This study measured pedometer-assessed physical activity and health behaviors in a descriptive, epidemiological study of U.S. adults. We found that adults averaged 5,117 steps per day. In general, men took more steps than women (5,340 vs 4,912 steps per day), and walking declined with age. It is interesting that these step counts are only about one-third of the values measured for men and women living in an Old Order Amish farming community in Ontario, Canada (2
). Assuming that the labor-intensive farming lifestyle of the Amish reflects that of most North Americans in the mid-1800s, this suggests a marked decline in ambulatory activity over the last century and a half.
Other countries have started to conduct studies of step counting in their residents over time. Japan, for instance, has accumulated data indicating that steps per day in Japanese residents remained constant from 1995–2003 (S. Inoue, Tokyo Medical University, personal communication, June 5, 2008). The Canadian government has already used pedometers in a nationwide sample of children and adolescents (7
), and they are planning to continue this in the future.
Recently, Tudor-Locke et al. (29
) reported on accelerometer-measured step counts in U.S. adults. They analyzed data on 3,744 individuals aged 20 years or older who took part in the 2005–06 National Health and Nutrition Examination Survey (NHANES). The participants were instructed to wear an Actigraph accelerometer with a step-count function for 7 days, and had at least 1 day of data where they wore it for at least 10 hours. U.S. adults took an average of 9,676 ± 107 steps per day, which the authors deemed too high to be reasonable. Thus, they adjusted the step data to make the results more congruent with pedometer data from previous studies of adults living in Colorado and South Carolina. They used a procedure that involved censoring (i.e.- eliminating) any steps accumulated during minutes where the accelerometer activity counts were less than 500 counts per minute. This had the effect of lowering the mean (± SE) step counts to 6,540 ± 106 steps per day. While this value is higher than what we measured in the current study, both would fall into the “low active” category (i.e., 5,000–7,500 steps per day) using the step index of Tudor-Locke and Bassett (31
U.S. Adults are Inactive
This sample of adults was less active than those from other countries. Sequeira et al. (26
) published a descriptive epidemiological study reporting in a representative population sample of 493 Swiss adults (25–74 years of age). The pedometer study was conducted in conjunction with the World Health Organization Monitoring Trends and Determinants Cardiovascular Disease (MONICA) project in April–June 1989. Ped-o-boy pedometers (Barrigo GmbH, Schwenningen, Germany) were used, and were individually calibrated to improve accuracy. The mean step counts recorded over seven days were 10,400 steps per day in men, and 8,900 steps per day in women. An age-related decline in steps per day was observed, with the oldest group taking fewer steps per day than the younger groups.
McCormack et al. (18
) studied physical activity levels of adults in Western Australia, in November-December 2002. The study participants were a sub-sample of 3,200 survey respondents taking part in a physical activity survey conducted under the auspices of the Premier’s Physical Activity Task Force of Western Australia. After completing a telephone interview, 603 out of 1,326 individuals who were asked to wear a Yamax SW-700 pedometer for seven days agreed to take part in a pedometer study (45% response rate). On average, adults in Western Australia took 9,695 steps per day, with men taking more steps per day (10,221) than women (9,178). An age-related decline in steps per day was observed.
Inoue et al. (15
) reported the results of the Japanese National Health and Nutrition Survey (J-HANES), conducted in 2003. J-HANES is an annual survey conducted by the Ministry of Health, Labor, and Welfare since 1945, and the Yamax digi-walker pedometer has been used to monitor the number of steps since 1992 (33
). In November 2003, J-HANES examined 1-day step counts in a nationally representative study of 8,867 individuals. The mean steps per day taken by Japanese residents, 15 years of age and older, was 7,168 ± 4,248 steps per day (mean ± SD), with Japanese males taking 7,575 ± 4,580 steps per day and Japanese women taking 6,821 ± 3,909 step per day. As in other countries, there was an age-related decline in steps per day.
It is important to compare the methods used in pedometer studies conducted in different nations. Most studies used random sampling techniques, which involved selection of a random sample of telephone numbers for the initial contact. Beyond that, variation existed in how members of a household were selected. In Western Australia, for example, they interviewed the person in the house who had the most recent birthday and was at least 18 years of age. In Japan, 5000 households were sampled, including 15,000 participants. (Thus, multiple individuals in some Japanese households were sampled). In the present study, the participants were members of an online panel, who agreed to participate in a survey. Thus, it is possible that there was some selection bias in our study but we attempted to control for this by weighting the data to reflect the entire United States population, according to key demographic variables.
In all of the pedometer studies, participants were given a pedometer, instruction sheet, and step diary to record their data. They were given instruction on proper placement of the pedometer and told to wear the pedometer during all waking hours. In Australia and the present study, pedometers and accompanying materials were sent out through the mail, whereas in the Swiss and Japanese studies, a physical examination was conducted and the pedometer was handed out in person. The present study used a 2-day sampling period, whereas Australia and Switzerland used a 7-day sampling period and Japan used a 1-day sampling period. In cases where the primary intent is to measure steps per day of the population, rather than individuals, we believe that 1–2 days is adequate. The time of year when data were collected also varied. In Australia, data were collected during November and December, while in Japan they were collected in November, and in Switzerland they were collected during May and June. The present study also collected pedometer data in May and June. Despite some inconsistencies, it is still possible to obtain a rough estimate of walking behaviors in different countries by using data from pedometer surveys.
In the present study, the people we examined took fewer steps per day than those in other developed nations with similar, high levels of income and standards of living. This may partially explain why the prevalence of obesity in the U.S. is higher than in other countries. Based on self-reported height and weight, the prevalence of obesity in U.S. adults was 23.9% in 2002 (1
). By comparison, Australia had an obesity rate of 16% in 2001 (5
), Switzerland had an obesity rate of 8% in 2002 (9
), and Japan had an obesity rate of 3% in 2000 (33
). (In all of these studies, obesity was defined as a body mass index (BMI) ≥ 30 kg·
and BMI was computed from self-reported height and weight.) Switzerland and Japan both have much higher rates of transportation-related walking compared to the U.S. (1
), which contributes the difference in daily step counts. In Australia, car use is almost as prevalent as in the U.S. (1
), which might suggest that many of their steps are coming from leisure-time, household, or occupational activity.
Obese Individuals are Particularly Inactive
We found that pedometer-measured physical activity is lower in obese individuals. In this study, obese individuals accumulated about 1500 fewer steps per day than those who were neither overweight nor obese. This is consistent with previous studies reporting an inverse relation between steps per day and adiposity (12
). Regardless of whether a low level of physical activity is a cause or a result of obesity, this is a real concern. Low levels of physical activity can contribute to the continuation of obesity and decreased levels of physical activity are known to be associated with increased risk of obesity, hypertension, diabetes, heart disease, some cancers, and other chronic illnesses (22
Walking to Prevent Weight Gain in U.S. Adults
Given the observed differences in physical activity between those who are obese and those who are at a healthy weight, promoting walking may be a reasonable strategy to prevent weight gain in the population. The median weight gain in U.S. adults is 1.8 lbs (or 0.8 kg) per year (13
), and this type of “creeping weight gain” is a serious problem. The accelerating rate of obesity will present a major challenge to the health care industry in the decades to come. Thus, immediate steps are needed to slow the rate of weight gain, and ultimately to reverse it.
America On the Move advocates a simple approach for prevention of weight gain in individuals (32
). The increase in physical activity advocated by America On the Move is 2,000 steps per day, or roughly one mile of walking. This could be easily achieved in about 20 minutes per day, and it would bring most Americans much closer to the average daily step counts seen in other developed nations (e.g., Switzerland, Australia, and Japan) although to close the gap entirely would require Americans to walk about 30 to 40 minutes per day. Another recommendation of America On the Move is to decrease caloric intake by 100 kcal per day. This two-pronged approach is consistent with the International Obesity Task Force’s view that the current obesity epidemic is due to physical inactivity and an abundance of inexpensive, calorie-dense foods and beverages that promote weight gain (16
To achieve 30 or more pounds of weight loss (≥ 13.6 kg) and sustain it for at least one year is likely to require considerably more effort than the initial, simple steps recommended by America On the Move to prevent weight gain, as indicated by data from the National Weight Control Registry (NWCR). Klem et al. (17
) examined 784 individuals who met these criteria, and found that they expended 400 kcal per day through physical activity (equivalent to 60+ minutes of moderate-intensity physical activity), while consuming a low-fat, calorie-restricted diet. NWCR researchers studied a small subset of individuals enrolled in the registry, and they were found to be taking 10,900 steps per day (Wyatt H, unpublished data).
Are Pedometers Useful in Promoting Physical Activity?
The present study provides supporting evidence that pedometers are helpful in promoting increased physical activity. Individuals who were already using a pedometer before enrolling in the current study were found to accumulate more steps than those who were not (6,497 vs. 5,072 steps per day). This suggests that pedometers might motivate individuals to increase their physical activity, and it is consistent with longitudinal studies showing that pedometers are effective for increasing physical activity in previously sedentary adults. A recent review concluded that pedometer-based walking programs increased participants’ activity levels by an average of 2,183 steps per day (4
). Programs that included a daily step goal and required participants to maintain a step diary were successful in increasing activity levels, while those that lacked these components were not (4
Strengths and Limitations
Pedometer studies are inexpensive, they require little data reduction, and the methodology is fairly uniform between studies. Thus, they can be used for epidemiological studies involving surveillance, tracking secular trends in physical activity, and comparing populations around the world. However, accelerometer-based activity monitors have certain advantages over pedometers in terms of being able to assess “wear time” and to detect minutes spent in light, moderate, and vigorous exercise. Furthermore, studies have shown that accelerometer-based devices are less impacted by adiposity than spring-levered pedometers (8
). For example, Crouter et al. (8
) found that the Yamax SW series pedometer undercounted steps in overweight, and obese individuals, whereas an accelerometer-based step counter (New Lifestyles NL-2000) was more accurate. Thus, the high prevalence of obesity in the United States could be contributing to an underestimation of steps per day, due to the use of this type of spring-levered pedometer.
Pedometers do not measure all types of physical activity, and it is acknowledged that they do not capture swimming, cycling, and weight lifting (3
). Nevertheless, because pedometers can measure walking, running, many incidental activities, and sporting activities that involve walking/running (e.g., most team sports, golf, tennis, aerobics etc) they are usually seen as a valid measure of ambulatory physical activity (18
). A further limitation is that participation in the study was voluntary, and it is possible that people who agreed to participate in the online survey could have different levels of activity than the general U.S. population. In addition, self-reported step counts cannot be considered a gold standard for objectively measured physical activity, since reporting bias can occur.
In the present study, the step counts for the Rocky Mountain region (6,298 steps per day) were approximately 500 steps per day less than those from a previous study of Colorado residents (6,804 steps per day) conducted by Harris Interactive, Inc. (32
). The step counts for the Southeast region (5,214 steps per day) were about 700 steps per day less than those from a previous telephone based survey conducted in Fort Sumpter, SC (5,931 steps per day) (28
). In part, these differences might have resulted from the fact that participants were recruited from Harris Interactive’s online panel, as opposed to randomly selected telephone numbers of people in those regions. However, the effect of this difference in methodology appears to be relatively small, and it does not alter the overall conclusions of the present study.
In summary, in the present study we found that adults average a little over 5,100 steps per day. Similar to studies conducted in other countries, men accumulate more steps per day than women, and there is an age-related decline in steps per day. However, the average daily step counts that we measured in men and women are lower than those seen in studies from Switzerland, Western Australia, and Japan. The results suggest that policies to promote physical activity and health eating, along with better education about making healthy lifestyle choices, are needed to counteract the obesity epidemic.