Level Walking -- No Incline
Moderate walking pace is defined as walking at a rate of at least 100 steps per minute on flat, level ground or on a treadmill that is set to zero incline. This is equal to about 3 miles per hour.
To count out 100 steps, you can keep track by counting as you walk -- left, right equals two steps -- or use a pedometer. Walking at this pace means you'll take about 3,000 steps during a 30-minute walk. Setting the treadmill to about 3 mph is an easier way to ensure that you're getting enough moderately paced exercise.
Slower Speed -- Slight Incline
Researchers at Colorado State University studied the effects of walking less than 3 mph at a slight incline. Doing so yielded similar metabolic benefits with less risk of injury for obese adults. The increased resistance kept caloric burn up but decreased strain on joints and subsequent risk of musculoskeletal injury. And with less pain and injury, researchers believe that walkers might be more likely to stick to an exercise regimen.
Indicators of Moderate Exercise
Your perceived exertion is another indicator of how hard you're working when you're walking. MayoClinic.com describes moderate-intensity exercise as an increase in your respiration rate, development of light sweat after 10 minutes of activity, and the ability to carry on a conversation while walking. Let your body be your guide. If moderate-level activity causes pain or distress, slow down. It's better to start with light exercise and increase the pace and intensity gradually.