Moderate exercise helps prevent the leading cause of vision loss in older adults

Last month, I discussed how experiencing vision problems as you get older isn’t “normal” or unavoidable. In fact, even serious vision problems can be treated (if you catch them early)—or even prevented altogether with key supplements.

And now, a new lab study has found that something you probably already do could help prevent the leading cause of vision loss among older men and women.

I’ll tell you more about that study in just a moment. But first, let’s go over a few things about this devastating eye disease that affects 10 million Americans…

Science slow to tackle eye disease

Age-related macular degeneration (AMD) is the leading cause of vision loss among men and women ages 60 and over. It chiefly affects the macula—at the center of your retina—which contains highly specialized cells needed for sharp vision.

There are two main types of AMD…

The first and most common type, called the “dry” form, results from drusen deposits. (The word drusen comes from the German word for dregs, as in dregs of wine.) These deposits block the retina and cause blind spots.

The second type of macular degeneration, the “wet” form, results from an abnormal proliferation of blood vessels in your eye. (Excess growth of blood vessels also contributes to other eye diseases, such as diabetic retinopathy and glaucoma.) With this form of the disease, blood vessels leak blood and fluids that block the retina. And eventually, scarring leads to serious vision loss.

Only about 10 percent of men and women with AMD develop the “wet” form. But this percentage suffers the most severe visual loss. And it’s what the authors of the new study examined…

Moderate exercise thwarts abnormal blood vessel growth

Previous studies have looked at the effect of exercise on AMD risk in older adults. But those studies relied on participants to report back about their exercise levels. And, as I’ve said before, self-reported data is particularly unreliable.

So, for this new study, researchers with the University of Virginia School of Medicine took a different approach…

They used lab mice.

First, they divided the mice into two groups: One group was placed in cages with an exercise wheel. The second group was placed in cages without a wheel.

After four weeks, the researchers removed the mice and gave them surgery to induce the abnormal overgrowth of blood vessels in the eye, as seen in “wet” AMD. Then, they put the mice back in their respective cages.

As you might expect, the mice with the wheel performed some “voluntarily” exercise weekly. And it turns out, they had 45 percent less excess blood vessel growth compared to their sedentary peers.

When the researchers repeated the experiment, the results were slightly more modest—but the active mice still had an impressive 32 percent less excess blood vessel growth.

The researchers admitted they don’t quite understand how moderate exercise prevents this kind of blood vessel growth. But they theorized that increasing blood flow and circulation could prevent the biochemical signals that tell the body it needs to grow more blood vessels.

In addition, as I discussed yesterday, even passive stretching of the legs improves the health of blood vessels in the legs and upper arms. So, clearly, light movement has a general, systemic benefit.

In any case, the researchers said they want to learn more about this process so they can “develop a pill” to gain all the benefits of exercise…without having to exercise. (Like the elusive diet pill that can cause you to lose weight, without actually following a healthy diet and exercise lifestyle!) That’s because they cited concerns that older people, “may not be capable of conducting the type of exercise regimen that may be required to see some kind of benefit.”

But wait—didn’t this very study just show that a little bit of exercise goes a long way? And that protecting your eyes DOESN’T require a strenuous exercise regimen?

So, in my view, we need to simply trust these results, skip the drugs, and just keep up with light exercise—like walking, gardening, and housework.

Now, let’s go over one last takeaway from this study…

More isn’t better when it comes to exercise

Like humans, the mice in this study exercised for a range of different times each day. They were active for as long as they felt like being active. And just doing that much was enough to confer significant benefits for the eyes. In fact, the researchers noted that the minimum requirement for getting the benefits from exercise was quite low.

Of course, mice can be induced to perform more exercise. And humans certainly can (and do) force themselves to perform excess exercise, too (or what I call “excess-ercise”)—like run marathons.

But this study, like so many before it, found that there was no additional benefit beyond what the mice performed naturally. In other words, more wasn’t better. In fact, on the contrary, as I reported last summer, excessive exercise can actually cause serious harm, especially to your eyes.

In the end, it once again appears that your body knows what it needs. And doing whatever amount of activity “feels right” is also the right amount for health.

So, this week, try to listen to your body when you exercise. (And not to the exhortations of trainers, coaches, the fitness industry, or even your peers.)

In fact, I encourage you to get some light-to-moderate exercise in Nature, where you will feel less of a need to compete and overdo things. Plus, simply spending time in Nature, doing absolutely nothing, confers significant health benefits!

You can learn more about how to protect your vision at any age in the August issue of my monthly newsletter, Insiders’ Cures (“My ABCs for brain and eye health”). If you’re not yet a subscriber, now is the perfect time to get started.


“Voluntary Exercise Suppresses Choroidal Neovascularization in Mice.” IOVS, 2020 DOI: 10.1167/iovs.61.5.52