Sleep deprivation can result in serious negative effects on performance, including impaired driving, lack of hand-eye coordination, decreased concentration, and diminshed physical performance.

Residents (physicians in their post-medical school training) are notorious for working long hours with limited time for sleeping. During a heavy call schedule, residents work about 90 hours per week, including frequent overnight shifts. Studies have shown that residents on a traditional heavy call schedule get little sleep, have problems with attention, are more likely to commit serious errors, and have increased rates of motor vehicle near-misses and crashes. This has led to legislation in several states capping the number of hours residents may work per week.

A new study in the September 7, 2005 issue of the Journal of the American Medical Association found that during the final week of a heavy call rotation, residents exhibited serious performance impairments, similar to the effects of drinking alcohol even moderately.

About the Study

This study included 34 residents (16 men and 18 women) from the Brown University Pediatrics residency program. The residents were each tested four times in two separate sessions—light rotations and heavy rotations.

The light rotation testing session occurred during the final week of a relatively quiet rotation, which averaged 44 working hours per week with no night calls. During the sessions, the residents underwent performance tests, which included a simulated driving test, and tests of attention and alertness. These tests were performed twice—before and after consuming enough alcohol to reach a blood alcohol concentration (BAC) of 0.05 grams per 100 milliliters of blood (approximately 3-4 drinks).

The heavy rotation testing session occurred during the final week of an intensive rotation, which averaged 90 working hours per week, including a mandatory overnight call every fourth or fifth night (34-36 consecutive hours of work). The researchers conducted the performance testing before and after the participants consumed non-alcoholic placebo beverages.

The Findings

For the 24 hours prior to each test, the participants on light rotations got about 7.5 hours of sleep, compared with the heavy rotation participants’ four hours.

The participants on heavy rotations who consumed no alcohol (placebo beverage) actually reported being less alert and sleepier than those on light rotation who consumed alcohol. Compared to participants on light rotations without alcohol, residents on heavy rotations and on light rotations with alcohol had 7% to 10% slower reaction times and committed 40% to 70% more errors.

In the driving test, the participants on heavy rotations or light rotations with alcohol were more likely to swerve into another lane or off the road, and residents on heavy rotations were 29% more likely to vary speed than those on light rotations with alcohol.

These results do have certain limitations. First, most of the participants accurately guessed whether they were being served alcohol or the placebo beverage, which may have affected the findings. Also, the study was relatively small and the participants were not randomized to light or heavy rotations. Those on heavy rotations may have wanted to demonstrate worse impairment, which may have affected the study’s results.

How Does This Affect You?

These findings suggest that heavy call rotations during medical school training have a detrimental effect on performance, similar to that of alcohol. The study did not, however, evaluate the effects of heavy call rotations on medical performance, so this study cannot say for sure whether heavy call rotations affect medical practice. Nevertheless, few patients would want be under the care of a physician who just had three or four drinks at a local bar.

Research revealing negative consequences of heavy residency rotations has resulted in legislation in several states capping the number of hours residents may work per week. In response, residency programs have been developing alternative call schedules designed to reduce sleep deprivation. More residency programs should consider redesigning work schedules and finding ways sleep-deprived residents can reduce the risk of committing medical errors or crashing their cars on the way home from a long shift.

Similar to other studies, these findings suggest that sleep deprivation may be comparable to alcohol intoxication when it comes to certain performance activities, such as driving. Some laws make it illegal for truck drivers to drive when they are sleep deprived, so it makes sense that physicians should find ways to avoid sleep deprivation when practicing medicine.