Los Angeles - Life is full of worries. When you're battling a chronic illness, it seems almost impossible to escape nagging anxieties. When will I feel better? Will my condition worsen? When can I return to work or school?

But if you exercise regularly, you probably will feel much less anxious - regardless of the status of your illness. In a study published yesterday in the Archives of Internal Medicine, researchers analyzed data from 40 studies on how exercise affects anxiety. All of the 3,000 study participants were sedentary individuals who had chronic illnesses but were able to exercise in sessions of at least 30 minutes.

Compared with similar individuals who did not exercise, those who exercised had a 20 percent drop in anxiety symptoms. Exercise helped with almost all kinds of health problems: cancer, depression, heart disease, fibromyalgia. Multiple sclerosis was the only condition in which exercise did not appear to have a significant effect.

"We found that exercise seems to work with just about everybody under most situations," said Pat O'Connor, co-author of the paper and a professor at the University of Georgia in Athens, in a news release. "Exercise even helps people who are not very anxious to begin with become more calm."

Exercise is known to lessen the symptoms of depression, but less attention has been paid to its effects on anxiety.