We’ve all had that experience where we don’t get enough sleep and notice our brain feels extra foggy the next day. Maybe we’re slower to remember where we put our phone or keys, and we might not easily recall what day of the week it is or what’s on the day’s to-do list.
But while it’s clear that sleep deprivation can cause us to be more forgetful than usual, can a better night’s sleep actually boost our memory? Likewise, what happens when we are chronically sleep deprived—will that impact our memory on a more long-term basis?
We connected with sleep experts to help us unpack everything to know about sleep and memory, including the best ways to ensure you get enough sleep to keep your memory sharp.
Sleep and Your Memory
Sleep and memory are closely linked, and sleep plays a pivotal role in the formation and consolidation of our memories, says Sanam Hafeez, PsyD, neuropsychologist and director of Comprehend the Mind.
While we sleep, we cycle through different stages of sleep. Essentially, there are four main stages of sleep:
According to Dr. Hafeez, it’s mostly during SWS and REM sleep that the brain integrates information accumulated during your waking hours, and transfers these into your long-term memory stores. “This consolidation process strengthens neural connections linked to memories, enhancing the ability to learn and remember new information,” she says.
Each of these primary memory stages—SWS and REM—play slightly different roles. In a nutshell, SWS is for consolidating memories that include facts or events, Dr. Hafeez says. But REM sleep is more about procedural memory consolidation.
“During SWS, memories are transferred from short-term storage to long-term storage, making them more stable and easier to retrieve later on,” Dr. Hafeez describes. “REM sleep, characterized by dreaming, helps integrate new information into existing knowledge networks and strengthens procedural memories, such as skills and tasks.”
REM sleep, characterized by dreaming, helps integrate new information into existing knowledge networks and strengthens procedural memories, such as skills and tasks.
Sleep also helps protect memories by stabilizing and safeguarding them over time, Dr. Hafeez explains. This is due to something called synaptic plasticity. “Synaptic plasticity, essential for learning and memory, is supported during sleep, allowing the brain to reorganize and strengthen neural connections,” says Dr. Hafeez.
Sleep and memory in general are closely tied together, but sleep impacts many crucial cognitive processes, including learning and problem-solving, says Bijoy John, MD, board-certified sleep physician and founder and medical director at Sleep Fix Academy.
“Sufficient sleep allows our brains to process and store information effectively, facilitating optimal cognitive development,” he describes. “Even though the millions of neurons in the brain slow down during sleep, they’re still performing important work.” Dr. John adds that memory processing in particular is one of the most important benefits of a good night’s sleep.
Can Better Sleep Improve Your Memory?
It’s not just in your imagination: poor sleep makes our memory worse, and good sleep definitely improves it.
“Better sleep plays a significant role in improving memory,” Dr. Hafeez explains. “When we sleep well, especially during the crucial stages of deep slow-wave sleep (SWS) and REM (rapid eye movement) sleep, our brains undergo processes that are essential for memory formation and consolidation.”
As Dr. Hafeez notes, people who get enough sleep after learning new information tend to perform better on memory tests. For example, a meta-analytic review from 2021 looked at studies on people who were in the process of learning new information. The people who slept poorly after learning the new information performed poorly on performance tests the next day compared to people who slept sufficiently.
Dr. John suggests jogging your memory back to when you were in school. Imagine listening to a lecture during the day. While you may pay close attention to that lecture as it’s happening, it’s only after getting a good night’s sleep that night that you can lock in the information you learned.
“It’s as if the facts you heard at the lecture are in a pile on the floor, waiting to be appropriately organized into the right filing cabinet,” Dr. John describes. “When you sleep, your brain decides where each memory should be stored and places it in the correct spot so that you can access it the next time you are awake.” On the other hand, if you get a poor night’s sleep after the lecture, the info you learned may be forgotten altogether, he says.
What Poor Sleep Does to Your Brain
Sleep gives us a chance to recharge and to consolidate memories and newly learned information into longer-term memories. But there is another role that sleep plays in terms of brain health: sleep helps clear out some of the “gunk” that builds up in our brain during the day, Dr. John explains.
There is something called the glymphatic system which helps remove toxins that accumulate in the morning during our waking hours. “Every cell of our body produces waste that needs to be cleared to preserve cell function,” says Dr. Johns. The brain’s glymphatic system’s function is “akin to clearing the cobwebs, or cellular trash,” he describes. In other words, during sleep, our brain is refreshed for the next day, and we experience greater clarity.
Besides the daily clean-up and memory storage functions, poor sleep can actually have negative long-term impacts on our brain health and memories, says Chris Allen, MD, a board-certified sleep medicine physician, pediatric neurologist, and sleep science advisor at Aeroflow Sleep.
“Chronic sleep deprivation is associated with a decline in overall cognitive function, including attention, decision-making, problem-solving, and emotional regulation,” Dr. Allen says. “Over time, this can contribute to long-term cognitive issues and an increased risk of dementia.”
Chronic sleep deprivation is associated with a decline in overall cognitive function, including attention, decision-making, problem-solving, and emotional regulation.
Indeed, research has linked poor sleep over long periods of time with an increased risk of neurodegenerative diseases associated with aging. “Chronic sleep deprivation or poor sleep quality may accelerate cognitive decline and heighten the risk of conditions like Alzheimer’s disease,” Dr. Hafeez says.
But it’s not all gloom and doom. The reverse is true as well: maintaining healthy sleep habits throughout your life can support brain health and foster synaptic plasticity, or the brain’s ability to form new neural connections. “This ongoing neural adaptability is essential for continuous learning and adapting to cognitive challenges in older age,” says Dr. Hafeez.
8 Habits That Can Help Your Sleep and Memory
Sleep and memory go hand in hand, and the daily habits you engage in can have a strong impact on both your sleep and your memory. Dr. Allen shared his top tips for cultivating optimal sleep and memory:
- Stick to a regular sleep schedule, meaning that you go to bed and wake up at roughly the same time each day
- Eat well, focusing on a diet with plenty of fruits, veggies, lean proteins, and whole grains
- Try not to eat or drink alcohol in the hours close to bedtime
- Make a point of engaging in physical activity daily, but don’t engage in heavy exercise near bedtime
- Limit your ingestion of stimulants like caffeine and nicotine, especially later in the day and evening
- Add relaxation techniques into your daily routine, such as deep breathing, yoga, or mindfulness meditation
- Create a sleep-inducing environment, which means a cool, quiet, dark room, and comfortable bedding
- Limit screen time before bed
How much sleep do you need each night to optimize memory? It varies from one person to another, but most adults need seven to nine hours of sleep nightly, Dr. Allen says. “Consistently getting less than this amount can impair cognitive function,” he says. But it’s not just quantity—it’s also quality of sleep.
“Quality is as important as quantity,” says Dr. Allen. “Aim for uninterrupted sleep cycles to allow the brain to go through all the sleep stages, including deep NREM and REM sleep.”
It’s also important to address any potential sleep disorders which may be contributing to poor quality sleep says, Kevin Postol, DDS, president of the American Academy of Dental Sleep Medicine.
“Some people may struggle with getting proper rest due to a sleep disorder, such as sleep apnea or snoring,” Dr. Postol explains. “Left untreated, sleep disturbances can affect memory and even lead to larger health consequences.”
Dr. Postol notes that there are several safe, effective and comfortable ways to manage and treat conditions like sleep apnea and snoring, including oral appliance therapy. You should speak to your healthcare provider if you are concerned about a possible sleep disorder.
Bottom Line
We all know that not getting enough sleep makes us feel crappy, but it goes beyond that. Sleep plays an important role in memory. It helps consolidate and organize our memories and helps us retain recently learned information. There’s some evidence, too, that getting enough sleep throughout our lives can impact our memory as we get older.
The problem is that it can be super hard to get the sleep we need. But understanding the link between sleep memory might be just the motivation you need to prioritize sleep in your life and focus on good sleep hygiene, such as going to sleep at the same time each night, turning off screens before bed, and making sure to eat well and exercise during the day.
Know, too, that if you are having trouble getting enough sleep despite your best efforts, help is out here to help you get your ZZZs. Consider connecting with a healthcare provider if sleep continues to feel out of reach.