QUEBEC CITY -- Physical inactivity, more than obesity, is to blame for a large chunk of America's battle with chronic illness, according to Dr. Steven N. Blair president and CEO of the Cooper Institute, a nonprofit research and education center in Dallas, which focuses on the relationship between living habits and health.
"One of my biggest frustrations is that physicians will so often tell their patients to lose weight, but so few of them will say 'Get fit.' And yet research shows that obese individuals who are fit have half the death rate of lean individuals who are inactive," he said at the annual meeting of the American Orthopaedic Society for Sports Medicine.
"I am not saying we should ignore obesity, but we need to recognize that physical inactivity is one of the major public health problems of our time," he told this newspaper. But remedying poor physical fitness will probably do more for a patient's health than simple weight loss.
In a recently published study, Cooper Institute researchers reported that in a group of more than 2,000 men with diabetes, obese, but moderately fit, men had one-third the death rate of normal weight but unfit men (Diabetes Care 27[1]:83-88, 2004). The men were divided into four quartiles according to fitness, then classified as either normal weight, overweight, or obese, according to body mass index (BMI). Risk of mortality was then calculated based on the 275 deaths that occurred over the course of the 25-year follow-up.
The researchers found that BMI was not a significant factor in mortality risk, but physical fitness was. For example, the risk of mortality was 4.5, 2.8, and 1.6 times higher for the lowest, second, and third fitness quartiles, respectively, when compared with the highest fitness quartile-and these risks were independent of BMI.
"For a 45-year-old man in this study, moderate fitness, as opposed to low fitness, means he will live 6 years longer, and attaining a high fitness level would mean he would live 9 years longer," he said.
Another recent study from the Cooper Institute suggests that physicians also can promote physical fitness as a "fountain of youth" (Am. J. Health Promot. 15[1]:1-8, 2000).
"We found that fit men over the age of 80 were healthier and had more function than unfit men who were 2 decades younger," Dr. Blair said.
And in two additional recent Cooper studies, researchers reported that cardiorespiratory fitness provides strong protection against mortality in men with metabolic syndrome, and seems to ameliorate some of the symptoms of metabolic syndrome in women.
The first study followed almost 20,000 men, 80% of whom were healthy, and 20% of whom had metabolic syndrome, for 10 years. Compared with the healthy subjects, men with metabolic syndrome had almost twice the risk of dying from cardiovascular disease and 1.3 times the risk of dying from other causes. But if they were fit, their risks were similar to those of healthy men (Arch. Intern. Med. 164[10]:1092-97, 2004).
In the second study of more than 7,000 women, the prevalence of metabolic syndrome decreased with increasing levels of cardiorespiratory fitness, suggesting that because regular physical activity improves components of the metabolic syndrome, improving fitness levels may, in some cases, ameliorate the disorder (Obes. Res. 12[5]:824-30, 2004).
Dr. Blair said patients should be encouraged to "just take a walk, that's all we're talking about here," and not get hung up about the risks of starting an exercise program.
In general, even obese patients can exercise safely, Dr. Blair said. "We do not see an increase in knee osteoarthritis in people with BMIs of over 30 who exercise, compared with the nonexercisers. A high BMI by itself is a risk factor for knee osteoarthritis, and that's thought to be due to mechanical wear and tear.... Being overweight is not a reason to avoid exercise."
Current public health recommendations advise that all adults should have 30 minutes of exercise per day, and this can be as light as three 10-minute walks.
Although a 30-minute walk is good, research suggests that the more strenuous the exercise, the greater the benefit. Another study from his institution suggests that muscular fitness should be considered important, independent of aerobic fitness, he added (J. Physical Activity Health 1[1]:7-18, 2004).
To determine a protective level of fitness. Cooper Institute researchers followed more than 17,000 walkers, joggers, and aerobics class participants, all of whom were classified as moderately fit, to see what level of activity maintained their fitness levels. The walkers logged between 130 and 150 minutes of exercise per week, the joggers logged around 90 minutes per week, and the aerobics class participants logged between 100 and 130 minutes per week (Am. J. Public Health 88[12]:1807-13, 1998).
"This is not heavy duty activity and it is consistent with current recommendations," said Dr. Blair, who proudly displayed a rather portly waistline. "Can you be fit and fat?" he asked, opening his jacket. "I run 26 miles a week."
BY KATE JOHNSON
Montreal Bureau
COPYRIGHT 2004 International Medical News Group
COPYRIGHT 2004 Gale Group
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