People who exercise in areas where there is heavy traffic may be especially at risk, researchers say.
They tested the heart health of 20 recruits, who had stable coronary heart disease, in normal air and then in air polluted by diesel fumes while they pedalled on an exercise bike.
Within six hours the heart health of the participants had deteriorated dramatically after they had exercised in the polluted air. Even a short burst of exercise in air filled with diesel fumes could dramatically increase the risk of a heart attack, especially if you have an existing heart condition, the researchers said.
(Source: New England Journal of Medicine, 2007; 357: 1075-82).