Exercising on polluted city streets does more harm than good, research suggests
Exercising on polluted city streets does more harm than good, research suggests.
The damage done by breathing in traffic fumes outweighs the benefits of physical activity, scientists found.
Inhaling polluted air even for two hours was seen to stiffen arteries and reduce lung function, countering all the good done by a workout.
But the researchers, from Imperial College London and Duke University in the US, also discovered that air pollution is very localised – so leaving a busy street and exercising in a park instead was enough to reverse the trend.
The study, in the Lancet medical journal, warned breathing in pollution from diesel cars is particularly dangerous.
The scientists tested 119 over-60s as they walked for two hours in central London. Half walked on Oxford Street and the other half through a quiet section of nearby Hyde Park.
The study found everyone in the park group benefited, with lung capacity improving within an hour and persisting for 24 hours.
Blood flow increased, blood pressure fell and arteries became 24 per cent less stiff.
But for those in the Oxford Street group there was only a tiny increase in lung capacity, and arterial stiffness got 7 per cent worse.
Researchers said this was linked to the black carbon soot and ultrafine particles from diesel fumes, which have been linked to higher risk of cardiovascular disease, asthma and death.
The damage done by breathing in traffic fumes outweighs the benefits of physical activity, scientists found
Professor Fan Chung of Imperial, senior author, said: ‘It shows we can’t really tolerate the levels of air pollution we currently find on our busy streets.
‘For people living in the inner city it may be difficult to find areas where they can walk, away from pollution … we really need to reduce pollution by controlling traffic.’
The researchers believe the findings would apply to other age groups.
They also found volunteers taking heart drugs such as statins were less affected by the air pollution, suggesting the drugs might protect against the damage.
Simon Gillespie, of the British Heart Foundation which funded the study, said: ‘Telling joggers to avoid polluted streets is not a solution … The Government must put forward bold measures to make all areas safer for our hearts and clean up the UK’s toxic air.’