Young african american woman sleeping in bed at night.

Sleep and mental wellbeing

Last update: 05.02.2023

Reading time: 6 min

Sleep is when your brain processes and stores information from the day, repairs, resets, and prepares itself—and you—for the next day. Your mental health and wellbeing is affected by the intricate interactions between the different parts of the brain that happen while you sleep. However, data show that sleep loss is becoming more prevalent than ever, with over 1 in 3 Americans not getting enough sleep on a regular basis.¹ Not getting enough quality sleep causes a ripple effect throughout the brain and body that may impact your mental health.

Keep reading to learn how sleep affects your mental wellbeing.

How sleep affects your mental wellbeing

Sleep supports healthy brain function
Sleep aids the learning process
Sleep helps with emotional balance
Sleep supports a healthy emotional state and decision-making abilities.
Sleep supports hormonal balance.
A good night’s sleep gives your brain time to consolidate and organize memories
Sleep gets rid of the energy waste your brain doesn’t need
Sleep deprivation affects motivation, focus and productivity
Lack of sleep makes it easier to doze off

1. Sleep supports healthy brain function
While you sleep, your busy brain cells finally get some time for self-care. Every night they restore their internal balance, or homeostasis, and strengthen their connections (synapses), with other brain cells. This process, which happens during slow wave sleep phases, improves neuroplasticity—the brain’s ability to coordinate efficient communication within and between brain areas, so it can be resilient and adapt to change.²
2. Sleep aids the learning process
While you sleep, your brain takes new information it’s received throughout the day and stores it in the appropriate areas. This means that tomorrow, next week and a year down the road, you’ll be able to use the skills you learned today at school or on the job. The process of creating long-term storage so that new information and skills become permanent happens during the sleep phase in which the brain waves are at their slowest.³ This wave pattern, known as delta waves, occurs during deep, non-dreaming sleep.
3. Sleep helps with emotional balance
While your brain is processing and storing the day’s events, it is also processing their emotional significance. This happens primarily during REM sleep and involves coordination between the primitive emotional center of the brain called the amygdala and the outer cortex.⁴
4. Sleep supports a healthy emotional state and decision-making abilities.
Getting enough sleep each night is essential for the brain to work optimally and process energy in a way that supports you best. With the help of an advanced imaging technique called positron emission tomography (or a PET scan), we can see how the brain alters its use of energy when you don’t get enough sleep. In research studies, PET studies have shown hyperactivity in the brain’s arousal and emotional centers and suppressed activity in the executive, decision-making areas in individuals with impaired sleep.⁵
5. Sleep supports hormonal balance.
When you don’t sleep enough, your brain doesn’t have enough time to maintain healthy and balanced hormone levels. Your body is forced to compensate and use hormones in a way that isn’t efficient in supporting your overall health and wellbeing. There are several ways sleep affects hormone balance:
- Sleep supports healthy testosterone levels.Your central nervous system and endocrine system are so closely interconnected that the two are often referred to as a singular neuroendocrine system. One of the ways sleep deprivation impacts endocrine function is by lowering levels of testosterone in both men and women. In the brain, testosterone enhances the activity of GABA (the “relaxing hormone”) and serotonin (the “happy hormone”), the two most important brain-calming neurotransmitters.⁶
- Sleep helps maintain production of brain-activating hormones.When you get too few hours of sleep, your brain stays active and alert. This requires increased production of brain-activating hormones, like norepinephrine and cortisol, which mobilize blood sugar to keep your brain and body going in the short term.⁷
- Sleep helps regulate the stress response system.When you don’t get enough sleep, your levels of the brain-activating hormones norepinephrine and cortisol stay elevated to keep your brain awake. Normally, cortisol is present at higher levels in the morning, which helps you to get out of bed and start your day, peaking around midday, and then declining to its lowest level during sleep. However, after a night of poor sleep, your brain requires more of these hormones to stay alert and functioning during the day, which keeps it in a more excited and excitable state. That’s why after a night of poor sleep, you may find it more difficult to stay focused. ⁴ ⁷
6. A good night’s sleep gives your brain time to consolidate and organize memories
When you learn something new during the day, that information is placed in temporary storage, somewhat like a blurry image. Then when you go to sleep, your brain can process and sort through the information. Part of the process of making memories permanent requires streamlining, or “pruning” the temporary synaptic connections that make up the blurry image into an efficient pathway within the brain. When you’re not sleeping enough, you have less ability to consolidate memory in this way.¹⁰
A good night’s sleep also helps you to respond quickly and accurately in day-to-day situations. During the decision-making process, your brain quickly accesses stored memories and then makes a best-guess choice between all of its options based on the information it’s gathered. The time it takes to access these memories, gather enough information, and arrive at a decision is known as “drift-rate.” Sleep deprivation affects drift rate, resulting in both longer decision-making times and errors in arriving at the correct choice.⁸ When it takes you longer to sort through memories and learnings, it can affect your workflow, making it harder to focus and work efficiently and productively.
7. Sleep gets rid of the energy waste your brain doesn’t need
Your brain uses more energy than any other organ in your body—even at rest. (9) Cells that consume a lot of energy produce a lot of metabolic waste. Sleep can get rid of some of those cellular waste products, called free radicals. Lack of sleep decreases the amount of time your brain has for internal housekeeping. As a result, free radicals build up, which can affect nerve function and memory storage.²
8. Sleep deprivation affects motivation, focus and productivity
A bad night’s sleep leaves you feeling tired and less alert the next day. Just thinking may seem like hard work, and the longer you have to stay focused on a task the greater performance is affected.¹¹ In one study, sleep-deprived participants consistently chose less challenging tasks than a well-rested control group.¹² Part of the reason for the lack of motivation is that sleep deprivation activates areas of the brain that seek a sense of reward and reduces activity in a brain area called the insula, that helps facilitate high-level attention and decision-making.¹¹ ¹² As a result, your brain seeks a greater reward while at the same time is less able to perform well.
9. Lack of sleep makes it easier to doze off
Do you ever jolt awake, before you even realize you fell asleep? If you’re really exhausted, like near the end of work after a night of poor sleep, and you find yourself nodding off or staring into space, this is called “microsleep.” These brief periods only last a few seconds, but they are involuntary and can interrupt your focus. Other signs of microsleep include inability to keep your eyes open and very small pupil diameter. Microsleep can decrease work productivity for some workers and lead to compromised ability to stay alert for those in labor-intensive professions.¹¹ ¹²

As you can see, sleep is so important in your overall health. Your brain uses an incredible amount of energy all day, every day. Make sure you’re thanking your brain by giving it what it really needs—a good night’s sleep, every night.

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