Physical Activity Declines over a 12-Month Period in Parkinson’s Disease: Considerations for Longitudinal Activity Monitoring

ABSTRACT Purpose The purpose of this project was to evaluate physical activity trends in individuals with Parkinson’s disease (PD) over a 12-month period using continuous activity monitoring. Environmental (temperature) and cultural factors (represented by day of the week) were evaluated as potential external sources of variability. It was hypothesized that physical activity would decline over the course of 12 months. Further, it was hypothesized that participants would exhibit greater physical activity on warmer days and that the day of the week would have minimal impact on physical activity as many participants were no longer in the workforce. Methods Participants were part of the Usual and Customary Care arm ( N = 119) of the CYClical Lower Extremity Exercise Trial for Parkinson’s disease-II (CYCLE-II) at the Cleveland Clinic and University of Utah. Participants wore a Garmin Vivofit4® device daily for 12 months. A linear mixed effects model was created to model daily steps over 12 months. Results Participants wore their activity monitors on 93% of study days. Steps per day declined by 6.1% over 12 months (95% confidence interval, 12.6% decline, 0.9% increase; P = 0.09). Steps per day were greater with warmer temperatures ( P < 0.001), plateauing and declining between 75°F to 85°F (24–29°C). Participants took fewer steps on Sunday; this daily difference was more pronounced for Utah participants, who took 25% fewer steps on Sundays compared with other weekdays ( P < 0.001). Conclusions Most individuals live with PD for decades, and interventions should address the expected annual decline in daily step count. Environmental and cultural factors impact daily step count and should be adjusted for in short- and long-term monitoring of physical activity in individuals with PD.