It is not only sedentary men who are finding that the pants they wore comfortably at 40 are hard to button at 50.
Middle-age spread seems to be a near-inevitable consequence of advancing age, even among men who regularly run long distances. A study of nearly 7,000 male runners 18 years old and older has shown that even those who run long distances and maintain their youthful level of exercise can expect to accumulate abdominal fat when they reach middle age.And since flab around the waist is associated with changes in body physiology that increase the risk of heart disease, even physically active men should be concerned about their expanding girth, said the researcher, Dr. Paul T. Williams, an epidemiologist at the Lawrence Berkeley National Laboratory in Berkeley, Calif.
Although the runners in the study were typically leaner than their sedentary counterparts, and longer-distance runners were slimmer than those who ran short distances, for men from 18 to 50, weight gain occurred at the same rate regardless of the number of miles they ran each week, Williams reports in The current issue of the American Journal of Clinical Nutrition.
"We aren't seeing a big difference in the rate of gain between those who run fewer than 10 miles a week and those who run more than 40 miles a week," Williams said in an interview. For each decade, the average 6-foot-tall man put on 3.3 pounds, and his waist grew by about three-fourths of an inch. In other words, by 50 a physically active man can expect to weigh about 10 pounds more and to have a waist about two inches bigger than he had at 20.
Is liposuction the only answer? Not necessarily. Williams suggested that to compensate for the metabolic changes that result in expanding girth with age, physical activity should be gradually increased each year, starting at around 30.
For example, Williams calculated, an annual increase in weekly running distance of 1.4 miles should make up for the age-related decreases in metabolic rate and permit a 50- or 60-year-old man to fit into the tuxedo he wore to his wedding at 30. In other words, a man who ran an average of 10 miles a week at 30 should, by the age of 40, be running 24 miles a week and, by the age of 50, 38 miles a week to maintain his youthful physique. Of course, knees and ankles and backs may be starting to weaken at the same time that Williams is arguing for more, not less exercise.
Running is not the only way to ward off middle-aged spread, Williams said in an interview. "Any sustained, vigorous activity will do, including swimming laps, cycling and working out in a gym, as long as the workout is sustained and vigorous," he said. Another approach would be to eat less, while making more nutritious food selections.
As for why these changes in physique occur, Williams suggested that age-related declines in the production of testosterone and growth hormone might account for the gradual accumulation of body fat. He noted that injections of testosterone tended to reduce the waistlines of middle-aged men and that a similar loss of abdominal fat occurred in men given growth hormone.
Williams is now looking into patterns of weight gain in women who are runners. Before menopause, he noted, women tend to gain fat around their hips and thighs rather than their waists. But after menopause, when estrogen levels drop precipitously, women tend to switch to a male pattern of weight gain, accumulating fat around the abdomen. What effect hormone replacement has on this pattern has not yet been well studied, he said.
Based on his studies of men, Williams took issue with the current Government advice about weight and exercise patterns at different ages. The current standard sets the same standards for overweight for young and old alike and recommends that people maintain their level of physical activity as they get older.
"These are inherently contradictory," Williams said.