New studies find exercise makes for better eye health, less chronic pain, stronger bones and can even help prevent some cancer. Image

It just seems too good to be true. Study after research study consistently promoting the endless benefits of exercise. Couch potatoes everywhere are waiting for the other shoe to drop, telling us that all of those scientists were wrong and we should remain as sedentary as possible.

Yet four additional studies released recently each give the same prescription for improving some aspect of your health: exercise.

They add to recent evidence that regular workouts can improve old brains, raise kids' academic performance and give a brain boost to everyone in between.

Better bones One study illustrates the effect of exercise on preventing or limiting osteoporosis, which affects more than 200 million people worldwide. Researchers at the University of Missouri found that while both resistance training (lifting weights) and high impact exercise (running) both help build needed bone mineral density (BMD), running is the better choice.

"Exercise programs to increase bone strength should be designed using what is known about how bones respond to exercise," said Pam Hinton, associate professor and lead author. "Only the skeletal sites that experience increased stress from exercise will become stronger. High-impact, dynamic, multi-directional activities result in greater gains in bone strength."

The study was published in the February issue of the Journal of Strength Conditioning.

Less pain In a related study, exercise seemed to be one of the few successful remedies for those that suffer from low-back pain. In the February issue of the Spine Journal, University of Washington physicians summarized 20 different clinical trials that promoted different solutions to alleviating pain.

"Strong and consistent evidence finds many popular prevention methods to fail while exercise has a significant impact, both in terms of preventing symptoms and reducing back pain-related work loss," said Dr. Stanley J. Bigos, professor emeritus of orthopaedic surgery and environmental health. "Passive interventions such as lumbar belts and shoe inserts do not appear to work."

Better eye health Also, vigorous exercise has now been linked with significantly reduced onset of cataracts and age-related macular degeneration. In the study, detailed in Investigative Ophthalmology and Visual Science, researchers reviewed the eye health of 41,000 runners over seven years and found that both men and women had significantly lower rates of these two diseases than the general public.

Men who logged more than 5.7 miles per day had a 35 percent lower risk than those that ran less than 1.4 miles per day. While the correlation is strong, the reason is not clear.

"We know some of the physiological benefits of exercise, and we know about the physiological background of these diseases, so we need to better understand where there's an overlap," said Paul Williams, an epidemiologist in the Lawrence Berkeley National Laboratory Life Sciences Division.

Cancer prevention Each year in the U.S., more 100,000 people are diagnosed with colon cancer. To see what effect exercise has on lowering this rate, researchers at Washington University and Harvard University combined to review 52 studies over the last 25 years which linked exercise and the incidence of cancer. Overall, they found that those that exercised the most (5-6 hours of brisk walking per week) were 24 percent less likely to develop the disease than those that exercised the least (less than 30 minutes per week).

"The beneficial effect of exercise holds across all sorts of activities," said lead study author Kathleen Y. Wolin, Sc.D. of Washington University. "And it holds for both men and women. There is an ever-growing body of evidence that the behavior choices we make affect our cancer risk. Physical activity is at the top of the list of ways that you can reduce your risk of colon cancer." So, are there any studies out there that link exercise with a negative outcome?

In a recent study published in the journal Obesity, Dolores Albarracín, professor of psychology at the University of Illinois, did find that people who are shown posters with messages like "join a gym" or "take a walk" actually ate more after viewing these messages than those that saw messages like "make friends."

"Viewers of the exercise messages ate significantly more (than their peers, who viewed other types of messages)," Albarracín said. "They ate one-third more when exposed to the exercise ads."

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Dan Peterson writes about sports science at his site Sports Are 80 Percent Mental.