Abstract

Background: Over 30% of people with obstructive sleep apnea have co-morbid chronic insomnia. This combination (COMISA) worsens daytime functioning and health outcomes more than either condition alone. Its effects on physical activity (PA) are unknown. This study’s aims were to i) compare objectively-measured PA levels and diurnal patterns between people with COMISA and age- and sex-matched Insomniacs (INS) and Good Sleepers (GS); and ii) assess the impact of an 8-week exercise (Ex) or relaxation (Rel) intervention on PA in COMISA.
Methods: This secondary analysis used activity data collected from 15 COMISA participants, 15 INS, and 15 GS matched on age (±5 years) and sex. Participants wore an accelerometer (Actiwatch-2) on their non-dominant wrist and recorded sleep/wake activities in a diary for 14 days. Mean daily PA levels and morning/afternoon/evening PA levels were compared between groups with a repeated-measures ANOVA, as were pre- to post-intervention changes in PA levels in COMISA participants randomly assigned to Ex (N=4) or Rel (N=4).
Results: Mean daily PA was 278±40, 316±108, and 335±121 counts/minute (cpm) in COMISA, INS, and GS respectively. The group difference was not significant, but the effect size was moderate (η_p^( 2)=0.063). Evening PA level was significantly lower than morning or afternoon level across groups (p<0.001). Mean PA level did not change after Ex or Rel.
Conclusion: These findings confirm the presence of an evening drop in PA level across populations, signal a moderate negative effect of COMISA on PA levels, and call for interventions specifically targeting PA behavior in this population.