648 Associations between objective afternoon and evening physical activity and polysomnographic sleep in fibromyalgia

Abstract

Abstract Introduction Patients with fibromyalgia (FM) suffer from pain which limits physical activity and disrupts sleep. Research examining the relationship between pre-bedtime physical activity, pain, and objective sleep is limited. This study examined whether objectively measured activity levels (via actigraphy), pain intensity, or their interaction are associated with polysomnographic sleep outcomes and sleep architecture. Methods Adults with FM (n=158, Mage=52, SD=12, 93% female) completed 14 daily pain ratings, 14 days of actigraphy, and a single night of polysomnography. Activity levels (i.e., magnitude of wrist motion captured per 30 second epoch) were recorded, and average afternoon/evening activity for intervals 12:00-15:00, 15:00-18:00, and 18:00-21:00 was computed, removing days in which participants slept during these periods. Sleep architecture was quantified as the percentage of sleep time in rapid eye movement (%rem) and non-rem (i.e. %stage 1, %stage 2, and %stage 3). Multiple regressions examined whether average afternoon/evening activity, average evening pain [0 (no pain)–100 (most intense pain imaginable)], or their interaction predicted polysomnographic sleep onset latency (SOL), wake after sleep onset (WASO), sleep efficiency (SE), %stage 1, %stage 2, %stage 3, and %rem, controlling for age, body mass index, average individual bedtime, time in bed, and sleep or pain medication usage. Results Greater afternoon activity from 12:00-15:00 was independently associated with lower SE (B= -.08, p=.01), greater WASO (B=.45, p<.001), and greater %stage 1 (B=.04, p<.01). Pain intensity interacted with physical activity from 12:00-15:00 such that the association between physical activity and higher WASO (p=.05) and greater %stage 1 (p<.01) was stronger for individuals with higher pain. Pain intensity and activity from 15:00-18:00, and 18:00-21:00 were not associated with sleep outcomes. Conclusion Our results suggest greater afternoon activity is associated with greater polysomnographic sleep fragmentation and greater %stage 1 sleep in FM, and these relationships are stronger for individuals with higher pain. These relationships are consistent with activity pacing recommendations for chronic pain and suggest pacing in the afternoon may be important for good sleep in FM. However, future research examining causal pathways linking physical activity levels and timing, pain, and sleep is needed. Support (if any) Support: NIAMS (R01AR055160/R01AR005160- S1;PI McCrae). Data collected at University of Florida (Clinical Trial-NCT02001077;PI McCrae).