Like most people, I used my pedometer passively to note how many steps I took each day. Now I use it as a prod for better performance and to help control my diabetes.
We can use pedometers to motivate us to get enough of the moderate-intensity physical activity we need. The government’s official 2008 Physical Activity Guidelines for Americans, which I covered here last year, calls for us to get a minimum of 150 minutes of this moderate-intensity exercise each week. That can work out to 30 minutes on five days of the week. We can also get it in shorter bouts, typically of 10 minutes each time.
But many of us can’t figure out what “moderate-intensity” means. Until I read a brand new research report, I certainly didn’t.
This new study, led by exercise and nutritional sciences professor Simon J. Marshall at San Diego State University, determined that a rate of at least 100 steps per minute will usually let us achieve moderate-intensity activity. The study, “Translating Physical Activity Recommendations into a Pedometer-Based Step Goal,” will appear in the May 2009 issue of the American Journal of Preventative Medicine. Not even the abstract is online yet, but the journal provided me with the full-text of the article.
Dr. Marshall and seven associates based their findings on a community sample of 97 adults. The participants in the study were typically quite overweight with a mean BMI of 29.
The participants used pedometers to count their steps. But few pedometers can measure the intensity of our activity. The solution, however, was simple — timing the exercise.
For both men and women about 100 steps per minute provides minimally moderate-intensity activity as defined by three METs. As I wrote here in July, MET, which is short for metabolic equivalent, is a technical concept that we need to understand.
This works out to walking at 100 steps per minutes on level terrain. Or 3,000 steps in 30 minutes each of five days of the week.
The old standard, dating from 1993, is 10,000 steps per day. It’s one that I have tried on the average to meet. But it is “based on limited evidence, may be unrealistic for many people, and does not incorporate activity intensity,” the report says.
Still, counting steps with a pedometer does help. A recent meta-analysis shows that when we use one just to count our steps, we increase our level of physical activity by 27 percent. We also significantly decrease our BMI and blood pressure.
While I have had — and lost — many pedometers, I really like my tiny Omron HJ-303 that I got at the local REI. It’s small enough to keep in a pocket of my trousers all the time. It’s also accurate whether horizontal, vertical, or flat.
It is one of the few pedometers that calculates how many steps we take at a level of three METs, and it tells time. But much more convenient to check the time is using it with my iPod Touch. It (as well as an iPhone) has stopwatch that I set yesterday to interrupt the song I was playing when my 30 minutes was up.
Normally, I am much more of a tortoise than a hare — a long rather than a fast walker. So I wondered if I could walk at moderate intensity. I chose one of my favorite level trails, one that doesn’t have a lot of rocks that would slow me down. While I took my camera as I always do on a hike, I determined not to use it unless I saw something extraordinary, and I didn’t. I also didn’t do any interval training, no jogging or running. I just walked at a comfortable speed, albeit faster than normal.
When my iPod told me that 30 minutes were up, I was pleasantly surprised that I had walked 3,190 steps. That’s certainly moderate intensity and a level that I would not have achieved without this prodding.
HealthCentral published an earlier version of this article.