Temporal Dynamics Between Sleep and Physical Activity After Cardiac Surgery: A Cross-Lagged Panel Model

Cardiac patients often experience sleep problems and reduced physical activity (PA) after cardiac surgery. Sleep and PA are known to have a reciprocal interaction, but their temporal dynamic relationship remains unexplored in this population.

This study aimed to examine the temporal bidirectional relationship between sleep and PA after cardiac surgery using a cross-lagged panel model (CLPM).

This exploratory, longitudinal study involved a secondary analysis of previous data. The sample consisted of 33 adults who had undergone open-heart surgery at least 10 weeks prior. Five sleep and four PA variables were measured over 7 days using a wrist-worn ActiGraph. Data were analyzed using CLPM.

Participants (mean age = 60.8 ± 10.1 years) had undergone cardiac surgery an average of 85.7 ± 91.2 months previously. The most common surgery type was coronary artery bypass grafting. Mean total sleep time was 6.4 ± 1.2 hours, below the recommended average of 7 hours, while average moderate-to-vigorous PA (117.8 ± 70.3 min/day) exceeded US guidelines. CLPM revealed unidirectional causation between sleep and PA; improved sleep efficiency predicted higher kilocalories expended and lower sedentary time the next day, while no PA predicted subsequent sleep.

Improving sleep quality may enhance postsurgery PA, emphasizing the importance of integrated strategies targeting both behaviors in clinical and home-based rehabilitation programs. Future studies should explore the temporal dynamics between sleep and PA with a larger sample at different time points after surgery, while incorporating relevant covariates and mediators to deepen the understanding of these complex interactions.