People with advanced heart disease have arteries that are biologically 40 years older than their real age, a study by the British Heart Foundation suggests.
Patients who had undergone heart surgery were examined
Researchers from Cambridge University examined tissue from patients who had undergone heart surgery to study how artery cells age.
Published in Circulation Research, it warned the ageing process could not be reversed in severely damaged cells.
The findings are hoped to make a step towards preventing heart attacks.
The experts identified telomere damage - a biological sign of DNA ageing in the smooth muscle cells of diseased blood vessels.
In patients with heart disease, the artery cells divided up to 13 times more rapidly than normal, prematurely ageing them.
When artery cells age, they are less able to prevent fatty deposits from forming. This can narrow the arteries and cause heart attacks.
Professor Martin Bennett, British Heart Foundation (BHF) professor of cardiovascular sciences and one of the researchers, said in the early stages of heart disease the arteries are between five and 15 years older than the person's real age.
"If you have mild heart disease and can limit your risk factors by stopping smoking, controlling hypertension and diabetes, and taking statins to lower cholesterol, you will slow this ageing process," he said.
"If you do nothing, the cells can reach extreme old age very prematurely - and once they do that, the process cannot be reversed," he warned.
Professor Peter Weissberg, medical director of the BHF, said ageing cells' inability to repair themselves efficiently was one of their "defining features".
"The older the tissue, the less able it is to deal with physical or biochemical injury," he said.
"This research suggests that if blood vessel cells could be prevented from ageing so quickly, then potentially heart attacks could be prevented.
"This opens up a new avenue of research aimed at preventing heart attacks."