get your sleep

The new frontier of what to expect, and what to do about it, involves studies of the relationship of sleep to pain. It’s no surprise that pain can disrupt sleep. But what is new is that a lack of sleep can apparently increase the sensation of pain.

Michael T. Smith, the research and training director of the behavioral sleep medicine program at Johns Hopkins School of Medicine, reached that conclusion with a study of healthy young people. One group slept normally for eight hours in the hospital. Another was awakened every hour by a nurse and kept up for 20 minutes. Their sleep pattern was meant to mimic the fragmented sleep of elderly people. A third group was allowed four hours of solid sleep.

Comparing the second and third groups allowed Dr. Smith to tease apart the causes of the problems that arise from fragmented sleep: were they because of the short total sleep time, or because of the disrupted nature of the sleep?

Fragmented sleep, he found, led to severe impairments the next day in pain pathways. The subjects felt pain more easily, were less able to inhibit pain, and even developed spontaneous pain, like mild backaches and headaches.

Timothy Roehrs, director of the sleep disorders research center at Henry Ford Hospital in Detroit, also found that healthy young people became exquisitely sensitive to pain after a night of fragmented sleep.

And getting more sleep, Dr. Roehrs found, had the opposite effect. His subjects were young healthy people who said they were chronically sleepy, just not getting enough time to sleep at night. Dr. Roehrs had them stay in bed 10 hours a night. The extra sleep, he said, reduced their sensitivity to pain to the same degree as a tablet of codeine.

-NY Times (also see this piece on learning and memory)