manson, chief of preventive medicine at Harvard's Brigham and Women's Hospital in Boston and a leading researcher on the benefits of physical activity, says: "I'm convinced from the research that a sedentary lifestyle kills you, and moderate activity like walking can be lifesaving. A little exercise is better than none, but more is better than a little."

Revised Dietary Guidelines for Americans from the Health and Human Services and Agriculture departments, aimed at curbing the nation's growing weight problem, recommend adults do about 60 minutes of moderate to vigorous physical activity most days to prevent weight gain and 60 to 90 minutes of moderate daily activity for those trying to maintain weight loss.

They call for at least 30 minutes most days to reduce the risk of heart disease, type 2 diabetes, osteoporosis and other diseases. Earlier guidelines only had the 30-minute recommendation.

Government research shows that only one-third of adults make that 30-minute goal. So the chances that a sedentary population will rise as one from its recliner appear, well, slim.

And yet there is a hard reality to face: About 65% of Americans weigh too much.

Some recommendations might seem "intimidating, but they are based on science," says Russ Pate, a University of South Carolina professor of exercise science who was on the guidelines committee. And not everyone has to exercise at the highest level. If you figure out which activity level applies to you, it might not seem as daunting, he says.

"The baseline is 30 minutes. We all need that," he says. You can walk briskly, dance, play tag with the kids, pace while talking on the phone, shovel snow, shoot hoops, bike, swim or golf. The activity could be done in 10- and 15-minute segments as long as it adds up to 30 minutes or more.

If you're doing that much and are still gaining weight, you probably need to do more, Pate says, and for some people that will be as much as 60 minutes. Those who have lost a significant amount of weight and are trying to keep off the extra pounds might need as much as 90 minutes.

Many exercise avoiders argue that they don't have the time. Robinson buys this argument only for some people. The most time-crunched are people ages 30 to 45, parents of young children and people who work more than 40 hours a week, he says. For almost everyone else, leisure time is up significantly. Both men and women have gained about five hours of free time a week since 1965. Time-use experts suggest a few reasons: Some people are retiring earlier, some are working less, and some spend less time on housework.

Much of that time comes in small snatches, 15 minutes here, 30 minutes there, Robinson says. Most people are filling up that extra time with television.

From studying people's time-use diaries, he finds they watch TV or work or play on the computer three to four hours a day. About a third of the time they are doing other activities at the same time.

And despite some research to the contrary, Robinson says, people are more active, averaging two to three hours a week of exercise, mostly walking.

Pate agrees that it's hard for some folks but says most people can exercise if they make it a priority.

"Habitual exercisers" know when they're going to do some activity and are not just hoping it will happen, he says. They sort of "scan through their day in their minds in the morning" and figure out the best time to exercise. It may be at 6 a.m. before going to work, during their lunch hour, right after work or in the evening with a friend. "They're able to remain active because they make it a priority, and because they've learned to manage their behavior and their time."

Working it into real life

Karen Nickerson, 58, of Fairfax, Va., says she works out first thing in the morning. She lifts weights three days a week and jogs three days. "I can't piddle around and then go exercise. I've got to get up and do it, and then I'm done for the day."

Joan Pond Laisney, 57, of Carlsbad, Calif., says exercise has been key to her weight loss in the past 18 months. At 5-foot-8, she weighs 159 pounds, down from 204. She took USA TODAY's Weight-Loss Challenge (dietchallenge.usatoday.com). "I devote an hour a day to exercise. I don't let up. Nothing is going to take that away from me. If you want to do something bad enough, you'll find ways to make it happen."

The guidelines don't require doing 30 to 60 minutes of activity in structured exercise alone, which would be impractical for many people, says Manson, who is co-author of The 30-Minute Fitness Solution.

She recommends that people try to take a brisk walk for half an hour a day (or two 15-minute walks) and then try to accumulate the other 30 minutes by using the stairs whenever possible, getting up and taking regular short breaks from their desk, or walking around the mall or their home.

A brisk walk means walking with purpose, moving as if you're trying to get somewhere. You have slightly harder breathing, but you are easily able to talk.

Another way to reach the goal is to wear a step counter and try to accumulate 10,000 steps (about 5 miles) a day, Manson says. About 5,000 steps could be through a structured activity such as walking for 30 minutes, and the other 5,000 could come from moving more throughout the day

'Small changes' for starters

Manson says the 90-minute exercise suggestion probably applies mostly to highly motivated people who want to be in great shape, have a lot of weight to lose or are trying to maintain a large weight loss.

The higher goal is based, in part, on findings from the National Weight Control Registry, about 5,000 people who lost an average of 73 pounds and kept off at least 30 pounds for more than six years. They limit calories and walk about four miles a day.

Manson worries that the importance of strength training, which can be done in 15- to 20-minute intervals, two or three times a week, might get lost in the debate. She recommends that time-pressed people multitask by using the treadmill or doing weight training and other exercises while watching their favorite TV programs.

Not all of these changes have to be made overnight. "I would like to see us concentrate on getting people to make small increases in walking," says James Hill, an obesity researcher and a founder of America on the Move, an initiative to get people to walk an additional 2,000 steps a day or cut 100 calories (www.americaonthemove.org).

"If you start with small changes, many people can probably get to 60 minutes a day, but if you start by asking for 60 minutes a day, many people may not even try to be more active."