According to one study a force of up to three times body weight can be exerted on the human foot while running, and it can be much higher at times. Multiply that by each foot fall in a mile, and you have tons of weight absorbed through the joints and connective tissues. While some people are uniquely suited to do this high impact/high intensity jogging for decades of their adult life, many are not.
For those who want to extend their running life there is a solution; keep running and substitute one running day with one session of high intensity interval training (HIIT) for strength. One less day a week of pounding and you'll have stronger muscles protecting those joints. Add up all those daysover the course of years of giving your joints a break. Your joints will thank you for it.
At Austin Strength Trainers and at New Orleans Strength Trainers our HIIT full-body workout takes about 25 minutes, and it's non-stop. We use MedX equipment. The special medical-rehab features make it easier on the joints. Anybody of any age can do it; each week you do a little bit more that you are used to handling. Muscles are worked to a deep fatigue, and it is cardiovascularly demanding – just like running. It will add years to your running life and to your life in general.