Kate Lyden

Ph.D.

KAL Research|Consulting, PAL Technologies

Research Scientist

IDATA (Learn more about this study)

IDATA-21

Apr 16, 2018

Characterizing Free-Living Stepping Behavior

U.S. public health recommendations emphasize the importance of performing physical activities (PA) of at least moderate intensity and in bouts of at least 10 minutes. It’s been suggested that cadence (steps per minute) is an appropriate metric to identify health enhancing ambulatory behavior that meets these requirements. Assessed under laboratory conditions, cadence is strongly correlated (r=0.93) with intensity (measured by indirect calorimetry) and 100 steps per minute is considered a reasonable heuristic value associated with moderate intensity stepping. However, to date few studies have used cadence as either a measure of PA exposure and/or a behavioral outcome following an intervention or treatment. This is in part due to the challenge of measuring cadence in free-living individuals.

Pedometers have long provided a simple means to count daily steps, but lack the time-stamping technology and sophisticated algorithms necessary to estimate stepping bout duration – a component of cadence. As such, stepping recommendations have traditionally focused on total accumulation and have ignored other potentially important features of stepping behavior. For example, achieving 10,000 steps per day is a popular goal amongst researchers, clinicians and the general public. While evidence broadly supports the benefits of 10,000 steps per day for improved heart, metabolic and mental health, less is known about how the pace, duration and frequency of stepping behavior impact specific health outcomes. E.g., Does it matter if 10,000 steps/day are accumulated at a slow, meandering pace versus a brisk walk. Or if 10,000 steps/day are accumulated during a long continuous bout versus more frequent, short stepping bouts?

Wearable accelerometers are now capable of measuring the duration of individual stepping bouts, making it possible to estimate free-living cadence. However, the optimal method(s) for summarizing free-living cadence have not been identified and it is not known if/how free-living cadence is associated with health outcomes. In addition to cadence, the time-stamped nature of accelerometer output allows for investigation into the temporal dynamics (i.e., patterns) of stepping behavior.

The overall objective of this study is to characterize the stepping behavior of adult members of AARP and to determine if and how detailed metrics of stepping are associated with body composition, fitness and physical activity energy expenditure.