Sleep Fragmentation Hypersensitizes Healthy Young Women to Deep and Superficial Experimental Pain

Abstract The effect of sleep deprivation on pain sensitivity has typically been studied using total and partial sleep deprivation protocols. These protocols do not mimic the fragmented pattern of sleep disruption usually observed in individuals with clinical pain conditions. Therefore, we conducted a controlled-experiment to investigate the effect of sleep fragmentation on pain perception (deep pain: forearm muscle ischaemia, and superficial pain: graded pin-pricks applied to the skin) in 11 healthy young women following two consecutive nights of sleep fragmentation, compared with a normal night of sleep. Compared to normal sleep, sleep fragmentation resulted in significantly poorer sleep quality, morning vigilance, and global mood. Pin-prick threshold decreased significantly (increased sensitivity), as did habituation to ischaemic muscle pain (increased sensitivity), over the course of the two nights of sleep fragmentation compared to the night of normal sleep. Sleep fragmentation did not increase the maximum pain intensity reported during muscle ischaemia (no increase in gain), and nor did it increase the number of spontaneous pains reported by participants. Our data show that sleep fragmentation in healthy, young, pain-free women increases pain sensitivity in superficial and deep tissues, indicating a role for sleep disruption, through sleep fragmentation, in modulating pain perception.