Pain and sleep
The New York Times reported on October 23, 2007, that a sleep researcher from the Johns Hopkins School of Medicine had conducted a new study that shed light on the relationship between pain and sleep. Michael Smith explained that three groups of healthy young students were subjected to variable amounts of sleep disturbance or deprivation. He found that "fragmented sleep" led to severe impairments the following day in pain pathways. The subjects "felt pain more easily, were less able to inhibit pain, and even developed spontanteous pain" such as mild backaches and headaches.
Timothy Roehrs, director of sleep disorders research at the Henry Ford Hospital corroborated these findings in a separate study of fragmented sleep, and also demonstrated that "getting more sleep...had the opposite effect." Study participants in the sub-group who stayed in bed a minimum of ten hours per day demonstrated reduced sensitivity to pain "to the same degree as [if they had taken] a tablet of codeine".