Sleep on It – the Connection Between Sleep and Memory.

What Happens When We Are Asleep

We all know how much better we feel after a good refreshing night’s sleep.  Sleep is the time when our brains and bodies carry out essential maintenance and repairs, undisturbed by physical activity and mental distractions.  Sleep is the time when our brains are believed to turn short term memories into long term ones, consolidate what we have experienced during the day and carry out various chemical processes that are literally the equivalent to taking out the garbage.  People who are sleep deprived may find it difficult to think clearly or concentrate. They may experience visual disturbances, light headedness and mild to severe confusion and a sense of disorientation.

Sleep and Studying

This is why the current advice to students is to get a good night’s sleep before an exam rather than trying to swot all night.  One learns more on the principal of little and often than by trying to cram a whole semester’s worth of work into a non-stop coffee and junk food fueled round the clock study binge with no little or no sleep.  Learn something new every day and give your brain a chance to consolidate the information before taking on the next task and you will perform much better – and remember much more – when the exams come around.

Sleep and Problem-Solving

A good night’s sleep also helps us with problem-solving.  While we are asleep our brains are not just busy consolidating memories but also making associations between new and existing knowledge, literally making sense of it all.  There is a lot of truth in the old saying, ‘sleep on your problems and a solution will come to you in the morning.’

Sleep and Alzheimer’s Disease

Researchers have long observed that there is a correlation between people who get by on very little sleep – only 4-5 hours a night – and an increased risk of developing Alzheimer’s disease.  The late British Prime Minister, Margaret Thatcher, is one celebrated example of someone who prided herself on never needing more than 4 hours sleep a night and who ultimately developed Alzheimer’s disease.  People who sleep poorly with 5 hours or less sleep per night show a marked increase in the build-up of beta-amyloid in the brain, one of the characteristics of Alzheimer’s disease. What is not clear at this stage is whether it is the beta-amyloid accumulation that causes the poor sleep or vice versa.  It could be that their minimal sleeping patterns are an early warning signal of Alzheimer’s disease, indicative of beta-amyloid build up long before other symptoms such as short term memory loss become obvious.  If this is the case, it may be possible to slow down or stop the progression of the disease at this early stage by remedying the sleep disruption or stopping the beta-amyloid accumulation. One of the greatest difficulties in finding remedies for Alzheimer’s disease is the incredibly complex array of possible causes and effects that scientists have to sift through in the course of their research.

Sleep and Your Body Clock

You may have heard of circadian rhythms.  This is a kind of body clock that governs our awareness of when to wake, when to sleep, when to eat and so on, dependent on the external factors of light and dark.  Circadian rhythms have been identified in most living things including plants and animals as well as humans.  This is what is disrupted when you have jet lag after flying over several time zones, as your brain is saying ‘bed time’ when it is still broad daylight at your destination.  This cycle is consciously disrupted if you do shift work as you have to train yourself to be awake at a time when your circadian clock wants you to sleep.  It has only been realised in recent decades that people who have worked night shifts most of their lives are at an increased risk of developing Alzheimer’s disease and other long term health issues.  Catching up on missed sleep during the day is not a substitute for good quality sleep at night with the lights out.  It is worth remembering that in terms of human evolution it has only been very recently, with the advent of affordable and reliable sources of light, that we have been able to stay up at night, not just for fun but also to work.  In the developing world many people still rise with the sun and go to bed when it gets dark, as nature intended us to do.

Alzheimer’s Disease and Sundowning

Sundowning is a symptom of Alzheimer’s disease where the patient becomes distressed and agitated at sunset, hence the name.  This is believed to be caused by a disruption to the circadian rhythms as the disease progresses, causing conflicting messages between what is perceived and how the failing brain interprets this information.  Many people with Alzheimer’s disease fall into a pattern of staying awake or sleeping fitfully at night and then napping during the day.  Research is being done to see if altering this back to a more normal pattern through the use of sleep aids and medication would reduce confusion and slow down the progression of the disease.  

Sleep and the Elderly

Sleep disturbances are common even among healthy elderly people.  Sleep apnea, a breathing disorder that causes the sufferer to wake up briefly dozens of times a night, can cause memory problems and day-time fatigue. This can often be remedied by a session at a sleep clinic to determine if this is the case and then the use either of a device to keep airways open at night or a minor surgical procedure to shorten the uvula at the back of the throat.  Prostate problems disrupt the sleep of many men.  Women may have bladder problems too that cause them to get up several times in the night.  Many of these causes can be remedied by a chat with the GP so there is no need to regard them as something one has to live with as one gets older.


Whatever the stage we are in our lives, the conclusion is that we all benefit from a good night’s sleep and that our brains are sharper and function better as a result.

4 thoughts on “Sleep on It – the Connection Between Sleep and Memory.

  1. PP HaridasEmbrandiri Das

    Dear doctor I have a problem .while I start to sleep I also start to watch bad dreams this problem affected at me 15 years still I have this problem. Because of this I can’t concentrate anything I am out of control .For this iam having a tablet daily ( venix XR 75) daily two times. Please tell me a solution for this .

  2. Cindy

    I am slow at talking sometimes. I have terrible word find. I was born with one half of my brain absent. I I just was told this recently by professionals. Right now my memory is poor. It scares me cause I don’t know if it is my Bipolar disorder or something else.

    1. adriana Post author

      Thank you for your comment. Unfortunately as we are not doctors we are unable to make a diagnosis or tell you if your memory problems are related to your bipolar disorder or something else. Please discuss your concerns with your physician as he will have your case history and notes.


Leave a Reply

Your email address will not be published. Required fields are marked *