Can exercise weaken the link between obesity and heart damage?
Even though heavy adults can be more prone to cardiac problems than their slimmer peers, exercise may lower the odds of heart damage for obese people, a recent study suggests.
Researchers examined data on 9,427 middle-aged people without cardiovascular disease to see how their weight and exercise habits might influence levels of a protein that’s a marker of heart damage.
Overall, 7.2 percent of the participants had elevated levels of a protein known as high-sensitivity cardiac troponin T (hs-cTnT). Rising levels of this protein can be an early warning of future heart failure in people who don’t have symptoms.
Compared to non-obese people who got at least 75 minutes of vigorous exercise or 150 minutes of moderate intensity activity each week, sedentary obese people were about 2.5 times more likely to have high levels of this protein, the study found.
But obese people who met the same recommended exercise targets as their non-obese counterparts were only 68 percent more likely to have elevated cardiac troponin T levels.
“This suggests that physical activity prevents at least some of the heart damage associated with obesity,” said lead study author Dr. Roberta Florido, a cardiovascular health researcher at Johns Hopkins University in Baltimore.
“Although the mechanisms underlying this protection are incompletely understood, it is possible that at least part of it involves improvements in blood pressure, cholesterol and other metabolic abnormalities that occur with obesity,” Florido said by email.
At the start of the study, participants were typically around 60 years old and they tended to be overweight, if not obese.
Researchers counted people as meeting “recommended” exercise levels based on minimum weekly activity targets set by the American Heart Association: either 150 minutes of moderate or more vigorous activity or at least 75 minutes of intense activity.
Overall, 43 percent of participants hit this target and another 23 percent got some activity but fell short of the minimum recommended amount. Another 34 percent of participants didn’t get any activity of at least moderate intensity in a typical week.
Researchers followed at least half of the participants for 15 years. During the study period, 1,178 people developed heart failure.
Non-obese people who met recommended activity goals had the lowest rates of heart failure, while sedentary obese people had the highest rates.
One limitation of the study is its reliance on questionnaires to measure activity levels, which might not fully capture the effect of exercise on the odds of heart damage, the authors note in the Journal of the American college of Cardiology: Heart Failure.
Researchers also lacked data on when heart damage developed in those who had it.
Even so, the findings add to growing evidence linking more exercise to lower odds of heart disease, said Dr. Tariq Ahmad, a cardiovascular medicine researcher at Yale University School of Medicine in New Haven, Connecticut.
The challenge is getting patients to exercise, Ahmad, author of an accompanying editorial, said by email.
“It is very easy to prescribe medications but difficult to get patients to exercise,” Ahmad said. “If you can tell patients that activity can reduce their risk of heart damage, perhaps it will be more meaningful.” — Agencies