How Cycling, Running and Walking Can Help Save Your Sight

How Cycling, Running and Walking Can Help Save Your Sight

Every hour of riding per day could reduce your risk of Cataracts by two percent, a new study shows. Read on…

By Selene Yeager

  • Regular exercise reduces your risk of developing age-related cataracts, which is the leading cause of blindness in the U.S., according to a study published in the International Journal of Ophthalmology.
  • Exercise appears to protect the lens of the eye by ramping up the body’s natural antioxidant defense against free radical damage.
  • Every hour of physical activity a day may reduce cataract risk by two percent.

The more active you are, the less likely you are to develop age-related cataracts, according to a scientific research review including more than 170,000 people world wide.

Cataracts are a clouding of the eye lens that typically occurs with aging. Ninety-five percent of cataracts are age-related and generally develop after age 40. They are the leading cause of blindness among older adults in the U.S.

Though the exact mechanisms that cause age-related cataracts are unknown, free radical cell damage, insulin resistance, and unhealthy lipid (aka cholesterol and triglyceride) profiles raise the risk.

In a recent paper published in the International Journal of Ophthalmology, researchers from Xi’an Jiaotong University and the University of South Australia (UniSA) analyzed data from six different studies looking at how exercise reduces oxidative damage in the eye.

The researchers found that people who performed regular exercise like cycling, running, and walking were 10 percent less likely to develop age-related cataracts. For one, physical activity reduces oxidative stress—the imbalance between the natural production of cell-marauding free radicals and the body’s antioxidant defense system.

In the eye specifically, reducing oxidative stress protects the lens’ high concentration of polyunsaturated fatty acid from breaking down; that breakdown results in cell damage, study researcher and UniSA epidemiologist Ming Li, Ph.D., said in a press release.

“We know that exercise increases antioxidant enzyme activity which has all sorts of benefits, including limiting infections and inflammation in the eye,” Li said in the release.

The study suggested that the risk for age-related cataracts decreased by two percent for every six METs per day increase in physical activity. For reference, one “metabolic equivalent” (MET) is the amount of oxygen you use just sitting watching YouTube videos; any amount of exercise you do over that increases your MET demand. An activity that requires six times that amount of oxygen—six METs—would be the equivalent of an hour of leisurely pedaling, or 30 minutes of riding at 18 or 19 mph without drafting.

Previous studies have shown that long-term physical activity also raises HDL (high-density lipoprotein), otherwise known as the ‘good cholesterol,’ which may help ferry more antioxidants from the blood plasma to the eye’s lens to prevent oxidative damage.

Exercise also improves insulin resistance and lipid profiles, both of which may pave the way for the development of age-related cataracts.

Speaking of eye protection—cycling is often done outdoors, and chronic sunlight exposure can increase the risk of cataract. So remember to always protect your eyes with 100% UVA- and UVB-protection sunglasses while you’re out there getting your daily dose of exercise.

By Selene Yeager in How Cycling Can Help Save Your Sight >

Background Photo by Paul Green on Unsplash

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