1. We've become a nation of nonwalkers.

Feeling sluggish? Caught up in the roll-out-of-bed, drive-to-work, sit-at-the-computer lifestyle? Having one of those 3,000-steps-a day kind of days? Join the crowd. Over the past 20 years, the frequency with which people walk for exercise has dropped by 42 percent, according to the Cleveland Clinic. Over that same period, the number of overweight Americans has increased by 40 percent.

2. Reversing the trend is not so hard.

The U.S. Surgeon General suggests 30 minutes of daily moderate activity (above and beyond standard activity). That translates roughly into 3,000 to 4,000 extra steps a day, according to the Walking Research Laboratory at Arizona State University. We normally walk about 5,000 to 6,000 steps in a day, so if you add 3,000 to 4,000 steps to that, you're at 10,000 steps a day — a level of activity that can help prevent weight gain, lower "bad" cholesterol and reduce the risk of developing high blood pressure. Most people who are walking fewer than 5,000 steps a day are gaining weight and losing muscle, researchers say.

3. Walking keeps you from adding fat.

Proven results: 30 minutes per day of walking — the equivalent of walking 10 to 12 miles per week — can prevent weight gain in most people who are physically inactive, according to a Duke University study. Even with no change in diet, participants lost weight, decreased waist sizes and increased lean body mass.

4. You can spread out the activity.

Other good news: The recommended 30 minutes of purposeful walking a day doesn't have to be achieved at once. The same benefit is derived in 10-minute increments, say researchers at Arizona's Walking Research Lab.

5. Walking fights diabetes.

The latest benefit: People with type 2 diabetes may lower their risk of heart disease by committing to a daily walk, according to a study in Japan published in the October issue of the International Journal of Sports Medicine.