Trial Information

IMPACT: Inactivity Monitoring and Physical Activity Controlled Trial

Inadequate physical activity and extended bouts of sedentary time are prevalent in adults,
increasing from middle age into older adulthood. Even small changes in behavior, such as
standing or walking in place periodically to break up sedentary bouts, can have large
effects on cardiometabolic risk factors. Pedometer-based walking interventions have
demonstrated effectiveness in increasing physical activity in this population, but these
interventions have not targeted sedentary behavior. Recent technological advances have
produced activity monitors that are capable of intervening on both behaviors. These
wrist-worn monitors provide feedback and motivation for walking as well as cues to action in
the form of idle alerts. These idle alerts vibrate when the wearer has remained sedentary
for an extended period of time. Several preliminary studies have shown that older adults are
willing to break up their sedentary time if prompted, but interventions thus far have relied
upon television commercials as a cue to action. Use of these monitors would allow idle
alerts to occur throughout the day, not only during television watching periods. The purpose
of the IMPACT study (Inactivity Monitoring and Physical Activity Controlled Trial) is to
investigate the feasibility of using activity monitors to simultaneously target both
physical activity and sedentary behavior. First, we will conduct a pre-pilot test (N = 10)
over six weeks. This brief study will provide basic feasibility and acceptability
information on the monitor, content for weekly sessions, and assessments. Results will be
used to refine the intervention for use in a larger pilot two-arm randomized controlled
trial (N = 20, 12 weeks). This trial, comparing the intervention to a wait-list control
group, will test feasibility, acceptability, and health, behavioral, and psychological
outcomes. The primary outcome will be physical activity, operationalized as
objectively-measured minutes of moderate-vigorous intensity physical activity over seven
days (SenseWear armband). We will also measure cardiorespiratory fitness, physical function,
body composition, and psychosocial variables such as autonomous motivation. The results of
this innovative project will provide a foundation for future intervention in sedentary
behavior and potentially create a large public health impact in a population at unique risk.