University Times

In one of the first studies of its kind, sleep researchers at the Sleep and Chronobiology Center at Western Psychiatric Institute and Clinic (WPIC) have determined that the quality of sleep begins to deteriorate much earlier than previously thought. According to Julie Carrier, post-doctoral fellow in the School of Medicine, "Middle age is a turning point for sleep. Some sleep patterns have already changed significantly by the time an average adult reaches age 30. Though these changes may go unnoticed at first, they may over time become a problem," she said.

Carrier and her colleagues tracked sleep patterns in 110 healthy study volunteers 20 to 59 years of age and found that sleep changed dramatically between ages 30 and 50. With age, people go to bed earlier and get up earlier, sleep less, wake up more during the night, and have more light stages and fewer deep stages of sleep.

According to Carrier, many of these gradual changes are most likely tied to age-related changes in features of the biological clock, a system that regulates the sleeping/waking cycle, alertness and body temperature.

The biological clock regulates the timing of psychological and physiological functions so that they are in tune within the individual and the environment, in effect telling the body when it is time to sleep and when to be awake. The mechanism is so important that disruptions, such as across-time-zone travel or shift work, can cause sleep problems leading to poor performance and even a higher risk of accidents.

Carrier presented the findings of the study last month at the annual meeting of the Associated Professional Sleep Societies in New Orleans.

She also received the Young Investigator Award from the Sleep Research Society (SRS) at the meeting. The SRS award recognizes an outstanding research effort by a new investigator in the field of sleep research. Co-authors of the WPIC study are Timothy H. Monk, Daniel J. Buysse and David Kupfer.

"The published paper which led to Dr. Carrier's award is unique in addressing the sleep patterns of the middle-aged, rather than just comparing old and young, and also in showing that many of these sleep changes over the middle years of life can be explained by changes in the biological clock," said Monk, who is professor of psychiatry at the medical school.

"Middle-aged people are a significant segment of the population who need to be alert and productive, so good sleep in essential," Carrier said. "Now we are learning that, as we age, we become less able to work shifts or handle jet lag, a big problem for industrial workers or those who must travel frequently for their jobs. If we are able to find out what is causing the biological clock to change with age, we may be able to discover ways to overcome these changes and help get these people back on track," she said.