Have you ever wondered what effect lack of sleep has on you? At some point or most probably, all throughout your medical school career, you probably pull an all-nighter, staying up 24 hours straight, cramming for the next day's must-pass examination. Is that extra studying worth the effort? Or are you likely to lose as much as you gain by being exhausted on the day of the test?

The effect of sleep deprivation on your test-taking ability depends on the type of examination questions. If they are multiple choice or true-false questions, a night without sleep won't affect your ability to deal with them. The reason is that in answering such questions you rely on familiar, established problem-solving techniques, an ability unaffected by the loss of one night's sleep. But then, how familiar are you with USMLE questions? Does the question bank generated sets of questions for your practice tests in your USMLE review the same way the actual USMLE board questions are stated? You can never be sure as the questions contained therein are also subjected to development and improvement by a duly responsible organization.

The basic function of sleep is to repair the cerebral cortex from the wear and tear of conscious activity. The loss of creative ability is a signal that lack of sleep causes something to go wrong in the cerebral function, thereby disturbing some fundamental in the decision-making process. Most of the questions in the USMLE require you to decide – medical diagnosis, diagnostic tests, analysis of results, treatment. In order to answer such questions, you need to think flexibly, and this ability is diminished after only a single sleepless night. How can you decide properly and correctly with lack of sleep? Sleep deprivation may hinder your ability in high-risk situations like operating on a patient, emergency room stat surgical procedures as well simply prescribing a drug for your patient.

Accidents have been caused by lack of sleep such as what happened in the Three Mile Island power station. The control room operators were working on a slow shift rotation – days for a week, evenings for a week, then late nights for a week. Such cycle does not give enough time for the cerebral cortex to recover. The slow rotation shift may result in the worst possible human performance because it disrupts the body's biological clock – especially the sleep cycle.

Indeed, adequate sleep is a need that everybody recognizes such that New York State now requires hospital staff and personnel to work no longer than an average of 80 hours a week per month. "We think most patients would rather have a well-rested doctor than a zombie working on one-hour's sleep." - NY State Health Department (Sleep; the New York Times, 1989)