According to a review of evidence in a medical journal, runners live three years (long) than non－runners. You don't have to run fast or for long (see) the benefit. You may drink, smoke, be overweight and still reduce your risk of (die) early by running.
While running regularly can't make you live forever, the review says it (be) more effective at lengthening life walking, cycling or swimming. Two of the authors of the review also made a study published in 2014 showed a mere five to 10 minutes a day of running reduced the risk of heart disease and early deaths from all (cause).
The best exercise is one that you enjoy and will do. But otherwise... it's probably running. To avoid knee pain, you can run on soft surfaces, do exercises to (strength) your leg muscles (肌肉), avoid hills and get good running shoes. Running is cheap，easy and it's always (energy). If you are time poor, you need run for only half the time to get the same benefits as other sports, so perhaps we should all give a try.
