Purpose: Restoring sleep is associated with psychological well-being. In contrast, poor sleep leads to impaired daily cognitive, emotional, and social functioning. Both commonplace and expert opinion hold that exercise has a favorable impact on preventing poor sleep and improving its quality. However, the scientific basis for this opinion remains limited, and results are mixed. The aim of the present study, therefore, was to explore the impact of perceived physical fitness, exercise, and a perceived lack of activity on sleep in early adulthood. Gender-related patterns were also examined.
Methods: A total of 862 participants (639 females and 223 males; mean ± SD = 24.67 ± 5.91 yr) took part in the study. Respondents completed a series of self-report questionnaires assessing perceived physical fitness, exercise, perceived lack of physical activity, insomnia (Insomnia Severity Index), dysfunctional sleep-related thoughts (Fragebogen zur Erfassung allgemeiner Persönlichkeitsmerkmale Schlafgestörter), and quality of sleep (Pittsburgh Sleep Quality Index).
Results: High perceived physical fitness, but not exercise, was associated with favorable scores for various sleep indicators. A perceived lack of physical activity was associated with poor sleep. Perceived physical fitness and exercise were moderately correlated. Compared with males, females reported more sleep difficulties and also more dysfunctional sleep-related thoughts.
Conclusions: For early adulthood, findings did not support commonplace or expert opinion that exercise behavior has a favorable influence on sleep. Rather, the findings lend support to the importance of cognitive processes in the onset and maintenance of sleep complaints.