Grueling hours and frequent overnight work shifts may be as rough on new doctors as a few cocktails, researchers report.

The study appears in The Journal of the American Medical Association. So does an editorial arguing that doctors need to be able to work marathon hours.

Those articles were both written long before Hurricane Katrina struck, but that sort of extreme emergency -- in which many doctors worked nonstop -- may be one reason why new doctors are trained on hard-core work shifts.

Then again, no one wants to be cared for by a doctor who’s too sleepy to work well. That conflict is at the heart of the doctor debate.

Scarce Sleep

The small study included 34 pediatrics residents who were about 28 years old. They took driving simulation and reaction-time tests four times.

Tests were done after a 44-hour work week (“light call”) and after a 90-hour weekly work schedule with frequent overnight shifts (“heavy call”).

The tests were also done after a “happy hour” of sorts. After the light call schedule, some doctors were given a few alcoholic drinks while others received no drinks. Some of those on the heavy call schedule got nonalcoholic drinks, but they didn’t know the drinks lacked alcohol. The rest of the heavy call schedule got no drinks.

The last piece of the puzzle was sleep time. Doctors on the heavy call schedule got only three hours of sleep. Those on the lighter schedule got more than twice as much sleep (6.5 hours). They wore devices that checked sleep and activity around the clock.

Heavy Call, Alcohol

The key finding: Test performance was as bad after a heavy work schedule as it was after drinking alcohol on a shorter shift.

For instance, reaction times were 7 percent to 10 percent in light call with alcohol, heavy call, and heavy call with placebo. There was no difference between light call with alcohol and heavy call with placebo.

On the driving simulation tests, speed variability was 29 percent greater during heavy call with placebo than light call with alcohol. Speed variability was also 34 percent to 75 percent higher in light call with alcohol, heavy call with placebo, and heavy call when compared with light call.

Time to Limit Hours?

Medical skills weren’t directly tested. Still, the findings support limiting extreme hours for new doctors, write the researchers. They included J. Todd Arnedt, PhD, of the University of Michigan’s Sleep and Chronophysiology Lab.

“We need to continue to find simple, practical, and effective strategies that hospitals and senior doctors can take to reduce sleep deprivation among residents,” says Arnedt in a news release.

He also calls for studies of doctors from different specialties.

Different View

“This is, without a doubt, a notable finding,” write editorialist Drew Dawson, PhD, and colleagues.

But they don’t support doing away with long hours for new doctors.

“In some scenarios, limiting working hours may increase risk to patients and physicians,” writes Dawson, who works at the University of South Australia’s Centre for Sleep Research.

“For example, restricting working hours may lead to restricted access to health care practitioners through a reduction in the labor supply, insufficient clinical preparation for the ‘real world,’ increased sleep restriction in senior physicians, or increases in error rates due to work intensification. Each of these could result in higher overall risk,” write the editorialists.

By Miranda Hitti, reviewed by Brunilda Nazario, MD

SOURCES: Arnedt, J. The Journal of the American Medical Association, Sept. 7, 2005; vol 294: pp 1025-1033. Dawson, D. The Journal of the American Medical Association, Sept. 7, 2005; vol 294: pp 1104-1106. News release, JAMA/Archives. News release, University of Michigan.