In television medical shows, doctors are always wide awake, alert and able to respond to emergencies instantly. In reality, according to the authors of a study published in a recent issue of Critical Care Medicine, doctors are often sleep-deprived -- a state that is adversely affecting them in terms of alertness, well-being and thinking skills.

The study was conducted as a result of physicians' complaints of the 24-hour shifts at the emergency department (ED). According to the study, working long hours, especially night shifts, causes a disruption of biological rhythms and a disturbance in social and family life. Additionally, study participants felt that work hours should be limited because it can affect their health and others' safety.

"It can be regarded as common knowledge that prolonged periods of wakefulness and irregular rest-activity lead to reduced well-being, increasing levels of sleepiness on the job and worrying decreases in performance," said Richard Frey, M.D., University of Vienna, Department of Psychiatry, co-author of the study.

A sample of 11 physicians, four females and seven males -- ranging from 28 to 43 years of age who had been working in the Emergency Department between four and 50 months -- participated in the study. Most of the participants were relatively young with an average work experience of 31 months in the ED.

They were tested twice during two regular 24-hour shifts, in the morning around 8 a.m., and then again at midnight. During the tests, an electroencephalography, or EEG, was performed to check brain activation, as well as psychometric tests to check mental alertness.

The statuses to categorize the participant's condition were 1) no-rest condition (no daytime rest), which is their usual routine, and 2) rest condition (instructed to take a four-hour rest, which could be used to sleep).

In the rest and no-rest condition, the EEG test found their alpha power, associated with alertness was significantly reduced. This means that the participants showed less alertness during both rest and no-rest conditions.

Also, the nighttime delta activity, which measures drowsiness, showed the participants were significantly less drowsy when they had rest then when they were without rest. Thus, tiredness increased more during night duties on days without rest than with rest. On days with rest, deterioration was only seen in subjects who did not nap.

The study provides objective evidence regarding the effects of sleep deprivation on physician performance and the data shows that a short period of sleep (nap) will reverse some of the tiredness and drowsiness associated with lack of sleep.

The authors argue for more direct studies in this important field to allow decisions about work shifts to be decided using research data.

SOURCE: Critical Care Medicine, October 2002.