How Lack of Sleep Affects Brain Function

This article is an excerpt from the Shortform book guide to "Keep Sharp" by Sanjay Gupta. Shortform has the world's best summaries and analyses of books you should be reading.

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How does lack of sleep affect the brain? Can sleep deprivation impair cognitive functioning?

Our brains perform billions of molecular tasks while we sleep. Because of this, sleep keeps us sharp, creative, and able to process information. Inadequate or poor quality sleep not only makes us slow and tired, but it can also speed up age-related cognitive decline.

Keep reading to learn about the dangers of lack of sleep and its effects on brain function.

Problems Associated With Sleep Deprivation

Chronic inadequate sleep leads to a higher risk of many health issues, including dementia and cognitive decline. Extensive research on the effects of lack of sleep on brain functioning shows that sleep is more than just the brain’s chance to relax: It’s a vital phase of neural activity and regeneration.

Gupta goes over several studies that exhibit the different effects sleep deprivation has on the body. They are all related to each other, and they all can lead to brain impairment. 

  • A study showed that people who sleep less than six hours a night after a major coronary event were 29% more likely to suffer a second one.

(Shortform note: A recent study found that too little and too much sleep can increase your risk for a heart attack or stroke. People who slept less than six hours or more than seven hours a night were more likely to die from a heart attack or stroke.)

  • Another study revealed that sleeping less than six hours a night increases the chance of prediabetes developing into diabetes by 44%. Less than five hours of sleep and this number goes up to 68%.

(Shortforn note: Why does this happen? Sleep can affect blood sugar for several reasons. Even one night of sleep deprivation can lead to increased insulin resistance, the main factor behind Type 2 diabetes.)

  • One study found that just one night of inadequate sleep is enough to activate the inflammation process in the body. For unknown reasons, this is especially true for women.

(Shortform note: One study found that poor sleep increased inflammatory biomarkers in women 2.5 times more than in men. A possible explanation is that testosterone somehow helps to limit the inflammatory effects of sleep deprivation.)

Tips for Better Sleep

Gupta provides some easy-to-follow advice on getting more consistent rest:

Stay on schedule: Irregular sleep patterns are harmful to your health. Try to get up and go to sleep at roughly the same time every day. It can also help to establish bedtime rituals in which you take time to unwind and do something you find relaxing.

Pay attention to diet: What you eat and drink can affect your sleep. Caffeine after 2 p.m. can make it harder to fall asleep. Too much water before bed can cause you to wake up in the night to use the bathroom. Late meals and alcohol use can also disturb normal sleep cycles.

Keep your room dark at bedtime: Most forms of light, including sunlight and artificial light from lightbulbs or electronic devices, contain blue wavelengths. These wavelengths suppress melatonin, the hormone that makes you sleepy, and stimulate other areas of the brain that keep you alert. 

Sleeping Pills: Why to Avoid Them

Why We Sleep echoes Gupta’s advice in many ways. Walker also recommends maintaining a sleep schedule, reducing light, and eating a healthy diet. One thing Walker adds to the discussion is the use of sleeping pills. Sleeping pills are bad for you for several reasons:

Most sleeping pills are sedatives that affect the quality of sleep. Although you might get seven or eight hours of sleep when taking sleeping pills, you won’t get enough deep, restorative sleep. Sleeping pills lead to a brutal cycle. Sleeping pills may cause drowsiness in the daytime, which leads to more caffeine use or long naps, which makes it harder to fall asleep at night, which makes you more dependent on the sleeping pills. As you use the sleeping pills more and more, you build up a tolerance, making them both less effective and harder to quit.

There is a correlation between sleeping pill use and mortality. People who take sleeping pills are more likely to get in a car accident, get cancer, and have a weaker immune system.
How Lack of Sleep Affects Brain Function

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  • The steps you can take to prevent cognitive decline such as Alzheimer’s
  • How to keep your brain strong and resilient throughout your life
  • Foods to eat and avoid to maintain brain health

Darya Sinusoid

Darya’s love for reading started with fantasy novels (The LOTR trilogy is still her all-time-favorite). Growing up, however, she found herself transitioning to non-fiction, psychological, and self-help books. She has a degree in Psychology and a deep passion for the subject. She likes reading research-informed books that distill the workings of the human brain/mind/consciousness and thinking of ways to apply the insights to her own life. Some of her favorites include Thinking, Fast and Slow, How We Decide, and The Wisdom of the Enneagram.

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