Long-term exposure to air pollution is already known to increase the risk of heart trouble. According to World Health Organisation estimates, nearly 800,000 premature deaths worldwide can be attributed to pollution each year.
20 male volunteers, all survivors of heart attacks were studied by Nicholas Mills and colleagues at Britain??s Edinburgh University. The volunteers were all made to pedal an exercise bike. An idling Volvo diesel engine emitting diluted fumes was placed nearby so that the volunteers were directly inhaling those fumes.
The diesel exhaust provided researchers with a pollution exposure level comparable to that faced while driving in traffic. The researchers were attempting to study a particular suspect element of air pollution and its affect on people over the short term.
The research team found that when the volunteers inhaled the diesel fumes, their hearts got starved of oxygen. The likelihood of this happening was far greater in the presence of the fumes than when they were breathing clean air.
A blood test of the men revealed that the diesel fumes interfered with the body??s natural system of breaking down clots and stopped it from doing so. This can lead to a heart attack or stroke. The researchers believe this might be the reason behind population-based studies finding air pollution to increase heart problems.
They were however unable to find the exact reason behind the hearts of the volunteers becoming starved of oxygen; they were also unable to determine which element in the fumes was responsible for causing such an effect.
??The study was specific in evaluating the effects of dilute diesel exhaust, an extremely complex mixture of particles and gases; it is not possible to glean which constituents of diesel exhaust were responsible for the observed effects,? Dr. Murray Mittleman, of Boston??s Beth Israel Deaconess Medical Center said.
??Although the study was only done on men with a previous heart attack, these findings may represent the tip of an iceberg and apply to anyone at risk for a heart attack,? he said. ??Exercise is already known to be beneficial and it especially decreases the risk that a man will have a heart attack while exerting himself,? said Dr. Mittleman and added, ??The risk-benefit ratio may be optimised if people exercise away from traffic when possible.?