Loss of sleep and learning

When I was a medical student, it was a common practice to cram and study up to 3 or 4 a.m. before an examination. We believed that by doing so, we would perform better in the test because we studied longer.

In the past two decades, sleep studies conducted in the laboratories of cognitive psychologists are showing the opposite. Students, as well as scientists, should have about eight hours of sleep before an examination for a better performance. Adding a nap in the afternoon will also improve memory.

In a study of soldiers operating complex military hardware, it was found that one night of sleep loss resulted in about 30-percent loss of cognitive skills and drop in performance. If soldiers are deprived of two nights of sleep, a 60-percent drop in performance is the outcome.

Lack of sleep may be one reason for the disaster involving the Challenger space shuttle in 1986. According to the National Sleep Foundation of the United States, the managers of the National Aeronautics and Space Administration may have made errors in judgment because they were awake for 20 hours before the blast-off.

In a study, a group of students were given a series of math problems with some tips on how to solve these. They were told of a shortcut solution to the problems that they should discover during the process. They were tested 12 hours after the training. Of the students who were not allowed to sleep before the math test, only 20 percent discovered the shortcut. However, those students who were allowed eight hours of sleep performed much better. Sixty percent of them found the shortcut.

Sleep loss also affects how we utilize the food we eat. When people are sleep-deprived, their ability to use the food they have eaten is reduced by about 30 percent, which also results in decreased insulin production and extraction of energy from glucose, a critical brain food. While this metabolic process is going on in the body, another chemical is accumulating and causing havoc: Cortisol is increased, resulting in a faster aging process.

If a healthy 30-year-old does not have sufficient sleep for six straight days, his body chemistry will display that of a 60-year-old. It will take him about a week to recover and get back to the blood metabolism of his younger years.

The more we study the effects of sleep loss, the more we will find that the purpose of adequate sleep is to achieve better memory and improved learning. Sleep loss means mind loss. It shackles learning in many ways. It curtails critical thinking, messes up memory and mood, retards reasoning, and shutters quantitative skills.

Reading the discoveries and innovations in the arts and sciences, we will find that many of them were the product of the expression “Let’s sleep on it.”

Take the story of the Russian scientist Dimitri Ivanovich Mendeleyev. And if we had enough sleep the night before the lecture on the Periodic Table of Elements, we will recall that Mendeleyev single-handedly and systematically organized the whole science of chemistry. One night while thinking about the nature of the universe while playing solitaire, he nodded off. When he awoke, he came up with how all of the atoms in the universe were organized and formulated the now universally used Periodic Table of Elements.

If our teachers are still giving lectures in the early afternoon, why? Science is telling us that much of the students’ mental alertness is down at this time. We have to change our educational processes to improve learning. If we continue with the current timing of lectures, we will be wasting the precious time of both teachers and students.

Because sleep improves learning, we should also promote naps. To take advantage of this idea, engineers at MetroNaps have created a nap-on-the-go device called a Sleep Pod. It is a portable, high-tech recliner that can fit in an office equipped with light-canceling visors, noise-reducing earphones, and heat coils that monitor the temperature of the pod. A cheaper version of this Sleep Pod can be devised for school use.

Meetings, conferences and presentations should not be held in the early afternoon when the brain is naturally prone to slumber. Some US companies engaged in the creative areas of advertising, marketing and research have allowed their employees to take a regular half-hour nap of their own choosing.

In the United States, a practical result of the studies on the effect of sleep loss is restricting the number of hours per day of long-distance truck drivers. They are mandated to take a rest after 11 hours of driving. Meanwhile, each flight crew member must have a minimum of eight hours of rest in any 24-hour period that includes flight time. Physicians in training, also known as medical residents, are governed by state laws prohibiting back-to-back night calls. Legislation now limits the work week of medical residents to 80 hours, and on-call duty shifts to no more than 24 hours.

Given the new cognitive research on the effect of sleep loss on human performance, schools and other institutions should change the ways and means to be productive and reduce error by allowing adequate sleep on the job or in school.

Leonardo Leonidas, MD, is a retired assistant clinical professor in pediatrics and recipient of the Distinguished Career Teaching Award (2009) at Tufts University School of Medicine in Boston in the United States. He is a 1968 graduate of the University of the Philippines College of Medicine and was named outstanding UPCM alumnus in 2010. He is the author of the e-book “How to Have a Happy, Smart Child” at Amazon.com. E-mail: [email protected]