Fitness, Not Weight, Could Be the Key to Good Health
If Americans would just do more exercise, they wouldn’t have to worry so much about how much weight they carry, a leading researcher says.
Being unfit and being fat bring independent risks of dying early, so a fat person can reduce some of the risk simply by exercising regularly, said Steven N. Blair of The Cooper Institute for Aerobics Research in Dallas. In this scenario, weight loss could be considered a separate benefit.
“As a public health problem, data from this report indicate that low fitness is perhaps the most important for obese individuals,” Blair said. “The low-fit men were just as likely to die as men who’d had a heart attack, a stroke, or some other form of cardiovascular disease,” Blair said.
Blair and his colleagues looked at data on 25,174 men who were followed for an average of 10 years. All were given exercise tests to determine their fitness. Thirteen percent were obese, 46% were overweight and 41% were of normal weight. About 50% of the obese men had low fitness.
The findings appear in a recent issue of the Journal of the American Medical Assn.
Obese men with low fitness had 2.3 times the risk of dying compared with obese men who were not unfit. In contrast, obese men who started the study with cardiovascular disease had 2.4 times the risk of dying, compared with similar men who started the study without it.
Obese men who had high cholesterol had a 70% greater risk of dying than did similar men without high cholesterol. Obese men with diabetes or who were current smokers had 50% greater risks, and obese men with high blood pressure had a 10% greater risk.
“Even I, with my biases, was a little surprised to see that low fitness was actually a stronger predictor of mortality than was diabetes, high blood pressure, high cholesterol or current smoking,” said Blair, a longtime proponent of the health value of regular physical activity.
And because low fitness is far more common than, for instance, diabetes, physical activity could have an even greater importance in saving lives, Blair said. Up to 44% of deaths among the obese could have been prevented by exercise, compared with 9% of deaths if diabetes had been prevented, he said.
To Blair, America’s preoccupation with the mirror and scale is misplaced. “For many of us, no amount of dieting or exercise will make us have the physique of models and movie stars,” he said. “It’s an unattainable goal.”
Losing weight can be a good thing, Blair said. But fat people can improve their health by exercising, even if they don’t become thin--and exercise is an attainable goal. “Thirty years ago, I was short, fat and bald,” he said. “Today, I am short, fat and bald. But I have run 100,000 kilometers [62,500 miles] in the last 30 years.”
Blair’s advice to doctors is to check their obese patients’ exercise habits as scrupulously as they check for signs of high blood pressure, high cholesterol and diabetes.
The article on exercise appeared in a JAMA theme issue that focused on obesity. Also in the issue was a report by the federal Centers for Disease Control and Prevention which found that obesity had risen from 12% of adults in 1991 to almost 18% in 1998. CDC researchers characterized this as an obesity epidemic.
A separate report, led by researchers at St Luke’s-Roosevelt Hospital Center in New York City, estimated deaths attributable to obesity at 280,000 or more a year. Obesity has been linked to conditions ranging from heart disease to diabetes.
Obesity and lack of exercise can be considered independent risk factors for an early death, said researcher David B. Allison of St. Luke’s-Roosevelt Hospital Center. So, although Blair is correct in pointing out that exercise is good, losing weight is also good--and doing both may be best, he said.
“Most things in human life, including death, are multifactorial,” Allison said. “It’s quite clear to me that obesity is a contributing factor. I also believe, from my reading of Steve’s other papers, that fitness is a contributing factor. But I don’t see these as exclusive.”
Fat people should look for the risk-reduction method that works for them, said Dr. George L. Blackburn of Harvard Medical School, who is president of the North American Assn. for the Study of Obesity.
“Behavior science teaches us that success is what we believe in,” Blackburn said. If a person believes in the value of diet, then diet is the method to try. A person who wants to rely on exercise should exercise, he said.
However, a combination of some vigorous exercise and some dieting may work best, Blackburn said. “Just 200 less calories a day would be 20 pounds lighter over a year,” he said. “Half you could cut back [in eating] and the other half you could burn in exercise.”
