Short-Term Effects of a Self-Monitoring-Based Intervention on Prolonged Sedentary Behavior in Older Adults With Cardiovascular Conditions: An Exploratory Secondary Analysis of a Randomized Controlled Trial

Background and Purpose: This study was an exploratory secondary analysis of data from a previously conducted randomized controlled trial (RCT) involving older adults receiving long-term care (LTC). The present secondary analysis explored the effects of an accelerometer-guided self-monitoring intervention on prolonged sedentary behavior (≥ 30 min) and physical activity in older adults with cardiovascular conditions. Methods: This exploratory secondary analysis used data from an RCT conducted at a Japanese daycare center (October 2022–January 2023). The parent RCT included 52 participants (26 in the intervention group and 26 in the control group). Of these, 36 participants with cardiovascular conditions were eligible for the present exploratory secondary analysis (intervention, n = 21; control, n = 15). The main outcome was prolonged sedentary behavior accumulated in bouts of ≥ 30 min. Other outcomes included daily step count, sedentary behavior in bouts of ≥ 1 and ≥ 60 min, sedentary bout counts and break counts, physical activity intensity, and EQ-5D-5L utility scores. Outcomes were analyzed using linear mixed-effects models. Results: Thirty-three participants with available baseline outcome data were included in the analyses (intervention, n = 19; control, n = 14). Significant group × time interactions were observed for step count, sedentary behavior in bouts of ≥ 1 min and ≥ 30 min, sedentary bout counts, and light physical activity (p < 0.05). Moderate-to-vigorous physical activity and EQ-5D-5L utility scores did not change significantly. Discussion: Accelerometer-guided self-monitoring may influence prolonged sedentary behavior and physical activity in older adults with cardiovascular conditions receiving LTC. These findings provide preliminary, hypothesis-generating evidence that self-monitoring may represent a promising approach to reducing prolonged sedentary behavior in older adults receiving LTC. Confirmation in adequately powered RCTs is warranted. © 2026 John Wiley & Sons Ltd. All rights reserved, including rights for text and data mining and training of artificial intelligence technologies or similar technologies.