For real health benefits, people should exercise for 30 minutes a day five times a week, a new study has found.
Although pedometers (which measure how much we walk) are widely used as a physical activity monitoring tool, they are unable to measure activity intensity. Researchers have determined that a rate of at least 100 steps per minute achieves moderate intensity activity.
Therefore a simple pedometer-based recommendation of 3,000 steps in 30 minutes can get people started on a meaningful exercise programme.
While being monitored for oxygen uptake during walking on a treadmill, 58 women and 39 men completed four to six-minute sessions at different treadmill speeds between 65 and 110 metres per minute.
All wore pedometers and their heart rates were recorded. Using 3 METs, or metabolic equivalents, as the minimum level of oxygen demand which approximates moderate exercise, participants were monitored 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 three METs were between 92 and 102 steps per minute. For women, the range was between 91 and 115 steps per minute.
Lead investigator Simon J. Marshall, School of Exercise and Nutritional Sciences, San Diego State University (SDSU), 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 1,000 steps in 10 minutes, before building up to 3,000 steps in 30 minutes, said a SDSU release.
Individuals can monitor their progress using a simple pedometer and a wristwatch.
The study is scheduled for publication in the May issue of the American Journal of Preventive Medicine.