Researchers are now suggesting people to walk 150 minutes a week, which is equivalent to 30 minutes each day 5 times a week, though moderate physical activity is known to be beneficial to health.
Researchers at the School of Exercise and Nutritional Sciences, San Diego State University, point out that pedometers widely used as a physical activity monitoring tool are unable to measure activity intensity.
They have determined that a rate of at least 100 steps per minute achieves moderate intensity activity.
According to them, a simple pedometer-based recommendation of 3000 steps in 30 minutes can get people started on a meaningful exercise program.
The researchers monitored 58 woman and 39 men for oxygen uptake while walking on a treadmill. The subjects completed 46-minute sessions at different treadmill speeds between 65 and 110 meters per minute.
All subjects wore pedometers, and their heart rates were recorded.
The research team used 3 METs, or metabolic equivalents, as the minimum level of oxygen demand which approximates moderate exercise, to monitor the participants in order to determine whether they had reached the moderate-exercise level at a given treadmill speed.
From these data, the researchers found that for men, step counts associated with walking at 3 METs were between 92 and 102 steps per minute.
For women, according to them, the range was between 91 and 115 steps per minute.
Lead investigator Dr. Simon J. Marshall, School of Exercise and Nutritional Sciences, San Diego State University, said: "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. Because health benefits can be achieved with bouts of exercise lasting at least 10 minutes, a useful starting point is to try and accumulate 1000 steps in 10 minutes, before building up to 3000 steps in 30 minutes. Individuals can monitor their progress using a simple pedometer and a wristwatch. The use of a single and simple pedometer-based guideline that is easy both to remember and measure may be more effective in a health communication strategy than the promotion of multiple guidelines and, therefore, messages."
The study has been published in the American Journal of Preventive Medicine.