How will I benefit from bicycling?For starters, you'll tone your calves, thighs, and hips while burning 350 to 700 calories an hour. Cycling boosts your aerobic capacity, too -- new cyclists see up to a 20 percent increase during the first four months. That means your heart will deliver oxygen to muscles more efficiently, taking the effort out of climbing stairs and carrying groceries. You'll also reduce your risk of colon cancer and lower your cholesterol level and blood pressure. And bicycling is one of the few aerobic exercises that's easy to incorporate into a full day. On a bike, you can run errands or commute to work.

How should I choose a bicycle?Your best bet is a city bike or hybrid, and don't let bike shop employees tell you differently. Halfway between a mountain bike and a road bike, a city bike is designed for use around town. As their names imply, the other bikes are intended for dirt tracks in mountains or the open road. They fall woefully short when asked to perform everyday duty.

Make sure you get a comfy seat, and look for handlebars that allow you to maintain an upright position (you should lean forward slightly, but not so much that you can't let go of the bars without falling forward). Having fenders, a rack, and a basket will encourage you to use the bike for chores as well as exercise.

You can get a rough idea of whether a bike fits by straddling the frame and making sure your crotch clears the top bar by a couple of inches. Adjust the seat height so that your knee bends slightly when the pedal is at the lowest point. If your hips rock from side to side when you pedal, it's too high. The salesperson should be very helpful in guiding you to the right bike and setting it up to suit you; if not, go someplace else.

Toe clips, metal cages that help keep your feet in contact with the pedal, can save your knees by allowing you to lift up as well as push down when you're turning the cranks. It'll take a couple of outings to get used to the clips, but after that you won't feel comfortable riding without them. Eventually, if you want to extend your pastime into doing long weekend rides, you may want to get clipless pedals, which call for cycling shoes that snap into place.

Whatever you do, don't leave the store without buying a helmet: Wearing one reduces the risk of serious head injury by more than 85 percent.

What's a good cycling technique? Fluidity is key in cycling. Keep your upper body still and concentrate on your pedal stroke as a full circle; don't just stomp down as each foot comes forward. Stay in a gear that allows you to spin the pedals at about 70 to 80 revolutions a minute. To get a feel for this, try counting "one potato, two potato, three potato"; your right foot should reach the bottom of the stroke as you say the number. It may seem too fast at first, but you'll quickly adjust. This cadence will get you through valleys and over hills efficiently, and it will help prevent stressed joints and strained muscles.

If you remember to shift down anytime your cadence slows, you'll do fine. "Cycling is a sport of elegance, subtlety, and finesse," says cycling pro James McCullagh in his book Cycling for Health, Fitness and Well-Being. "Only the foolhardy pick high gears to show how tough they are."

How do I get started? Plan short routes of ten to 15 miles on quiet roads -- around a park, say, or on two-lane highways outside of town. Try to cycle at least three times a week, but don't think of your rides as workouts so much as sightseeing (the exercise will take care of itself). Limit your time on the bike to less than an hour, and avoid big hills for the first few months. The best way to insure your bike ends up collecting dust in the garage is to tackle more than you can reasonably handle.

When you're more comfortable on the bike, consider adding five or ten miles to your routes; also, try using your bike for trips to the store or even commuting. Riding will start to feel like second nature, and you'll find that staying in shape becomes nearly effortless.