Older runners were found to have an active life longer and are half as likely to die early than other people, a new study said.

Researchers studied 500 older runners for more than 20 years and found that they had fewer disabilities and were active later in life.

Dr. James Fries said his research started to disprove theories that older runners would suffer more injuries that would limit the benefits of exercise. He thought that staying active would compress the period at the end of life when people couldn't carry out daily tasks.

His team started annual tracking of 538 runners older than 50 and a similar group of nonrunners in 1984.

After 19 years, 34 percent of the nonrunners had died, compared to only 15 percent of the runners, even though the time spent running each week has declined as people reached their 70s and 80s.

Running slowed cardiovascular deaths and was also associated with fewer early deaths from cancer, neurological disease, infections and other causes.

Surveys also found that the first signs of disability came 16 years later than for the runners.

Fries' previous work showed that the runners did not have higher rates of arthritis, either.

The new findings will appear in the Aug. 11 issue of the journal Archives of Internal Medicine.