Walking is the most popular exercise in the country, and its popularity is growing by leaps and bounds. Walking is low-impact and low-risk, and its health benefits have been proven in numerous studies. One study of 13,000 people found that those who walked 30 minutes a day had a much lower risk of premature death than those who rarely exercised.

A regular fitness walking program can help reduce blood cholesterol, lower blood pressure, increase cardiovascular endurance, boost bone strength, burn calories and keep weight down. To start, all you need are comfortable shoes and the proper clothing.

Layering clothing is a good idea for outdoor walking. A tight under-layer will help keep body heat in while outer layers will absorb sweat. Products such as Dri-Fit and Under Armour's Heat Gear and Cold Gear can help make a walk in less-than-perfect weather conditions much more bearable. Shoes specifically designed for walking are also a must. Plan to spend at least $75 on walking shoes or cross-trainers.

Every walk should begin with a brief warm-up. A warm-up should be a low-intensity version of the rest of your walk. Walk slowly in the environment you will be working out in. If you are on an indoor track, take a few laps at a slower pace just to raise the body temperature and warm the muscles. If you are planning on walking outside, make sure to do your warm-up there. It's not good to warm up inside and then suddenly increase your pace when you're entering a different air temperature at the same time.

Stretch after your walk. Your muscles are much warmer afterwards and more ready to stretch. Stretches should include not only your legs but also your back, shoulders, neck and arms.

To begin your fitness walking program, walk short distances. Start with a five-minute stroll and gradually increase your time. Do not feel that you have to increase your time by even increments; rather, take your previous time and add about 4 percent to it.

Forget about speed at the beginning of your program. Eventually, speed can be a great intensifier, but for now, work on building your time. The American Council on Exercise recommends 60 to 90 minutes of cardio exercise daily. Strive to reach that mark eventually.

Focus on your form as you walk. Bad form can make you uncomfortable or even injured. Keep your head lifted and your shoulders relaxed as you walk. Try to pull your abdominal muscles toward your spine (meaning, suck in your belly). Swing your arms naturally and breathe deeply. If you can't catch your breath, slow down and avoid hills.

Avoid using hand weights or leg weights to increase the intensity of your walk. They only add a minor benefit, and they increase your risk of injury by up to 85 percent.

Test your intensity throughout the walk by using the "talk test." If you can breathe well enough to sing a song, you probably aren't working hard enough. If you have to stop and catch your breath to carry on a conversation, you're likely working too hard. If you can carry on a conversation in between breaths, you are probably working at the right pace.

Once you have reached a point where you can walk a few miles with ease, you should start to vary your intensity. Walking hills is a great way to do this. Concentrate on lengthening your stride to increase your speed.

If you find walking to be boring, listen to lively music while you walk. For safety reasons, keep your headset volume low enough to hear traffic, and always be aware of your surroundings.