Does the volume of physical exercise influence sleep quality in patients with fibromyalgia?

Objective: To investigate the association between the volume of exercise and the quality of sleep in patients with fibromyalgia.

Methods: This is a cross-sectional study carried out from 2010 to 2019 in patients over 18 years old from the research project at a university in Brazil. Instruments related to sociodemographic and clinical characteristics, physical exercise, and the Pittsburgh Sleep Quality Index (PSQI) were applied. Participants were classified as inactive, insufficiently active, or active. In the statistical analysis, the Kruskal-Wallis and Mann-Whitney U tests were used. Binary logistic and multinomial regression were also performed.

Results: The majority of participants were physically inactive and had poor sleep quality; 68.3% with poor sleep quality were inactive. In the analysis of the difference between the three groups, sleep latency (time it takes to fall asleep) (p=0.00) and total PSQI (p=0.04) were significantly different. When the analysis was performed between active and inactive individuals, significant differences were found in sleep latency (p=0.02), daytime dysfunction (difficulties in performing daytime tasks due to poor sleep quality) (p=0.02), and the total PSQI (p=0.02). Binary logistic regression with crude analysis showed that inactive participants are 4.3 times more likely to have poor sleep quality when compared to active participants (odds ratio = 4.311; 95% confidence interval 1.338-13.888; p=0.014). Multinomial regression analysis showed that being physically active can be a protective factor.

Conclusions: There is a high prevalence of sleep disorders and insufficient practice of physical exercise among patients with fibromyalgia. It is suggested that regular physical exercise may be related to sleep quality, and more active participants have fewer sleep disorders, with exercise being a protective factor.