Rodent of the Week: Exercise protects the heart by storing nitric oxide

People who exercise are less likely to have a heart attack, studies show. Moreover, physically active people who do have a heart attack may not sustain as much heart damage compared to sedentary heart-attack patients. Now researchers have a better understanding of why exercise is so protective.

In a recent study, scientists found that the heart is able to produce and store a natural substance called nitric oxide that helps strengthen the heart muscle. Nitric oxide is produced during exercise. It plays several roles in the body, including relaxing blood vessels.

Researchers took mice that had exercised regularly for four weeks on a treadmill and examined them after they sustained a blocked coronary artery -- the type of injury that causes a heart attack. The amount of muscle damaged was less after the exercise period. A week after stopping exercise, the heart muscle still appeared protected by nitric oxide stores. But the effect disappeared after four weeks of no exercise.

“Our study provides new evidence that nitric oxide generated during physical exercise is actually stored in the bloodstream and heart in the form of nitrite and nitrosothiols,” which are more stable types of nitric oxide chemicals, the lead author of the study, David Lefer, a professor of surgery at Emory University School of Medicine, said in a news release.

The study was published online in the journal Circulation Research.

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