Americans are growing fatter, and obesity is blamed for a broad range of health problems. But research is building a case that getting moving may be more important than losing weight.
A new study from the University of South Carolina's Arnold School of Public Health suggests physical fitness trumps body weight in reducing one's risk of death. Reported in Circulation, the Journal of the American Heart Association, the long-term study of 14,345 adult men offers good news for people who are physically active but can't seem to lose weight, said Duck-chul Lee, the study's lead researcher.
“You can worry less about your weight as long as you continue to maintain or increase your fitness levels,” said Lee, a physical activity epidemiologist at the South Carolina school.
The concept of “fit fat” is something Julie Downing, the physiology lab director at Central Oregon Community College, has been talking about for a while.
“It's way more important, and reduces risk so much, to be active and fit as opposed to thin and unfit,” she said. “Everyone knows it's unhealthy to be overweight and unfit. A lot of people think thin and unfit is next best, but actually no, it's healthier to be a little overweight and fit as a second (best) category.”
“Fit” doesn't have to mean that you can do the whole Pole Pedal Paddle by yourself, she said. Moderate fitness is fine, and that means just being active on a regular basis.
“Fitness to me means you're active enough that when you exercise it feels comfortable. It's enjoyable,” she said. “You can get out and hike a beautiful trail in Bend and not be winded, or climb a flight of stairs and not feel like you'll fall over.”
A fit person would have a resting heart rate (measured first thing in the morning) around or below 60 beats per minute, she said.
The study examined how changes in cardiorespiratory fitness and BMI, (body mass index, a measure of obesity based on a calculation of height and weight) were connected to cardiovascular disease deaths and death from all causes.
Researchers used treadmill tests and comprehensive medical exams to measure the cardiorespiratory fitness of male participants who averaged 44 years of age.
Researchers recorded changes in BMI and fitness over six years and categorized men into groups that either lost, maintained or gained fitness.
Then, during 11 years of follow-up after the final fitness exam, researchers determined the relative risks of dying among men who were categorized as having lost, maintained or gained fitness during the initial six-year study period.
Accounting for factors that can affect outcomes, such as age, family history of heart disease, behavior such as smoking, and medical conditions such as high blood pressure, researchers determined that BMI change (weight loss) was not significantly associated with risk of death, but losing fitness was linked to a higher death risk.
Men who maintained fitness had 30 percent lower risk of all-cause mortality, and a 28 percent lower risk of cardiovascular disease deaths. Men who improved their fitness had 40 percent lower risk of all-cause deaths and 44 percent lower risk of cardiovascular disease deaths.
Every unit of increased fitness, measured by what's known as a metabolic equivalent, was associated with a 19 percent lower risk of death from heart disease and strokes, and a 15 percent lower risk of death from any cause.
One possible explanation for these results, according to the study, was that about 90 percent of the men were either normal weight or overweight at the beginning of the study. In obese people, BMI changes might have a significant effect on death risk. So it's unclear whether these results would apply to severely obese people, Lee wrote.
And, because the study was mostly done in white, middle- and upper-class men, it's difficult to know whether the results apply to other racial and socioeconomic groups. Women would likely have similar results as the men in the study, according to Lee.
Putting it into practice
Dr. Karen Oppenheimer, in internal medicine at Bend Memorial Clinic, said BMI still plays a factor in a person's health — it's correlated with diabetes, for example. This study is not saying that BMI doesn't matter at all, she said.
Rather: “Weight loss advice comes secondary. Weight loss does (typically) naturally follow from exercise. My priority is to get (patients) out and exercising.”
Dr. Kathi Antolak, a family practice physician at BMC, tells her patients they can be healthy even if they may never be skinny. For example, she knows marathon runners who are not slender, she said. They are certainly fit. But some people feel better being thin, both physiologically and psychologically, she said.
“Sometimes you have to lose weight to feel comfortable going to the gym,” she said.
And sometimes being overweight creates knee and hip pain that prevents people from some weight-bearing exercise. For those people getting started, she recommends swimming and water exercise that are easy on the joints.
Fit people probably exercise 20 to 30 minutes a day, three to four times a week, she said. Some recommendations suggest 60 minutes a day, four to five times a week. New studies suggest that breaking up exercise into smaller segments — two or three 20-minute segments in one day — is better, she said.
Bottom line, experts say, is to find some activity you enjoy and do it as much as you can.
“The best exercise is the one that you do,” Antolak said.