Annals Journal Club: Pedometers for Promoting Walking and Weight Loss

Does it strike anyone else as odd that when a research intervention involves physical activity, the dependent variable is weight loss?

We know that physical fitness, as measured by peak METs achieved, is inversely correlated with all-cause mortality. So why don't investigators use a measure of fitness, rather than a very indirect proxy in the form of weight loss?

The answer is that there is no "vital sign" for fitness. Weight is easy to measure. Fitness is difficult. It's time to stop pretending, and measure fitness directly.

The Finns showed us how to do it with their 2 kilometer walk test. The Rockport walk test (1 mile) has been extensively researched in the US and found to be a reliable measure of fitness.

The Kansas Department of Health and Environment, with support from the Kansas Medical Society and the Kansas Academy of Family Physicians, is backing the "What's Your Mile?" initiative as a fitness vital sign.

Information can be found on the Healthy Kansas website, http://www.healthykansas.org/whats_your_mile.aspx.

The timed one-mile walk can be self-administered by patients, and would serve as a reliable research tool for what we really want to measure.

Competing interests:   None declared

The authors report a relationship between pedometer use and weight loss in a meta-analysis. While the weight loss is considered to be “modest”, any weight loss should be considered a valuable outcome. Given that the research shows that on average people gain 0.5 kg. per year (Brown, Williams, Ford, Ball, & Dobson, In press), interventions that counter this accumulation of weight is extremely beneficial. In fact, individuals might become more successful sustaining weight loss, compared to the poor long-term outcomes we’ve seen (Mann & et al., 2007), if healthcare providers and researchers could help people set more modest weight loss goals.

One question this paper doesn’t answer is whether pedometers continue to be effective motivational tools after the support from the structured interventions disappears. Pedometers might be effective for increasing physical activity and losing modest amounts of weight during an intervention but do they continue to function in this way after the formal intervention period ends? It may depend upon whether people experience achieving their pedometer goals as extrinsic (e.g., “I’m fulfilling the duties of the study I signed up for”) or more intrinsic (e.g., “I feel better from this extra walking.”) There is research on motivation suggesting that extrinsic motivation is much less effective for long-term behaviorial pursuits compared to intrinsic motivation (Deci & Ryan, 2000). Thus, healthcare practitioners might help patients develop a more intrinsic orientation to any pedometer use by focusing them on any physical experiences that can be experienced, such as sense of well-being or stress reduction (Segar, Eccles, Peck, & Richardson, in press).

The meta-analysis also raises another interesting question. These studies ostensibly told their study participants that they wanted the participants to increase the amount they walked, but did not focus them on losing weight. From a motivational perspective, it may be that instead of focusing individuals on a weight-loss outcome, we should rather focus them on, and give them tools to, successfully integrate the behaviors underlying weight control (e.g., physical activity). Data suggest that shifting women’s goals for exercising away from weight-related reasons produced increased physical activity that was sustained over time, on average 10 months after the program had ended (Segar, Jayaratne, Hanlon, & Richardson, 2002). In fact, a soon-to-be released study reported that women who exercise mainly to lose weight have participate in the least amount of physical activity, even after controlling for BMI (Segar et al., in press).

Brown, W., Williams, L., Ford, J., Ball, K., & Dobson, A. (In press). Identifying the "energy gap": magnitude and determinants of five year weight gain middle-age women. Amerian Journal of Clinical Nutrition. Deci, E. L., & Ryan, R. M. (2000). The "what" and "why" of goal pursuits: Human needs and the self-determination of behavior. Psychological Inquiry, 11(4), 227-268. Mann, L., & et al. (2007). Dieting does not work. American Psychologist. Segar, M. L., Eccles, J. S., Peck, S. C., & Richardson, C. (in press). Midlife women's physical activity goals: Sociocultural influences and effects on behavioral regulation. Sex Roles. Segar, M. L., Jayaratne, T., Hanlon, J., & Richardson, C. (2002). Fitting fitness into women’s lives: Effects of a gender-tailored physical activity intervention. Women's Health Issues, 12(6), 338-349.

Competing interests:   I coach women to change their mindset toward exercising so they will stay motivated over time with a program called EssentialSteps.