Running too much?

Running may be good for your health, but too much running may be harmful.

Some new research suggests that runners appear to live longer.

However, another new study looks at the link between running and cardiovascular-related deaths.

The scientists found that running lowered the risk for death when a person did not exceed more than 20 miles a week, log more than five to seven miles per hour, or run more than two to five times a week,

Another study found that extreme endurance training -- such as that performed by marathoners, triathletes, professional cyclists and ultra-marathon runners -- can lead to long-term heart damage. #