What Is Moderate Exercise?

Recommended Moderate Exercise Equals About 100 Steps Per Minute. The results showed that for men the number of steps per minute to reach moderate-intensity exercise was ….Full Story:

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.

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.”

To stay in decent cardiovascular shape, the government and various health organizations recommend 30 minutes of “moderate intensity” exercise five days a week. But just how much exercise is that?

The old disco favorite “Stayin’ Alive” by the Bee Gees has a beat almost perfectly matched to the minimum, 100-steps per minute it takes for a half hour of proper cardio exercise. That’s 3,000 total steps, according to Simon J. Marshall, Ph.D., of San Diego State University, and colleagues.

Although a widely accepted goal of 10,000 steps per day can help people increase their physical activity, health benefits are also tied to the intensity of activity, which is difficult for patients to gauge, the researchers said.

The same problem arose for CPR trainers trying to teach the rhythm of cardiopulmonary compression. To keep up the aggressive pace needed, the Bee Gees’ 103-beat-per-minute song is informally recommended as a guide by the American Heart Association.

It’s a coincidence that the same pace is needed for moderate intensity walking, although it’s no surprise that these mnemonics are effective, Dr. Marshall said.

His group hit the gym to objectively determine a pedometer-step rate that would produce an exertion of 3 METs (metabolic equivalents) — considered the minimum for moderate-intensity exercise.

The researchers studied a community sample of 97 Latino adults who walked for six minutes on a level treadmill up to four times, at speeds increasing from 2.4 to 4.1 mph, all the while hooked up to pedometers, heart rate, and exhaled gas monitors. The participants had an average age of 32.1 and were predominantly sedentary and either overweight or obese (mean body mass index 27.5 kg/m2 for men and 29.7 kg/m2 for women).

The minimum pace associated with walking at 3 METs for men ranged from 92 to 102 steps per minute depending on the analysis method. Women likewise needed to walk at a pace of 91 to 115 steps per minute to achieve moderate intensity exercise criteria.

These findings supported a general recommendation of walking at a pace of at least 100 steps per minute on level terrain, the researchers said. This would equate to at least 3,000 steps in 30 minutes or 1,000 steps in 10 minutes three times per day to meet the minimum of the moderate-intensity guideline, which Dr. Marshall described as a brisk pace that would still allow conversation.

However, the investigators cautioned this recommendation should be used as a heuristic rather than a precise criterion given the considerable error found when using pedometer steps to measure METs.

In the three different analytic models, steps per minute explained 15% to 41% of the variance in calorimetry-measured energy expenditure.

Only 50% to 60% of individuals were correctly classified as walking at moderate intensity using the step rate alone, a success rate which Dr. Marshall described as little better than chance.

The relatively small variation in step rates needed for moderate intensity walking between gender and body mass index groups didn’t support different recommendations for these subgroups, they said.

The authors noted that “pedometers are limited as physical activity measurement devices because they capture movement only of the lower body in the vertical plane and cannot distinguish between walking on different gradients.”

Practice Pearls:

• Explain to interested patients that the Department of Health and Human Services, American Heart Association, and other organizations recommend 150 minutes of moderate-intensity exercise per week, the equivalent of 30 minutes on five days per week.

• Inform patients that walking can meet the criteria for moderate intensity exercise if the pace is brisk, approximately 100 steps per minute, according to the study.

The recommendations were reported in the May issue of the American Journal of Preventive Medicine.
Marshall SJ, et al “Translating physical activity recommendations into a pedometer-based step goal: 3000 steps in 30 minutes” Am J Prev Med 2009.

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DID YOU KNOW:
Old Age Begins at 27: New research suggests that old age actually begins even before we hit the ripe old age of 30. The research, done at the University of Virginia, indicates that our mental abilities begin to decline from the age of 27, after reaching a peak at 22. The researchers studied 2,000 men and women aged 18 to 60 over a seven year period. The people involved, mostly in good health and well-educated, had to solve visual puzzles, recall words and story details and spot patterns in letters and symbols. The research, found that in nine out of 12 tests the average age at which the top performance was achieved was 22.

The first age at which performance was significantly lower than the peak scores was 27 — for three tests of reasoning, speed of thought and spatial visualization. Memory was shown to decline from the average age of 37. In the other tests, poorer results were shown by the age of 42. The results suggested that therapies designed to prevent or reverse age-related conditions may need to start earlier, long before people retire. Neurobiology of Aging, March 2009