Regular exercise can cut the likelihood of developing the degenerative eye disease, age related macular degeneration by 70%, suggests research published ahead of print in the British Journal of Ophthalmology.
Age related macular degeneration, or ARMD for short, refers to a condition in which the light sensitive cells in the macula at the back of the eye stop working. This affects central vision and therefore activities, such as driving.
It is usually divided into two types--"dry" or non-exudative AMRD--and "wet" or exudative AMRD.
The authors base their findings on the number of cases of AMRD arising over 15 years among almost 4,000 US men and women in Beaver Dam, Wisconsin .
Participants were aged between 43 and 86 at the start of the study in 1988-90, and were assessed at five yearly intervals. As well as detailed eye examinations, they were asked about their lifestyle and the amount of regular physical activity they took, including climbing flights of stairs, daily walks, and sessions of formal exercise.
One in four had an active lifestyle, and nearly one in four climbed more than six flights of stairs a day while around one in eight walked more than 12 blocks a day.
After taking account of other risk factors, such as weight, blood fat levels, and age, those with an an active lifestyle were 70% less likely to develop "wet" AMRD than those who had a sedentary lifestyle.
Regular walkers were 30% less likely to develop this variant.
Other factors, such as diet, may explain the findings, caution the authors. But physical activity is known to reduce systemic inflammation and irregularities in cells lining the arteries, both of which are thought to have a role in the condition, they say.
Physically active people are also likely to be "biologically" younger than those with a sedentary lifestyle, which could also be important as AMRD is associated with ageing, they add.
Journal
British Journal of Ophthalmology