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January 02, 2008 | 7,006 views

Losing weight and keeping it off may require more exercise than previously thought -- maybe twice as much as the 30 minutes recommended. A study from Brown University researchers found that 2,500 people who lost an average 60 pounds and kept it off for a year exercised about an hour a day. We know that 30 minutes every day is a good thing -- it's better than less than that. But after that, what you want is somewhere between 30 and 60 minutes.

Most of the people studied walked about 10 miles a week, and then did aerobics, weight lifting or other activities. Another study found that short bouts of exercise during the day were as effective as one long period in maintaining weight loss for women. It is important that people know they can exercise a little bit at a time. To send them a message they have to do an hour a day is going to turn them off. We need to readjust that figure and find ways to get people to do a little more. Patients who kept the weight off likely paid close attention to their diets as well. If you don?t adopt both exercise and focus on the eating behaviors you won?t be successful long term.

Annual Meeting of the North American Association for the Study of Obesity at Charleston, South Carolina November, 1999

Dr. Mercola's Comment:

It is not common that a news piece changes my clinical practice, but this report has. I will be confidently advising patients who are heavy and seeking to lose weight to increase their exercise to one hour per day. This will require significant lifestyle modifications, as most of us do not have a free hour to spare every day.

One simple suggestion, in light of the fact that winter is approaching and walking outside is not really a comfortable option for most of us, is to use a high quality rebounder. One needs to purchase one for at least $200 as the $20 models will not hold up. I recommend 800-497-9516 as the least expensive source I have been able to identify.

When I had TV in my home, I would watch it while I was rebounding in the winter and found it a practical way to be more efficient and get in my exercise. I was delighted to find out from this report though that exercise can be broken up and the same benefits will be achieved. This makes compliance much more likely to this approach.

Let?s say you?re already a fan of fitness. You?re tuned into the diet and exercise regimen your body needs to keep on ticking properly.  But like a lot of Americans, you?d like to lose a few more pounds and your days are already packed. You squeeze in a half-hour of exercise over lunch (if you don?t have a meeting) or after work (if you can break away before you need to get to your dinner date or home to the kids). You've been reading for years that you should shoot for 30 minutes of exercise a day, and that?s all you have to give.

Then along comes last week?s report that researchers now think you might need to double your exercise time to an hour if you want to lose weight and keep it off. It?s enough to make you give up, head for the couch and get ready for a nice cozy winter of chips ?n? salsa ?n? channel surfing.

But if you probe behind the breathless wire stories and talk to the Ph.D.?s of the fitness world ? as we did for this story ? you realize that all is not lost. Experts say many people focus too much on the duration of their exercise time and not enough on the intensity. Thirty minutes a day can still be enough if you concentrate on ramping up your routine when you?re ready.

Double Your Pleasure?

John Jakicic, an assistant professor at Brown University School of Medicine who studies exercise and obesity, was part of the team that presented their findings at last week?s symposium of the North American Association for the Study of Obesity.

How Much Should You Do? 

National Coalition to Promote Physical Activity (US Surgeon General, CDC, AHA, et al): 30 mins moderate 5 or more days

Jakicic seminar: 60 mins moderate 5 or more days

American Coll. Sports Medicine: 20 mins mod. -High 4-5 days

These are the MINIMUM exercise recommendations of various experts. The National Coalition offers a broad guideline, Jakicic focuses on people who exercise primarily to lose weight, and the ACSM focuses on people who are already in a safe weight range and exercise primarily for health and fitness. All groups say if you have time for an hour a day, go for it.

The Brown group studied data from an established survey of overweight people known as the National Weight Control Registry, as well as several of their own studies funded by the National Institutes of Health. They looked at the histories of a group of overweight women, all of whom were age 18 or older and had lost 25 pounds or more. The average starting weight of the group was 200 pounds, and their principal fitness goal was weight loss. Then the researchers looked at the individuals who had been most successful ? those who had maintained their 25+ pound weight loss for a year or more.

And they concluded that for those women, the U.S. Public Health guidelines on exercise for general cardio-respiratory fitness were just not enough. Those guidelines suggest that Americans should exercise at moderate intensity (activities like brisk walking) for at least 150 minutes a week: a half-hour a day five or more days a week.  But when weight loss, not heart and lung health, was the main objective, the most successful individuals had exercised for 280-300 minutes a week at moderate or higher intensity, according to Jakicic. ?Doing just the amount of exercise indicated by the public health guidelines doesn?t do enough for weight loss,? he says.

Burn It Up

But Wayne Westcott, fitness research director at South Shore YMCA in Quincy, Mass., says that the hour-a-week suggestion only tells half the story. ?People concentrate too much on the time they exercise instead of on the effort they expend,? says Westcott. ?In reality, you need both ? it?s a reciprocal relationship.?   To illustrate, he uses an example of a non-overweight person exercising with her dog. If she walks her dog for an hour at a brisk 4mph pace, she burns 400 kcal (calories). But if she doubles the pace to an 8mph running speed and goes for half the time, 30 minutes (not easy but a speed most runners can build up to), she burns about 440 calories, 10 percent more.

?It?s like what you always hear about your car,? says Westcott. ?If you rush to get to the gas station, you actually burn more fuel.? Even when you?re on foot, covering the same distance at a faster pace burns more calories.  This fact is especially relevant to people who do some of their exercise in gyms on cardio equipment like treadmills, stairclimbers and stationary bikes. Those machines often have two programs: a faster one called something like the ?conditioning zone,? and a slower one like the ?fat-burning zone.?

But the reality is that most people only get on those machines for a fixed amount of time every workout, say 20 or 30 minutes, regardless of how fast they plan to go, and many of them purposely keep their speed down because they think they?re burning more fat. Wrong! ? Westcott contends that the faster you go, the more calories of fat you burn, no matter how high you jack up your speed.  ?There?s no difference between ?weight-loss? people and ?fitness? people in the exercise world. My recommendation to both groups would be: If you can afford 60 minutes a day, great. If you can?t, or if you?re just getting started, work up to 30 minutes, then increase the intensity.?

Do What You Can

With enough motivation people can lose weight on their own. Half of the people in the Registry didn?t have the help of dietitians or commercial weight-loss programs or self-help seminars. They did it by getting off the couch and making sure they set aside the time to exercise, even if they had to do it for twice as long as other people. And the root cause of what Jakicic?s data show may be this: high-intensity conditioning is often too much for obese people to handle, and therefore they have to put in more time. At a certain point, admits Jakicic, ?we need to balance what we think they need to do and what we can actually get them to do.?  So don?t give up on exercise completely just because you don?t have an hour a day to give. But if you can?t do the time, you?d better be ready to sweat.

Not So Easy

Researcher Wayne Westcott dismisses the common belief that training at lesser intensity burns more fat than training at higher intensity. The percentage of fat calories burned is higher at lower speeds, but the absolute number of fat calories burned is always greater at higher speeds ? and for people trying to lose weight the total number is the only thing that matters. 

A recent study compared calorie burn rates for a 30-minute walk at 3 1/2 mph (moderate walking speed) and a 30-minute run at 7 mph (moderate running speed). The walking group burned an average of 240 calories in their half-hour, 40 percent of which came from fat and 60 percent of which came from carbohydrates. So the walkers burned 96 calories of fat. Now, the harder-exercising runners split their calories differently: 24 percent of their burn comes from fat, 76 percent from carbs. But they burned a whopping 450 calories in the same half-hour, which means they burned 108 calories of fat in the same amount of time.

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