Doctors have long known that obesity raises the risk for heart disease later in life, but new research reveals it can damage even young hearts.
British scientists found that young adults who had a higher body mass index (BMI), an estimate of body fat based on height and weight, had higher blood pressure and thickened heart muscle.
"Our results simply suggest that any reduction of body mass index to a normal, healthy level from a young age is likely to prevent the development of adverse cardiovascular health in later life," said study author Kaitlin Wade, a research associate at the University of Bristol Medical School.
"If the obesity epidemic increases, or indeed maintains its current trajectory, it is likely that the future risk of cardiovascular events such as stroke and coronary heart disease will increase," she added.
For the study, Wade and her colleagues used a new genetic analysis to determine if an unhealthy BMI causes spikes in blood pressure or structural changes in the heart. Their analysis included several thousand healthy 17- and 21-year-olds who are participating in an ongoing study.
The researchers found that higher BMI caused higher blood pressure, or more force against the artery walls during and between heartbeats. Being overweight also caused the left ventricle, which is the heart's main pumping chamber, to become enlarged.
Excess weight can make the heart work harder, increasing the amount of blood it has to pump and the pressure it needs to pump against, the researchers explained.
These changes can trigger an increase in heart muscle mass, explained Dr Gregg Fonarow, director of the Ahmanson-UCLA Cardiomyopathy Center in Los Angeles.
Usually, the thickening of blood vessel walls is the first sign of atherosclerosis, a disease commonly known as "hardening of the arteries" that causes fatty plaques to build up within the arteries and block blood flow.
But the new study shows that young people who are overweight may develop even earlier warning signs of heart trouble. The study's findings were published in the journal Circulation.
"Our findings suggest that higher BMIs cause changes in the heart structure of the young that may precede changes in blood vessels," Wade explained.
Obese young people are at higher risk for heart failure and diabetes, and they're also more likely to have a heart attack or stroke at an earlier age, said Fonarow, who is also co-director of UCLA's Preventative Cardiology Program.
"If current trends in obesity continue without effective interventions, prior gains in reducing cardiovascular events and extending life may be lost," he said.
But losing weight can help protect the heart, even later in life. Shedding extra pounds could slow or even reverse these worrisome heart-related changes among young people, Wade said.
Fonarow added that regular physical activity, maintaining healthy blood pressure and cholesterol levels and not smoking can also help improve heart health.
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