5 Ways Lack of Sleep Affects Brain Health and Mood

Lack Of Sleep

Sleep is still somewhat of a mystery, even to scientists. The brightest scientific minds don’t completely understand what happens when a person falls asleep. What is clear is that sleep is important for mental and physical health. Although sleep is vital for every organ in your body, the brain is most affected by a lack of sleep. Not getting enough sleep can make you feel more than just irritable and cranky; it alters brain function and health in some surprising ways. Let’s look at why sleep is so important for keeping your brain fit and functional.

Not Getting Enough Sleep Can Lead to Mood Disturbances

If you think you’re crankier after a night of poor sleep, it’s not your imagination. Studies show depriving your body of sleep can lead to symptoms like anxiety, depression, or mood swings, and even more serious symptoms like paranoia. When people go without sleep for a long period, it’s not uncommon for them to develop delusions or hallucinations where they sense things that aren’t there. It’s almost like these folks enter a dream state while still awake, so intent is the body on making up sleep loss. Lack of sleep can also worsen mental health disorders too. For example, psychiatrists say prolonged sleep deprivation can trigger manic or depressive episodes in people with bipolar disorder.

Your Brain Can’t “Clean Up” as Effectively

Sleep also helps your body “keep house.” During sleep, your brain goes into clean-up mode. You might think sleep is only a period of rest, but even as you slumber, your brain works hard to remove damaged proteins by disposing of them through a network of lymphatic channels called the g-lymphatics. Eliminating these damaged proteins may be important for brain health, as people with Alzheimer’s disease have higher levels of these misfolded proteins in their brain tissue. By getting quality sleep, you ensure your g-lymphatics can do their clean-up job and help your brain stay healthy. According to some studies, people who sleep less than 6 hours per night are at higher risk of neurodegenerative diseases like Alzheimer’s disease.

Skimping on Sleep Affects How Sensitive You Are to Pain

According to the Centers for Disease Control and Prevention (CDC), 20% of the population suffers from chronic pain in one form or other. Getting a good night’s sleep may help ease those pain symptoms. A study found that when people slept an additional 1.8 hours, they pulled their hand away from a hot flame slower than when they skimped on sleep. The conclusion was that getting more sleep may increase a person’s pain threshold and make them more pain tolerant. Another study found that patients with rheumatoid arthritis reported more pain and mood disturbances when they slept less.

Lack of Sleep Makes It Harder to Learn and Focus

It’s during sleep that your brain sends new information that you’ve acquired during the day into long-term memory storage. When you shortchange yourself on sleep, some of what you learned may never make it to its ultimate destination. Therefore, you’re less likely to remember what you learned. So, you don’t want to skimp on sleep the night before a big exam or any other occasion where your brain must be sharp.

Poor Sleep Can Make You Clumsier

If you find yourself stumbling around more or being more clumsy than usual, question your sleep habits. Lack of sleep can slow your reflexes and affect your motor skills and balance. It can also alter your depth perception, making it easier to fall. Plus, skimping on sleep can lead to more serious health issues. According to the American Academy of Sleep Medicine, 20% of motor vehicle accidents are because of driver fatigue. Just as you shouldn’t drink and drive, don’t sleep and drive either. It could be harmful to your health!

The Bottom Line

It’s not clear what the ideal amount of sleep is for optimal brain health, but most research suggests between 7 and 8 hours per night for the average adult, regardless of age. Contrary to popular belief, sleep requirements don’t go down with age. The elderly need almost as much sleep as younger adults, although they often have more problems staying asleep.

Sleep quality counts too. A night of fitful tossing and turning can be just as harmful as not sleeping at all. Here are some tips for optimizing the amount of sleep you get along with sleep quality:

  • Go to bed at the same time each night, preferably before 10:00 P.M.
  • Arise at the same time each morning, even on weekends.
  • Avoid using electronic devices within 2 hours of bedtime.
  • Keep the temperature of your sleeping area no higher than 65 degrees F.
  • Consider taking a warm bath before bedtime.
  • Some people benefit from melatonin for sleep but consult your health care provider before taking it.
  • Avoid eating sugar or ultra-processed carbohydrates within a few hours of bedtime.
  • Studies show exercising in the morning improves sleep quality.
  • Keep your bedroom as dark as possible or wear a sleeping mask to block light.
  • Avoid caffeine and alcohol.
  • Make sure you have a high-quality mattress that supports and feels comfortable.
  • Expose your eyes to natural light as early in the morning as possible.

If you have persistent sleep problems, check with your physician. Medical problems like sleep apnea can cause poor sleep and frequent nighttime awakenings.



  • Chen JC, Espeland MA, Brunner RL et al. (2016) Sleep duration, cognitive decline, and dementia risk in older women. Alzheimers Dement, 12, 21-33.
  • Centers for Disease Control and Prevention. “Prevalence of Chronic Pain and High-Impact Chronic Pain Among Adults — United States, 2016”
  • J Pain. 2013 Dec; 14(12): 1539-1552.doi: 10.1016/j.jpain.2013.08.007.
  • 2012 Apr 1; 35(4): 537-543.Published online 2012 Apr 1. doi: 10.5665/sleep.1742.
  • “Drowsy Driving Fact Sheet” American Academy of Sleep Medicine. 2 December 2009.
  • J. Psychiatry. 144 (2): 201-204. doi:10.1176/ajp.144.2.201.
  • com. “Napping before an exam is as good for your memory as cramming”
  • org. “Healthy Sleep Tips”



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