What It Is
Running is probably the oldest form of cardio; our species has been doing it since we stopped scrambling around on all fours. Even though we no longer need to flee woolly mammoths, running still has lots to recommend it: It's convenient (no class schedule to follow), takes minimal coordination (unlike the latest crumpin' class), and requires little equipment beyond a decent pair of shoes.
Running is also a high-impact workout that strengthens bones and muscles (the most important being your heart), increases energy, and burns an average of 600 to 860 calories an hour, depending on your size and pace. Devotees find it meditative and stress relieving, like yoga. Studies show it can be as powerful a mood-elevator as medication, and that runners live longer than nonrunners.
The People It's Good For
Just about anyone with two good legs, even if the only running they've done is for the bus.
Note: If you're pregnant or significantly overweight, you should check with your doctor first.
The People It's Not Good for
Those with an injury or with foot, knee, hip, or lower-back problems, since running can exacerbate all of these. Don't lace up your shoes until you're fully healed.
What You Need to Know
When you set out to run, remember these three words: Take it slow. The idea of trying something new -- or getting back into it -- may give you marathon-size motivation. But to enjoy running and come away injury-free, you should lower your expectations by about 24.2 miles. "Beginners tend to go too fast or too far," says Gordon Bakoulis, a running coach in New York City. "They end up burning out quickly, getting discouraged, and often getting injured."
What to Do Before
Do a five-minute warm-up to ease your muscles into your run. Try jumping jacks, jogging in place, or even a slow starting pace. Also, drink one glass of water an hour or so before you exercise. If you like to stretch, go ahead, but recent research shows that limbering up doesn't help prevent injuries or muscle soreness. "A lot of runners like to stretch their quads, calves, and hamstrings because it feels good and makes them less stiff when they're starting out," Bakoulis says. "But it's skippable."
Where to Run
A flat, packed-dirt trail or a track is best for beginners because the surface is more forgiving than asphalt. Experts tell novice runners to avoid running on trails with lots of uneven terrain; the lateral movement is too hard on ankles and knees. And when you have a choice between the treadmill and sidewalks, pick the pavement. "It's a better workout than running on a treadmill with no incline," says Lynn Millar, a professor of physical therapy at Andrews University in Berrien Springs, Michigan. "Treadmills actually help propel you forward, so your butt and hamstrings don't have to work as hard." (If you do prefer a treadmill, always set the incline to at least level 1.) Now for a quick safety PSA: If you're going to run outdoors, especially at night, be sure to pick a well-lit road (or track) and jog against traffic, so you can always see oncoming cars. Refrain from listening to music at night, and don't crank up the tunes during the day. The volume should be low enough to allow you to hear your surroundings, including footsteps and car horns. The ideal scenario is to run with a friend or to join a club (log on to nyrr.org to find a partner or runners' group in your area).