As our measurements and metrics in medicine proliferate and multiply, it is exceedingly tempting to think that our increased ability to measure correlates directly with an increased ability to care or cure . . . but is this really the case?

It’s been reasonably well established that just doing a test to “rule out” a condition does not actually provide much assurance to patients. Testing to reassure offers little reassurance. 

However, on the other side of that supposition lies the even more important question of whether testing to diagnose actually provides assurance or motivation. Two recent items of medical news caught my attention, and their divergent findings from divergent methods are worth noting.

Despite the fact that we can now routinely calculate body mass index (BMI) using electronic tools during consultations, a recent study found that, at least in the care of children, routine BMI surveillance during office visits and counseling on physical activity have little impact on (the very important problem of) childhood obesity. The authors conclude that there is a need for “the development of novel approaches for providers to address this problem.”

Conversely, programs such as the “Daily Mile” may provide a wide range of health benefits, including improved sleeping, better eating, improved fitness, and improved happiness. While I’ve been unable to locate so far any publications of research on the “Daily Mile” program, a similar school based intervention in Oklahoma led to improved BMI measurements for boys, and at least stable BMI measurements for girls.

We need to remember that in medicine the point of measurement is to help answer a question—measurement in and of itself does not do much of anything. So, when it comes to being healthy and pursuing a healthy lifestyle, the most beneficial actions have little or nothing to do with measurement. Rather the most important interventions have to do with action.

Being healthy is about . . . being healthy. Measurements may tell us things, but actions help us change things. Action may involve programs and group interventions, or it may be a matter of helping our patients find their own internal motivations.

Either way, the failures of BMI measurement and the apparent successes of the Daily Mile are good reminders of the aphorism: “Don’t just sit there (and measure), do something (go for a run)!”

William E Cayley Jr practices at the Augusta Family Medicine Clinic; teaches at the Eau Claire Family Medicine Residency; and is a professor at the University of Wisconsin, Department of Family Medicine.

Competing interests: “I declare that I have read and understood BMJ policy on declaration of interests and I have no relevant interests to declare beyond my enjoyment of running!”