First Steps Into the Brave New Transdiscipline of Mobile Health.

Given substantial evidence that healthy lifestyle behaviors lessen the odds of cardiovascular disease, the AHA/ACC 1 Guidelines advise physicians to foster patients’ physical activity. But how is the clinician to evaluate the patient’s healthy lifestyle behaviors, let alone enhance them? Traditionally, patient self-reports supplied nearly all behavioral data available to health professionals. Whether given by free recall, structured questionnaire, or written logs, however, post hoc surveys suffer from forms of error well-known to behavioral scientists. People forget. Many have no idea what moderate-to-vigorous activity feels like. Individuals also experience demands and motivations that distort what they report. For a long while, not much could be done to increase confidence in the validity of behavioral assessments. Although one could observe peoples’ behavior objectively in controlled laboratory conditions or experimental tasks, legitimate questions arose about whether people would behave the same way in real life as they had in the laboratory. This state of affairs began to change in the 1980s when acceleration signals from a worn sensor first were used to measure physical activity. 2