March 17, 2009 -- What exactly is moderate exercise? A new study suggests the much-touted moderate-intensity walk should translate to about 100 steps per minute, or 3,000 steps in 30 minutes.
Federal exercise recommendations call for Americans to get at least 150 minutes per week of moderate exercise for optimal health. And some studies have suggested that moderate-intensity exercise -- like walking -- may be just as beneficial as more vigorous exercise.
“This presents a challenge because health benefits are dependent on the intensity of activity, yet there are few valid and reliable monitoring tools available to the public that are affordable and easy to use,” researchers write in the American Journal of Preventive Medicine.
In their study, researchers sought to translate the moderate-exercise recommendations into easily achievable targets that could be measured using a common pedometer.
Measuring Moderate Exercise
Although pedometers are widely used to measure physical activity by counting the number of steps a person takes, they can’t measure exercise intensity.
In the lab, exercise intensity is commonly determined by measuring the amount of oxygen taken in by the body during exercise, known as oxygen uptake.
To see how many steps per minute were needed to achieve moderate-intensity exercise, investigators monitored oxygen uptake in 58 women and 39 men while they completed four different 6-minute sessions on the treadmill at speeds ranging from 2.4 to 4.1 miles per hour. All of the participants also wore pedometers during the exercise sessions.
The results showed that for men the number of steps per minute to reach moderate-intensity exercise was between 92 and 102. For women, the range was between 91 and 115 steps per minute.
"We believe that these data support a general recommendation of walking at more than 100 steps per minute on level terrain to meet the minimum of the moderate-intensity guideline,” researcher Simon J. Marshall, PhD, of the School of Exercise and Nutritional Sciences at San Diego State University, says in a news release.
“Because health benefits can be achieved with bouts of exercise lasting at least 10 minutes, a useful starting point is to try and accumulate 1,000 steps in 10 minutes, before building up to 3,000 steps in 30 minutes,” he says. “Individuals can monitor their progress using a simple pedometer and a wristwatch.”