And don't even think about running in your regular cross-trainers, tennis shoes, or regular sneakers.
"Running is very traumatic," says Forrest Dolgener, exercise physiologist and professor of exercise science at the University of Northern Iowa in Cedar Falls. "The mechanics of running creates specific kinds of forces on the body. Running shoes are designed to absorb and minimize those kinds of forces."
But don't get too attached to your favorite pair. Running shoes have a limited lifespan, says Dolgener, co-author of The Non-Runner's Marathon Trainer.
"Generally speaking, running shoes have 500 miles of life," he says. "Even though they make look good, shock absorption diminishes after 500 miles."
Before you start any new fitness program, it's wise to consult with your physician -- especially if you're a man 45 or older or a woman 50 or older, the experts say.
"I always want anyone who's getting started to know their life digits -- blood pressure, BMI (body mass index), cholesterol, blood sugar," says Isphording.
Running is not the best exercise for everyone, Dolgener says. So listen to your doctor and your body.
"The worst thing you can do is start running, get injured, then stop exercising altogether," says Dolgener.
Once you get a green flag from the doctor, don those new running shoes and start out with a combination of walking and jogging. For example, you might alternate walking for five minutes and jogging for two minutes.
Over time, steadily increase the amount of time you spend running until you're able to jog for 20 minutes at a time, suggests Isphording. Once you achieve that, start increasing your distance.
For someone who has been sedentary, Dolgener recommends starting only with walking, then progressing to brisk walking before adding any jogging.
"Progression is the key element for someone who hasn't done this," says Dolgener.
Your cardiovascular system will adapt more easily than your musculoskeletal system, says Dolgener. People don't usually give up running because their hearts can't adapt but because of injury. Gradually conditioning yourself with a combination of walking and running gives your body time to adapt to the new stress on the joints and muscles.