0223 Total Sleep Deprivation and Pain Perception during Cold Noxious Stimuli in Older Adults

Abstract

Introduction: Our laboratory has previously reported an augmented pain response to 24-hour total sleep deprivation (TSD) in young men and women. Because aging is associated with a greater prevalence of chronic pain and diminished sleep quality, we hypothesized TSD would increase pain perception to the cold pressor test (CPT) in older adults. Furthermore, we hypothesized this relationship would be stronger in postmenopausal women compared to age-matched men. Methods: Eighteen participants (9 women) between 55 and 75 years were tested once after 24-hour TSD and once after normal sleep (NS) using a randomized, cross-over design. Following a supine baseline, subjects performed a 2-min CPT by immersing their left hand in water (0-3°C). Perceived pain was recorded every 15 seconds during simultaneous recordings of muscle sympathetic nerve activity (MSNA; microneurography). Results: Age (61±2 vs. 60±1 years) and BMI (26±1 vs. 27±1 kg/ m2) were not different between women and men, respectively. CPT elicited a graded increase of perceived pain (time, p<0.001), and increases were significantly greater during TSD (condition, p<0.05). These responses were not different between men and women (time × condition × sex, p>0.05). The condition effect was also observed when pain was expressed as mean change from baseline (NS, Δ6.9 ± 2.4 vs. TSD, Δ8.2 ± 2.4 a.u.; p=0.041) and peak change from baseline (NS, Δ8.4 ± 2.7 vs. TSD, Δ9.7 ± 2.5 a.u.; p=0.039). Changes in pain were correlated with changes in MSNA during the initial 30 seconds of CPT during both NS (r=0.513; p =0.025) and TSD (r=0.528; p=0.020). Conclusion: TSD significantly augments perceived pain during cold noxious stimuli in older adults. Contrary to our initial hypothesis, this increased pain perception is not significantly different between men and women. Sympathetic reactivity during the initial phase of CPT was associated with changes in pain, but the clinical relevance of this relationship remains unclear. Our findings support the concept of sleep as a cost effective, therapeutic strategy for reducing pain in older men and women.