MONDAY, Dec. 13, 2004 (HealthDayNews) -- A person's race may affect his or her -- but especially his -- obesity and fitness levels, claims a new study in the December issue of Chest.
After evaluating 5,069 people referred for an exercise stress test to detect coronary artery disease, Dr. Carl J. Lavie, director of the exercise laboratories at the Ochsner Clinic Foundation in New Orleans, and his colleagues found black patients overall had a higher level of obesity and a lower exercise capacity than white patients. The most pronounced differences, Lavie said, were seen in men.
Lavie said some doctors and consumers perceive blacks as more fit than other races, possibly because of some black athletes' high profiles in professional sports. His study, however, refutes that perception.
The participants included 4,428 whites and 641 blacks, aged 52 to 74. They were evaluated for exercise capacity in simple terms, Lavie said, such as how long they could walk on an incline on a treadmill. Black men, on average, were three years younger than their white counterparts, had a higher body mass index (BMI), and had an exercise capacity that was 7 percent lower, Lavie said.
Black women had a slightly lower exercise capacity than did white women, but the differences weren't statistically significant.
Black men had higher BMIs -- 29.1 compared to 28.2 -- than did white males. A level below 25 is considered healthy. Forty-four percent of the black men were obese, compared to 33 percent of the whites; 37 percent of the black women were obese, vs. 27 percent of the white women.
"I don't think it is a surprise that African-Americans had a high level of obesity," Lavie said. "Other studies indicate that as well."
Lavie said he was not aware of any studies assessing exercise capacity in adult black patients or the impact of one's race on fitness levels.
Exercise capacity is an important measure, Lavie said. Low levels of cardiorespiratory fitness are as strong a predictor of death from heart disease as are more well-known risk factors such as smoking and high blood pressure.
Lavie said part of the reason blacks have lower exercise capacity is related to the higher overall levels of obesity. "But it can't just be explained by that," he said. "We found race independently associated with exercise capacity."
"It wasn't like a night-and-day difference in exercise capacity," he said. But the difference between black men and white men was statistically significant.
Lavie said that everyone needs to pay attention to weight control and physical fitness, but that perhaps doctors should be especially strong in sending the message to black patients.
The study findings come as no surprise to two other experts.
"It's well known that the leanest population is Asian, the second is Caucasian, and then we have a toss-up between Hispanics and blacks," said Dr. Richard Johnson, a clinical professor of family medicine at the David Geffen School of Medicine at the University of California at Los Angeles.
In some cases, Johnson added, financial considerations play a role. "You aren't going to be going to the gym if you can get in overtime and your kids need shoes," he said.
In such cases, he added, the doctor should try to tailor suggestions for physical activity to the patient's lifestyle. "The physician's job is to reduce barriers," he said. "If a patient can't go the gym, suggest he take the stairs, park far away from the store."
If he's time-pressed, he could do a half-hour of exercise in short bursts rather than at one time, he added.
"The study provides important data supporting the concept that obesity is a major contributor for cardiovascular disease as well as other medical conditions," said Dr. Mark Rosen, chief of pulmonary and critical care medicine at Beth Israel Medical Center.
"Because obesity is more common in African-Americans, this message may be particularly important for them," Rosen said.
Whatever a person's race, the advice should be the same, Rosen added. "Everybody should avoid obesity and modify lifestyle," he said, adding those changes include eating a healthy diet and getting regular exercise.
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