An Exercise in Common Sense : Health: You don’t have to knock yourself out at the gym to live longer. A new study says moderate exercise is enough.
“Face it. There are millions of people out there for whom the exercise prescription should be get up off your butt and take a walk. Get out the door. Do something. “
If researcher Steven N. Blair sounds frustrated when he gives this earthy assessment of America’s physical fitness, it’s because he is.
Americans largely have ignored more than two decades of advice that they sweat their way into tiptop cardiovascular shape, the Dallas epidemiologist says, so it’s time to give them a new message: A little bit of exercise is good enough.
And Blair really means it. With a recent study at Dallas’ Institute for Aerobics Research as a guide, he has developed what he thinks is the bare minimum a person has to do to vastly reduce the risk of dying prematurely--and it isn’t all that much.
No, you don’t have to get up daily at the crack of dawn to huff and puff through the streets. No, you don’t have to find a baby-sitter available for just one hour a day, seven days a week.
A brisk two-mile walk three times a week is all it takes, Blair says. For men, the two miles should be covered in 27 minutes or less; for women, 30 minutes or less.
If you can’t walk at that 3- to 4-m.p.h. pace at first, you can take up to 40 minutes in the beginning--but women would have to do it five to six days a week and men six or seven days a week.
Judged by the “aerobic points” system, which classifies exercise based on how much oxygen it causes one to use, that amounts to a minimum of 15 aerobic points a week for women, and 18 aerobic points a week for men. Other exercise adding up to that total amount could be substituted for the walking, he noted. (People under 50 need a bit more exercise than the minimum, and people over 50 can get by with a bit less.)
“It doesn’t make any difference what you do, as long as you expend the energy,” Blair said.
But that’s about half as much exercise as has been advocated for the last two decades by Dr. Kenneth Cooper, the fitness guru who coined the term aerobics back in 1968. Cooper founded the Cooper Clinic and the aerobics institute where Blair does his research.
Cooper, who co-authored the recent study on which Blair bases his recommendations, agrees that it’s time to emphasize that people don’t have to train like Florence Griffith-Joyner to gain the health benefits of exercise.
This new exercise prescription for the masses “doesn’t even look like a routine physical conditioning program. All it really is is avoiding inactivity,” Cooper says.
“I think there are at least 30 million Americans out there who are dying younger than they need to just because they’re totally inactive,” he said. “They say, ‘I’m not an athlete, I don’t have time, I don’t have the money.’
“Well, we’ve eliminated those excuses now. Because you don’t have to join a health club, you don’t have to buy expensive equipment, you don’t have to have a friend or partner to play with you,” Cooper said.
In a November paper based on data collected at the Cooper Clinic, researchers showed that the largest difference in mortality--about 60%--was between the sedentary and people who were only moderately fit, as judged by performance on treadmill exercise tests.
Over an 11-year period, the sedentary men had an overall death rate of 64 per 10,000 person-years of participation in the study. The moderately fit had a death rate of 26 per 10,000 person-years. Among women, the mortality rate fell from 40 to 16.
This translates into one to three extra years of life for the moderately fit, Blair said.
Furthermore, improving one’s fitness beyond this moderate level did decrease mortality, but not by much. The high-fitness group had death rates of 20 per 10,000 person-years for men and seven per 10,000 for women.
In other words, especially if you’re a man, you don’t have to become an exercise fanatic to gain most of the death-postponing benefits of exercise.
To quantify the exercise needed, Blair compared the study’s findings to the exercise records kept on people who work out at an aerobics center affiliated with the Cooper Clinic. How much weekly exercising did it take for those people to have treadmill times classifying them as “moderately fit” by the study’s standards, he asked. The result was the recommendations.
A survey last year by the U.S. Centers for Disease Control found that only 8% of Americans get as much exercise as government health officials recommend.
That recommendation basically is that healthy adults should spend 15 to 25 minutes a day, three to four days a week, doing some form of exercise vigorous enough to elevate breathing and heart rates but not so vigorous that it becomes impossible to talk comfortably.
(The American College of Sports Medicine recommends exercise sessions of 15 to 60 minutes, three to five days a week.)
The survey found another 34% of adults were “regularly active,” which the CDC defined as doing some kind of physical activity at least three times a week for a minimum of 20 minutes each time.
If that 34% exercised a bit more, and other Americans could be coaxed off their living room couches, there would be less fat, more muscle and fewer early deaths, Blair says.
Such advice is of particular importance for California’s burgeoning Latino population. Government surveys show obesity--which is a factor in many chronic diseases--to be higher among Latinos than other ethnic groups.
Among Latino middle school students in the Montebello School District, 51% of girls and 41% of boys had body fat composition in the high or very high level, a study by Cal Poly Pomona researchers found.
The National Hispanic Health and Nutrition Survey found that among Mexican-American adults, 39% of women and 31% of men are overweight. Nearly half of those women and a third of those men are severely overweight.
For the average American, the modified Cooper Clinic exercise prescription in essence promotes the idea of a new category of physical fitness--one beyond the high-fitness image that advertising gives.
Ads imply that the only exercise is the extremely vigorous kind, and that it is the sole province of the young, the beautiful and the physically gifted, Blair said.
“These people don’t look like most of us look. We’re not all young and lean and attractive,” Blair says as he laughingly points to his own balding head and chunky physique. “My mother looks at those ads and she says, ‘Well, I can never look like that. I’m too old and fat and therefore to heck with it. I’m one of the slobs.’ ”
There is “a dichotomous view of exercise in the mind of the American public,” Blair says. “You’re either Jane Fonda, a marathon runner, a triathlete or you’re a slob--when, in fact, this is a continuum.”
For people who have trouble sticking with an exercise program, science has more good news: There are hints that both sporadic exercise and shorter bouts of it are like a “good-health pill” for the body.
Biochemical changes from just a few exercise sessions include greater insulin sensitivity of cells, resulting in better carbohydrate metabolism, and lower levels of fat-carrying triglycerides in the blood, said William Haskell, associate professor of medicine at Stanford University.
And as the exercise prescription moves toward being more real, so are the activities that one can use to fill it.
A 1987 study at the University of Minnesota found that men who got an average of 47 minutes a day of exercise--mainly by mowing the lawn, gardening and working around the house--had markedly fewer heart attack deaths than did sedentary men. And, as in the Blair research, mortality didn’t improve much beyond that in men of higher fitness levels.
Furthermore, although a rule of thumb in the past has been that one needs to expend at least 2,000 calories weekly on vigorous, sustained exercise to gain cardiovascular benefit, these men averaged about 1,500 calories a week on activities that amounted mainly to puttering around the house.
Gail Weldon, a Los Angeles athletic trainer who specializes in fitness training for individuals, said she agrees with the Blair/Cooper push to move Americans away from thinking of themselves as exercise nobodies if they aren’t running marathons regularly.
However, people looking for a personal fitness prescription should keep in mind the need for flexibility and gradual muscle strengthening, she said.
“Obviously we have to have the heart and lungs working well to increase our longevity, but I work on so many of the musculoskeletal pains that I also emphasize that you need to have some flexibility in the muscles to support the structures around them,” Weldon said.
Regular stretching and mild weight training can address those issues and even improve balance in the elderly, she said.
The Institute for Aerobics Research recently was funded by the National Institute on Aging to continue its studies of exercise and fitness, this time trying to determine the relationship between regular exercise and chronic illnesses and disability. The results of the five-year study could be more important than looking at mortality, Blair suggested.
“I would much rather run out of life than run out of function,” Blair said. “And if you ask your parents, your grandparents, what do they fear. It’s not dying, it’s those two words: nursing home. Our hypothesis is that some--we have no idea how much--of the disability that we see in older individuals is a result of sedentary living.”
NEW Rx FOR EXERCISE
The aerobic points system classifies exercise based on how much oxygen it causes one to use. Younger people probably need to do a little more exercise, and older people a little less.
MEN
Aerobic points: 18-36. Minimum activity needed: Walk two miles in less than 27 minutes at least three days per week. Or walk two miles in 30-40 minutes, six to seven days per week.
WOMEN
Aerobic points: 15-24. Minimum activity needed: Walk two miles in less than 30 minutes at least three days per week. Or walk two miles in 30-40 minutes five to six days per week.
Source: Steven N. Blair, Institute for Aerobics Research.
