What Is Moderate Intensity Exercise?
You’ve read the recommendations:
Engage in moderate intensity cardiovascular exercise for at least 30-minutes on most days or 150-minutes a week
But what exactly is moderate intensity exercise?
That question was recently answered by researchers at San Diego State University. In looking ways to make the pedometer useful for assessing exercise intensity, they found that walking at least 100 steps per minute meets the criteria for moderate intensity exercise. That translates into 3,000 steps in 30 minutes on a flat surface.
The Magic Number
Exercise scientists typically measure oxygen intake per minute in people working out. Oxygen uptake increases when the metabolic cost of an exercise is high. (It's a fancy way to say the work is harder.) This process is expressed as a MET (Metabolic Equivalent of Task), which is a comparison of the metabolic cost of an activity to the metabolic cost of rest. For instance, the Basal Metabolic Rate, the calories burned to keep you alive - not calling for much oxygen, comes in at MET 1, whereas running madly at 10 mph has a MET rate of 18. The San Diego State scientists figured that a MET rate of 3 accounted for the oxygen uptake needed for ‘moderate’ activity. MET 3 is like walking 3 miles per hour.
Back to the Pedometer
Many people wear pedometers when they walk to count steps and measure distance. Pedometers are popular and easy to use but they do not address exercise intensity. Furthermore, for a pedometer to be accurate it must be worn vertically hooked to the waistband directly above the hip, and for distance accuracy, the stride length must be set. The best way to measure stride is to step into a puddle, walk and leave footprints, and then measure the distance from the heel of one foot to the heel of the other.
Not So Fast
Do not confuse time-limited exercise at a moderate intensity level with having an overall Moderate Level of Activity. When 3,000 steps in 30 minutes is coupled with a desk job, the overall activity level is Light at best. Calculate your Daily Calorie Expenditure at Calorie Count.
And finally, many people are quite out-of-shape. They are easily winded and reach maximum exertion with much less than 100 steps per minute. If that is you, downgrade your speed and train to go into training. It is always safe to get medical clearance before you start to exercise.
Simon J. Marshall et al. Translating Physical Activity Recommendations into a Pedometer-Based Step Goal: 3000 Steps in 30 Minutes. American Journal of Preventive Medicine, Volume 36, Issue 5 (May 2009)
Do you walk 100 steps per minute?