100 Steps A Minute Qualifies As Moderate Exercise, Study

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Main Category: Sports Medicine / Fitness
Article Date: 17 Mar 2009 - 12:00 PDT

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Researchers in the US investigating what is meant when studies suggest that moderate physical activity is beneficial to health and wellbeing concluded that moderate intensity means walking at a speed of at least 100 steps per minute on level ground; they came to this view after observing men and women completing a range of exercises.

The study was the work of lead investigator Dr Simon J. Marshall, of the School of Exercise and Nutritional Sciences at San Diego State University, and colleagues, and is to appear in the May 2009 issue of the American Journal of Preventive Medicine, which is published by Elsevier.

We have known for some time that moderate physical activity is good for our health and wellbeing, and many studies bear testimony to the benefits of doing at least 150 minutes of such exercise every week, preferably as 30 minutes a day for 5 days of the week.

Many people use pedometers to manage their daily exercise, but while they are easy and useful for measuring distance, they don't tell you about the intensity of the physical activity. As a result of their investigation, Marshall and colleagues suggest that if you use a pedometer as your daily exercise monitor, then aim for 3000 steps in 30 minutes to make sure you hit the "moderate" level of physical activity that is necessary for health.

For the study, Marshall and colleagues monitored 58 women and 39 men while they walked on treadmills. They measured their oxygen intake while they walked for 4 to 6 minutes at a time at different treadmill speeds from 65 up to 110 meters a minute.

The participants also wore pedometers and heart rate monitors. They had to aim for a metabolic equivalent (MET) rate of 3, which is considered to be about the right level of oxygen intake for moderate physical activity (the MET rate shows on the treadmill when you put in your weight; when you walk at a MET rate of 3, this means you are using about three times as much energy as when you are resting; jogging is about 8 METs, while sprinting ranges from 12 to 18).

The researchers monitored the participants to see how many steps per minute they had to walk at to reach their 3 METs target. They found that the men reached the 3 METs level at a step count of 92 to 102 steps per minute and the women at 91 to 115 steps per minute.

A main finding was that pedometers are not a very reliable way to determine if you are walking at the right intensity to reach 3 METs (only 50 per cent of the participants were correctly classified as walking at moderate intensity using step rate alone). However, because they are such a simple device to use, the authors suggest they are still useful as a way to meet exercise guidelines, if you aim for above 100 steps a minute.

The researchers also said that a useful way to start with a pedometer is to accumulate 1000 steps in 10 minutes, because this is the minimum exercise time for producing health benefits. Then, when that pattern is well established and achievable, try to reach 3000 steps in 30 minutes, for which you only need a pedometer and a wristwatch.

As Marshall explained:

"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."

There is also the advantage, if you want to exercise outside on a sunny day and reach your moderate exercise level, that it is easier (and more pleasant) to take a pedometer and wristwatch with you than it is to drag a treadmill into the garden.

"Translating Physical Activity Recommendations into a Pedometer-Based Step Goal: 3000 Steps in 30 Minutes."
Simon J. Marshall, Susan S. Levy, Catrine E. Tudor-Locke, Fred W. Kolkhorst, Karen M. Wooten, Ming Ji, Caroline A. Macera, and Barbara E. Ainsworth.
American Journal of Preventive Medicine, Volume 36, Issue 5 (May 2009).

Click here for American Journal of Preventive Medicine.

Sources: Elsevier Health Sciences.

Written by: Catharine Paddock, PhD
Copyright: Medical News Today
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