The abilities of pain to interfere with sleep and sleep quality to affect pain sensitivity create a reciprocal relationship between sleep and pain. In some cases, pain can be lessened by improving sleep quality or encouraging more activity. Similarly, pain and activity have a complex relationship in which pain can decrease activity, and activity can decrease or exacerbate pain, depending upon the level of activity, structural abnormalities, and types of pain. The intimate and complex relationships among pain, sleep, and activity suggest that studies of pain and pain therapies should include valid measures of sleep and daytime activity so that these dimensions of pain can be quantified and their effects on pain better understood.
This paper summarizes some of the documented relationships among pain, sleep and activity to help provide a rational basis for the design of clinical pain trials. The inclusion of quantitative (and when possible, objective) measures of sleep and activity can more fully characterize the pain experience being studied6.