By Richard Restak, M.D., George Washington University School of Medicine and Health Sciences

Edited by Kate Findley, The Great Courses Daily

It’s tempting to think that if we sacrifice an hour or two of sleep, we’ll accomplish more. As it turns out, though, sleep is essential when it comes to optimizing our brain’s performance, and by extension, our efficiency and productivity. Dr. Richard Restak explains why.

What Does Your Brain Do While You Sleep?

In our fast-paced culture we hate downtime, and therefore sleep and naps are discouraged. As a result, we are sleeping 45 minutes less than the previous generation. However, sleep is extremely valuable for the brain.

Sleep-impaired judgment and performance are as disabling as alcohol intoxication. “When I was in medical school, we were kept up for sometimes 36 hours at a time,” Dr. Restak said. “We couldn’t perform our best under those circumstances. In fact, the more a person can sleep, the better they perform.”

The brain doesn’t turn off during sleep. Just like the tomato which stores energy during the day due to photosynthesis and uses that stored energy at night for growth, the brain takes in information by day and stores it at night while changing the structure of synapses. 

Most of our dreams are about current concepts since these are the synapses that have been used recently. A Tetris experiment, for example, showed that dreams of falling shapes occurred for people who had been playing Tetris on a regular basis. 

During sleep, the brain plays the same patterns of activity involved in learning and memory during the day. The more you learn, the greater the need for sleep that night. 

Avoiding the Over-Practice Effect

Consolidation, which involves fixing memories that occur whether we’re awake or asleep, is needed for learning. Enhancement, or improving upon what you have learned, occurs during sleep: It’s what’s called an “off-line” effect. 

With many activities, continually pushing forward and not allowing yourself the necessary restoration that sleep provides can be counterproductive. For example, with tennis, after you’ve played a while, you get the “over-practice” effect: instead of getting better, you get worse. 

The over-practice effect is caused by fatigue of the relevant neurons and circuits. You can combat this by refreshing the circuits through sleep; that way, both consolidation and enhancement are improved. 

The initial consolidation of something new takes about six hours. Don’t take up a new activity within that same framework; sleep on what you’ve learned. 

This way, your brain circuits will be refreshed. Consolidation prevents the interference effect, which occurs when some memories interfere with your brain’s ability to record other memories of a similar nature. 

Insomnia’s Effect on the Brain

Unfortunately, insomnia, or difficulty falling or staying asleep, is a common problem. According to one 2015 study, sleep disorders impact approximately 50 million to 70 million U.S. adults. 

What’s going on in the insomniac’s brain? Positron Emission Tomography (PET) scans show activity in the arousal circuits; this prevents restorative sleep, leading to daytime difficulties in learning, memory, concentration, and mood. 

For example, sleep-deprived rats in a water maze take longer to find the platform than rats who sleep a healthy amount. Sleep fragmentation affects their hippocampus as stress hormones build up and affect circuits for new memories. Insomnia decreases efficiency and impairs performance.

Insomnia is also linked to depression. We used to think that people had sleep problems because they were depressed. However, depression may actually be caused by sleep problems instead.

Think back to your last sleepless night. Chances are, you weren’t lying there thinking about how wonderful the world was; you were worrying and fretful or having personal doomsday scenarios. 

You were not awake because of worry; you were worrying because you were awake. The still of night gives us time to contemplate things we don’t normally think about in the busyness of daily life. Plus, simply thinking about how much sleep you’re losing can trigger anxiety and depression.  

Therefore, you should take the necessary steps to resolve insomnia. First of all, follow methods of sleep hygiene—avoid stimulants, try to relax, don’t review the next day’s plans, put your phone away, and don’t exercise right before bed. 

Next, seek professional help to rule out treatable conditions such as obstructive sleep apnea. Finally, you may need a short course of sleeping pills that would likely work as long as they largely preserve normal sleep architecture. 

The Power of a Nap

Even if you struggle to get sufficient sleep, you can still catch up with a nap. A power nap is nearly as effective a skill memory enhancer as a good night’s sleep. 

Finger dexterity, for example, increases 16 percent after a nap. Naps improve one’s ability to learn facts, words, concepts, and creativity, according to the research of Dr. K. Anders Ericsson. 

Naps also increase off-line learning nearly as much as a whole night’s sleep. They increase “sleep spindles,” the brief bursts of electrical activity seen in regions of new memory formation. 

However, there’s a paradox involved in establishing a nap habit: You can’t force it. The more you try to force yourself to sleep, the more awake you will be. Additionally, naps must be short so as not to interfere with nighttime sleeping. 

“Let me tell you how I established my nap habit,” Dr. Restak said. “I would set aside 20 minutes in the afternoon just to relax. … I would have my office manager call me after 20 minutes. 

“I would lay there, and the first several weeks I didn’t fall asleep, but then after a while, the brain learned that this is the time to take this short nap. … Now I can do this in almost any time. You can do the same thing; just try it and don’t force it.”

Think of naps as an opportunity for memory consolidation and enhancement, a chance to refresh the brain circuits involved in learning and memory, and an easy way to power down and increase your creative powers.

This article was edited by Kate Findley, Writer for The Great Courses Daily.

Dr. Richard Restak is Clinical Professor of Neurology at The George Washington University School of Medicine and Health Sciences. He earned his M.D. from Georgetown University School of Medicine. Professor Restak also maintains an active private practice in neurology and neuropsychiatry in Washington, D.C.