Jogging, once thought to be too strenuous for middle aged people is considered to be not only healthy but beneficial enough to add years to your life.

Researcher Peter Schnohr told delegates that the study’s most recent analysis, which has yet to be published, shows that between one and two-and-a-half hours of jogging per week at a “slow or average” pace delivers optimum benefits for longevity.

“The results of our research allow us to definitively answer the question of whether jogging is good for your health,” said Schnohr, who is chief cardiologist of the Copenhagen City Heart Study. “We can say with certainty that regular jogging increases longevity. The good news is that you don’t actually need to do that much to reap the benefits.”

Always consult your physician when beginning a new exercise.

The hips and knees receive continuous stress from walking, running, sporting activities, or injury and are more commonly affected by the wearing of cartilage (degenerative arthritis) than the hand joints.

However, the joints of the hand do experience stress in everyday use, and because the hand joints are smaller, these stresses are concentrated over a smaller surface area.

The high ratio of stress to surface area can cause the smooth joint cartilage to wear over the years.

As the cartilage degenerates, the underlying bone becomes exposed.

When the deteriorated joint moves, bone rubs upon bone causing pain, swelling, limiting motion, and frequently causing a grinding or popping sensation.

Since performing one of the nation’s first total hip replacements 42 years ago, Rothman has replaced more than 25,000 hips and knees. The physically taxing procedure, which swaps the boney joint for a prosthetic usually made of titanium and hard plastic, revolutionized the treatment of arthritis.

“Prior to that, if you have a bad hip or bad knee there were no good options,” he said. “You got crutches or a wheelchair.”

Joint replacement surgery is on the rise and is expected to keep rising as the population ages. Between 1996 and 2006, the number of total hip and knee replacements increased by 30 percent and 70 percent respectively, according to a CDC report.