The activity also is inexpensive and can be performed at any time by almost everyone, he said.
Last year 14.5 million people walked for fitness two or more times a week, Fenton said.
Walking is an aerobic exercise that can condition the heart and lungs if done at the proper intensity for 30 to 60 minutes at a time at least three to four times a week, according to American Heart Association.
Regular exercise such as walking can give you more energy, improve your self image, relieve tension, help you relax and sleep, tone muscles and increase stamina.
People who don't exercise are more prone to heart attacks and poor circulation, said Kay Hoffman, Western regional director of American Heart Association.
"People who walk have a healthier lifestyle," Hoffman said.
Each year up to 250,000 deaths in the United States are attributed to a lack of regular physical activity, according to American Heart Association.
Fenton, a member of the U.S. Racewalking Team from 1986 to 1991 and a coach and clinician for walking and racewalking, sees walking as a spectrum with an after-dinner stroll at one end and competitive racewalking at the other. In between is power walking - also known by a variety of names such as aerobic walking and power striding.
Power walking is characterized by long strides, long arm swings and hip rotation, said Pat Fineagan, a biomechanics specialist at The Rehab Center at Robinwood in Hagerstown.
"If you cranked it up one iota more, you'd be jogging," Fineagan said.
You don't have to go to extremes to benefit from walking.
A brisk health walk can be realized by taking 120 to 135 steps per minute, Fenton said. That equals a speed of about 3 1/2 mph.
The biggest mistake is setting your goals too high, said Jeanni Moyer, physical therapist at The Rehab Center at Robinwood.
Aim for consistency - it's not how far you walk, but the fact that you do the activity every day, she said.
Check with your physician before beginning an exercise program, Fineagan said.
Wear nonrestrictive clothing and walking shoes that provide proper support and shock absorption, she said.
Fifty percent of injuries occur due to the lack of proper stretching, Fineagan said. She recommends a 15-minute warmup of stretching exercises, paying attention to the calves, hamstrings, heel cords, upper body and arms.
Walk this way
Use proper posture when walking, Fenton said. Tighten your abdominal muscles and look forward, not at the ground.
Take quick steps, and push off with your toes, he said. Bend your arms 90 degrees at the elbow, and swing your hands from your waistband to chest height.
A smooth walking surface is best, Moyer said. Avoid walking on grass or gravel.
Increase your speed and intensity as your program proceeds.
The amount you elevate your heart rate during an exercise determines the level of intensity of the workout and the number of calories you burn each minute.
Use some mental tricks to keep walking, Fenton said.
One is to monitor progress by keeping an exercise diary.
"Maintain a streak, and see how many days in a row you can go," he said.
Don't use the excuse that there isn't enough time.
"Convince yourself that even five minutes count," Fenton said.
Pick a time of day and stick to a schedule, Moyer said. If you walk outdoors, change your route to get different scenery.
As further encouragement, walk with a friend.
"This helps if you're not in the mood and want to slack off," Moyer said.
Reward yourself if you're doing well.
"Go to a movie, or go shopping now that your size is smaller," Fineagan said.