Background/Purpose: : The physical activity (PA) guidelines issued by the US Health and Human Services (HHS) recommend that adults with arthritis should perform at least 150 min/week of PA at moderate or higher intensity spread in bouts of at least 10 minutes of PA. Although it has been extensively discussed that physical inactivity is a problem among adults with arthritis, relatively little is known about the pattern of their daily activities measured in real-time by an accelerometer-based monitor. The purposes of this study were (1) to characterize the time that adults with arthritis spent in daily activities of various intensity levels and (2) to examine whether adults with arthritis meet the PA recommendations from the HHS guidelines. 

Methods: Adults with rheumatoid arthritis (RA) and with end-stage knee osteoarthritis post total knee replacement (TKA) participated in this cross-sectional study. The SenseWear Armband (Bodymedia, Pittsburgh, PA) was used to measure PA. Subjects wore the Armband for a period of 7 days, 24 hours a day. PA was characterized as the time spent per day in sedentary (0 to 0.99 metabolic equivalent [MET]), light (1 to 1.99 MET), lifestyle (2 to 2.99 METs) and moderate (3 METs and above) intensity activities. We also calculated the number of 10-minute bouts of moderate activity per day for each subject. Subjects who performed 15 bouts of moderate PA per week were considered to meet the HHS guidelines. Disability in subjects with RA was measured using the Health Assessment Questionnaire (HAQ) and in subject post TKA it was measured by the Western Ontario and McMaster Universities Arthritis Index (WOMAC). Descriptive statistics were run for the demographics, biomedical and PA data.

Results: Complete data were obtained in 68 subjects post TKA and 100 subjects with RA. Descriptive statistics are depicted in the Table. In general, our sample consisted of mainly females who were well educated. Subjects post TKA appeared to be older and heavier than subjects with RA. In general, both groups presented with mild to moderate disability. The results indicated that around 16 hours a day were spent in sedentary, 3 hours in light, 2 hours in lifestyle, and 30 minutes in moderate activities. From the 30 minutes in moderate activity dispersed throughout the day, subject performed only 1 bout of 10 minutes of continuous moderate activity per day. Only 12% of subjects with RA and 12% of subjects post TKA met the HHS guidelines. Subjects post TKA had similar pattern of activities in comparison to subjects with RA. 

Conclusion: According with the HHS guidelines, adults with arthritis in this study were in general sedentary. Only a small proportion (12%) met the HHS guidelines.  Subjects post TKA and subjects with RA seem to have similar PA behavior.