Exercise to improve sleep in insomnia: exploration of the bidirectional effects.
Level 4 - case-series / case-control
Single-arm prospective study with no control group.
PubMed 23946713 · doi:10.5664/jcsm.2930
What was done
Eleven women (mean age 61.27 +/- 4.15 years) with insomnia engaged in 30 minutes of aerobic exercise three times per week over 16 weeks. Self-reported sleep quality was assessed at baseline and 16 weeks. Daily sleep and exercise logs and continuous wrist actigraphy tracked sleep onset latency, total sleep time, sleep efficiency, wake after sleep onset, and fragmentation index. Daily bidirectional associations between sleep variables and exercise, as well as baseline moderators (age, fitness, baseline sleep metrics), were evaluated.
What was found
Total sleep time, sleep efficiency, and global self-reported sleep quality improved from baseline to 16 weeks (all p < 0.05; exact numerical values not reported). Baseline daytime sleepiness negatively correlated with exercise session duration (p < 0.05). On a day-to-day level, exercise was not associated with subjective or objective sleep variables the following night. However, longer sleep onset latency was followed by shorter exercise duration the next day (p < 0.05). Baseline total sleep time moderated the relationship between daily sleep time and next-day exercise duration (p < 0.05), with shorter sleep predicting shorter next-day exercise more strongly in those with shorter baseline sleep.
Why it matters
This study suggests that in individuals with insomnia, acute day-to-day interactions may be driven by sleep quality influencing subsequent physical activity rather than same-day exercise directly improving sleep.
Limits
The sample size was very small (n = 11) and limited strictly to older women. There was no non-exercise control group, and the abstract does not report point estimates, confidence intervals, or exact effect sizes.
Cited by
- partial A clinical trial in sedentary women with insomnia found that acute exercise did not improve sleep and actually exacerbated sleep problems, whereas several months of continuous exercise produced significant sleep improvements.