Age-related cataracts (ARC) are the leading cause of blindness in an estimated 13 million people worldwide, but new research finds that physical exercise may help to reduce the risk of eye disease. Chinese and Australian researchers combined studies of more than 170,000 people to find the relationship between physical activity and cataracts.
Published in the International Journal of Ophthalmology, researchers from the University of South Australia (UniSA) and Xi’an Jiaotong University used data from six studies to examine how exercise reduces oxidative damage in the eye.
It was found that in people who engaged in regular physical activity such as walking and cycling, there was a 10 percent reduction in age-related cataracts. Researchers believe that exercising can reduce oxidative stress in the eye by inhibiting lipid degradation which results in cell damage.
UniSA epidemiologist Dr. Ming Li said, “We know that exercise increases antioxidant enzyme activity which has all sorts of benefits, including limiting infections and inflammation in the eye.”
Previous studies also may point to a reason why physical exercise can impact eye health. It has been shown that long-term physical activity elevates HDL (high-density lipoprotein), or ‘good cholesterol.’ This type of cholesterol has been found to carry more antioxidants from plasma to the lens to prevent oxidative damage. Exercise also advances insulin resistance and lipid profiles, both of which have been associated with an increased risk of ARC.
“Age-related cataracts are one of the most common causes of vision impairment and blindness in the world and although surgery is an effective option to recover vision, it is very costly,” Dr. Li says.
“The lens is highly susceptible to oxidative damage because of its high concentration of polyunsaturated fatty acid and its specific biological function. Although we don’t completely understand the mechanisms underlying ARC, we do know that aging and oxidative damage play a crucial role in the development of the disease.”
For every hour of cycling or walking per day, researchers believe that the risk of developing cataracts could decrease by two percent. This is just another example of the benefits of daily physical exercise. To help reduce the risk of cataracts and many other health issues, the Department of Health and Human Services recommends getting at least 150 minutes of moderate aerobic activity or 75 minutes of vigorous aerobic activity a week. This not only includes walking, cycling, and swimming, but there are many other ways to get the heart pumping including taking a group class at a gym or going for a hike.
“Considering the fact that 24 percent of adults are inactive, these findings will hopefully encourage older people to start exercising on a regular basis,” Dr. Li says.