We are sleep researchers, Bill and Wei, looking at why we sleep, what happens in our brains when we sleep (and when we don’t!). Specifically, we’re investigating potential links to stress and Alzheimer’s disease. Ask us anything!

What's the best way to wake up in the morning (e.g. in time for work) without a horrible battle against alarm clocks and snooze buttons? Being lurched out of deep sleep by your alarm clock can set you off kilter all day, yet most of us have to be up at a specific time every day. It seems like it's impossible to win?

Bill and Wei here: Thank you for the interesting question. We have a lot of sympathy! I would say if you struggle to get up every morning, one possibility is that you have not got enough sleep in general. My suggestion would be to identify if you are an owl (people who go to bed late and want to wake up late) or a lark (those who go to bed earlier and get up earlier). It sounds like you’re an owl - you naturally need to wake up later and go to be later. Ideally, it would be best if employers recognised the different “chronotypes’ of people and allowed them to start with their optimal circadian time. For example, Prof. Russell Foster at Oxford University has been advocating delayed school times because young people are particularly late risers.

I’ve pulled all nighters and stayed up for 24+ hours straight, while I feel negative physical side effects I also feel an odd sense of mental clarity and lucidity. Why do I almost feel sharper when sleep deprived?

Bill here - This is probably related to studies where researchers have discovered that acute sleep deprivation is actually a transient cure for depression. You are experiencing the same “high”. Forcing yourself to stay awake probably elevates brain biochemicals such as noradrenaline and dopamine that make you feel a sense of pleasure and also sharpen your cognition. However, this is probably not to be recommended in the long term.

For as long as I could remember (I’m in my 30s now), it took me on average 2-3 hours to fall asleep every night. My sleep has slightly improved since I started doing physical activities during the day, but it still takes me an hour or so to fall asleep. I also realize that I’m waking up multiple times during the middle of the night. I live right next to a busy street and several lamp posts outside, so that may be an issue.

Would earplugs help? If so, I’m willing to get the best one because the lack of sleep has been causing me brain fog. Any other suggestions?

Wei here: Thank you for the question. Indeed, physical activities are considered to be able to facilitate sleep and increase the quality of sleep. From your question I’m not sure on the exact time you go to bed. It is possible that your body clock is telling you to sleep at midnight, while you go to bed at around 10 pm for example, so it will take 2-3 hours to fall asleep. It might be helpful if you only go to bed when you actually feel sleepy instead of waiting and struggling in bed for too long. Struggling to fall asleep might create a negative association between where you sleep and not being able to sleep. It’s always recommended to create a good sleeping environment and reduce distractions e.g. noise level (earplugs might help with that) and intensity of the light. Hope you will get better sleep soon!

Is it true that there is a specific time that we should go to sleep? Some say before 10 pm, some say 11 pm, etc. Was wondering if that's just a myth?

Wei here: That’s a very good question, thank you. The short answer is yes, but the optimal bedtime varies. The duration of sleep and when we should go to sleep are largely related to genetics. Some people feel sleepy at 10pm while some people prefer to sleep around midnight. In general, regularity is important. Having a regular time you go to sleep will help your body to set the internal clock and increase the quality of sleep.

Have you done any research on "short sleepers"? For those who don't know, they're people who sleep for 4ish hours a night with no negative effects. They also tend to have a more sunny disposition.

Bill here - My colleagues Prof Simon Archer and Prof Derk-Jan Dijk at the University of Surrey are experts in this area, and they have studied many such people such as yourself. There are genetic reasons for short sleepers. But in general, you are a fascinating phenomenon! We would love to know why some people only need 4 hours while others (like me) need 8. But we simply don't know. But this kind of difference surely holds the clue to the functions of sleep.

How detrimental is shift work to your health?

1 month of 12 hour nights 7pm till 7am for 3 nights a week, then 1 month of days 7am till 7pm 3 days a week.

Always minding the kids on days off. So when on nights I have to constantly switch between nightshift mode and dayshift modes.

Bill here: Thank you for this. Unfortunately it is believed that shift work is detrimental to health in the short and long term. There have been many studies on human volunteers showing that shift work type conditions change their body biochemistry in many ways so that the wrong processes are active at the wrong time. I'm sorry I cannot give you a more positive answer.

I know that in the past guiness allowed competition not to sleep but it was banned after last one what happened to that man?

Bill here - Excellent question. That was Randy Gardner in 1964. He was kept up for 11 days and 25 minutes! But it was not a proper scientific experiment and his brain waves to show that he was sleeping were not measured. Apparently, nothing happened to him. He went to sleep for a day and a half and was fine. However, in reality, he probably had many microsleeps that were not detected. In fact, the urge to sleep is so strong that you absolutely have to go to sleep. When we have no sleep our cognition goes down, our mood gets worse, and we can't stop falling asleep after a certain point. So they are not allowed to do this type of Guinness book of records anymore. Sleep deprivation is a form of torture. In our lab, we are trying to understand why we have to go to sleep when we are sleep deprived. What are the chemicals in the brain that make us do this? But we don't know what they are yet.

Do you have any tips for me setting my new sleep schedule? I've recently changed from going to sleep at a random time (Usually from 1-4AM) and waking up at 11:30AM-1:30 PM (except on days where I work, where I have to wake up at 6am) to going to sleep at 10PM and waking up at 6AM every morning. The problem is, the days seem to last too long and I get very tired at around 2-3pm every day and it's a battle to stay awake until 10 so I can have a consistent schedule. I've been doing this for a couple of days now, will it get easier with time or is there another strategy I can use? I don't drink caffeine to stay awake, if that helps

Bill here - Thank you for this question. Definitely avoid going to sleep at random. Your strategy of 10 to 6 is an excellent one! I recommend a quick nap in the afternoon if your work allows it. Thats what I do! A short daytime nap (e.g. 20 mins) is believed to be beneficial to reduce the sleep pressure, and about an hour later you will feel much more awake.

When we sleep, sometimes the dream feel so surreal and some people call it lucid dream. May I ask, What cause lucid dream to happen and why does it happen?

Bill here: Thank you for asking this. This is a difficult but fascinating question. The short answer is we do not know. Most dreaming takes place in the stage of sleep named REM sleep - rapid eye movement sleep. But a lucid dream is one when you are extra aware of the dream. We are not sure why we have any types of dreams to be honest. Freud had a theory of dreams, but these days researchers think that dreaming is a byproduct of some other process. In lucid dreaming you are extra aware - possibly partially awake. But to be honest we simply do not know.

I sleep less than two hours a night, in 15-20 minute segments. I'm often awake for several days at a time without any at all. I had one sleep study that was said to be "useless" because I didn't sleep. Do you see this often? Any suggestions? (I have Ehlers-Danlos and Chiari.)

Bill here - This sounds fascinating from a scientific point of view, although I appreciate that you must be suffering extremely with your conditions. I have not heard of people that are awake for two days like this. I would suggest you keep trying to contact a sleep doctor. I am sorry I can't give a more specific answer.

About your research, how is it possible the study on animals' brain to reveal insights about human brain and sleep, especially its affects on dementia and Alzheimer's?

(coming from someone with no life science background - I know it is a naive question )

Bill here - Thank you for this question. We can learn alot about basic sleep physiology because mice and humans have similarly organized brains. So just like us, mice have wake, NREM and REM sleep and the organization of the brain and circuits would be expected to be similar. Mice can also get Alzheimer’s-like diseases and dementia - they get it in an accelerated way. And scientists have been quite successful in modeling dementia in mice. For example, mice get deposits of protein toxins (amyloid plaques and tau tangles) just like humans, and the neurons die in their brains in the same way as in humans. So it is feasible to look at how sleep deprivation influences the appearance of these toxins in mice.

I usually wake up just before my alarm and don't remember any dreams. Sometimes I'm woken up by the alarm out of a dream where I was very busy and I feel really tired, almost as if the dream busy-ness was me really bustling around doing stuff! Why do I feel so tired? (by the way it is super annoying to wake up feeling like you've already done a day's work!)

Wei here - Thanks for the question. Human sleep consists of two types: rapid-eye movement (REM) sleep and non-rapid eye movement (NREM) sleep which further includes 4 stages. NREM sleep is so-called deep sleep and REM sleep is when we usually dream. NREM and REM sleep cycle for about 1.5 hours and on average we can have 5 cycles in one night. The feeling we have and our energy level depend on when exactly we wake up. If we wake up in the middle of a deep sleep (NREM sleep), we are likely to feel tired. But if we wake up when the sleep cycle is just finished, so the end of REM sleep, we usually feel refreshed. Of course the exact time of each cycle for everyone is different, if you could figure out the best duration for yourself, you can potentially reduce the chance of feeling tired after sleep. Hope this helps!

I noticed my grandmother, as well as other family members, all started sleeping less and less as their Alzheimer’s worsened. (They would each wake up after a short period, and only sleep 3-5 hrs a day.) I’m curious if sleep disruption is a byproduct of Alzheimer’s or vice versa?

Bill here - Thank you for this question. Yes, sleep disruption is a byproduct of Alzheimer’s unfortunately. This is because as the disease progresses, all parts of the brain start to be affected. The brain circuits that regulate sleep in the base of the brain (the hypothalamus) start to degenerate and so sleep becomes fragmented. There is also a phenomenon called “sundowning” in the late afternoon or early evening, when a person with dementia may act for example, more aggressively. This has been shown to result from damage to the part of the hypothalamus that contains the circadian clock. It is interesting to consider whether poor sleep itself makes Alzheimer’s disease worse, or during the course of a lifetime makes it more likely to get the disease. Acute sleep deprivation raises the levels of amyloid toxin in the brain, the toxin that causes Alzheimers. This has been found in both humans and mice. We are investigating if chronic sleep deprivation in mice increases their chances of getting dementia.

I find I take an hour or more to fall asleep and my wife 10 minutes. Is there any way I can train myself to fall asleep quicker?

Bill here: Great question! It might depend on whether there are any distractions stopping you getting to sleep e.g. phone, light. Try and avoid these if you can. It might be that you are naturally a later sleeper than your wife. You could try going to bed later when you feel tired and not try to force going to sleep when you are not ready.

Have you done any research one naps vs sleep? When I was in college I spent a few months taking about four 1.5hr naps a day (roughly every 6hrs or so) and it was fantastic. I would have kept it up but once I graduated the traditional work schedule messed things up. When I thought about it, I felt it made sense since our ancestors (prehistoric man) probably took naps instead of sleeping for long periods due to living in the wild with constant threats (no idea how they really slept).

Wei here - That’s a very interesting question, thank you Hanzburger! We haven’t compared naps with continuous sleep directly in our lab. However, many labs observed a phenomenon called “siesta” in fruit flies and a similar effect on mice as well, which means a slight increase in sleep in the middle of the day. It is believed that the longer we stay awake, the more “sleep debt” we are accumulating. Taking a short nap is believed to efficiently reduce this “sleep debt” and reboot our energy level. So naps are recommended as long as it doesn’t affect your sleeping process at night. :)

How does our need to sleep compare with other vertebrates? I think all of us sleep in some form. How far back did evolution give us sleep?

Bill here - Great question. All vertebrates sleep, from fish through to us primates. We primates are unusual in having a block of sleep (e.g. 4 to 8 hours) all at once. Most animals have distributed sleep and wake over 24 hours. Dolphins sleep with half their brains at a time, because they have to keep swimming! Some migratory birds can suspend sleep while they fly extraordinary distances (scientists have recorded the brain waves of certain migratory birds to show this). It seems that all animals need to sleep (insects and jellyfish sleep, for example), but only mammals and birds have NREM and REM sleep. So sleep is doing something very important for the body and brain, we just don’t know what yet!

Have you carried out any research on adult sleep walking? I slept walked as a child and then it started again at 25yrs and is still happening 12 years later. I don't take any medication and sleep well otherwise.

Bill here - Great question. Sleep walking occurs during REM sleep. Normally this is the stage when we dream the most but our muscles are frozen (the technical term is “atonia”). So normally if you are dreaming that you are say running, you don't actually move. But for some unknown reason during sleep walking this inhibition of the muscles is lost and you start acting out your dreams. We do work on the brain circuits that generate REM sleep, but we ourselves have not worked on the circuits in the brain stem that stop your muscles working in REM sleep. Other colleagues around the world have and they know about what happens in great detail. Unfortunately, it is not yet understood why this mechanism of muscle atonia fails during sleepwalking.

Hi! I would like to ask why some people prefer to sleep and wake up later in the night/day, would we state that this is a circadian rhytm abnormality and except for environmental factors, are there evidence about the role that genetics play in distorted sleep patterns?

Bill here - Thank you for this question. The answer is yes. There are many genes that determine when we wake up early or late. For example, a colleague, prof. Simon Archer at the University of Surrey found that we humans have two versions of a gene called Period3 (Period3 short and period 3 long). People that have only the short gene wake up early. People that have only the long version can have delayed sleep phase syndrome. This is just one example of the many genes that researchers have now discovered that partly determine if we are “owls” or “larks”.

So I have been a terrible sleeper for as long as I can remember. Laying awake in bed for ages before I can fall asleep, and when I finally do, the slightest sound/noise wakes me up again.

Does this mean I might be prone to neurological disease?

Wei here - Thank you for the question. Indeed it has been reported previously that lack of sleep increases the risk of several neurological disorders including Alzheimer's disease. The hypothesis is that during sleep, toxins such as beta-amyloids are cleared and compromised sleep subsequently disturbs this process and leads to an accumulation of toxins. As you mentioned that you are a light sleeper since you could remember, I don’t think you need to be overly concerned about it as sleep is not the only factor deciding if we are likely to be prone to diseases. But it’s always recommended to keep a healthy lifestyle in general.

Is the conventional assumption that adults need to sleep 8 hours a day backed up by your research and findings?

Wei here: Thanks for the question. Although our work is mainly based on animals, it's generally recommended for adults to have 7 to 9 hours a day. The absolute amount of sleep required for individuals may vary.

What are your thoughts on sleep aids like ambien?

Bill here - Sleeping medication can be useful at certain times in our lives. For example, Ambien (zolpidem) does work and does induce fairly natural sleep. I have taken it myself and I know it works. So I have no problem with it for occasional use, provided it is OK with your doctor (please always check). However, it is not something you want to take as a habit to help you sleep. These drugs can be addictive and have side effects on your memory (they act on many parts of your brain, not just sleep centers). The best way to ensure regular sleep is to try and adopt good sleep hygiene. This means always try to go to bed at a certain time, avoid phones/tablets/tv in the bedroom. And maybe use a natural daylight lamp first thing in the morning. Do exercise as well if you can.

For the past few years, I've habitually had 4-5 hours of sleep a night, sometimes less. No real reason, just feel like there's not enough time in the day to do all the things I feel I need to do. I already know this is bad for me. As I am now 40, should I be taking sleep more seriously? I've never been one to really "sleep in" on the weekends - but if I did, would that help with the sleep deficit over the week?

Wei here - Hi JonLeung, thanks for posting the question. I think what you are describing is a very common scenario in modern society! We are getting busier and busier and the easiest solution for many people is to simply reduce the amount of sleep. It’s great to see that you’re thinking more about your sleep in terms of your health, and you might have already read that lacking sleep increases the risk of getting diabetes, neurological disorders and cardiovascular disease etc. The good news is, it’s never too late to improve your sleep.

In answer to your question about ‘sleeping in’, it would be helpful to reduce the “sleep debt” if you sleep for longer at the weekend. The only downside of doing this is that it might affect your rhythm and make it more difficult to get up in time on Mondays. But as long as it could help you and does not affect your performance on Monday, it’s a good idea!

What can someone do to make sure they fall asleep if they are at risk of Alzeimer's? My aunt is at risk due to the illness running rampant in my family. Menopause has been disturbing her sleep for years now and I guess she's in a pattern now where she can't sleep more than 2 hours at a time, about 4 in total per night. Brain MRI doesn't show any sign of alzeimer yet, she is 50, but she is aware of the importance of sleep and not sure what to do. She told me that drugs that typically make you sleep don't give you the right quality of sleep to help delay the onset of the disease. Is this true? Do you have any recommendations for her?

Bill here - Thanks for this important question. It is true that drugs such as Ambien (zolpidem) do not give sleep that is completely natural. It's best to use these drugs only occasionally and always with the consent of your doctor. Instead, the best thing while your aunt remains healthy is to try and make sure you have very good sleep “hygiene”. This can include going to bed at the same time every day, removing distractions around (phones, TV, light, noise etc.), taking regular exercise or starting the morning with a special daylight lamp that stimulates the circadian system.

Fellow sleep researcher here! One question I always like to ask, who would you say has influenced you the most?

Bill here - the Beatles!

I love this topic! 2 q's for you guys, Can exercise improve the function of the glymphatic system, and do you agree sleep should be targeted as a primary intervention for the management of chronic pain?

Bill here - Thanks very much for your enthusiasm! You have gone straight for a key question about the glymphatic system! I don't know the answer. But it should be investigated! For the management of chronic pain, there are studies that good sleep reduces the severity of pain. As you might know, there are actually no good drug treatments for chronic pain at the moment. So it seems sensible to advocate that sleep might have a calming effect on the pain, provided the pain is not disrupting the sleep too much.

Do mice snore? Based on cartoons I believe they do and it’s pretty cute.

Any evidence or studies on humans snoring when they sleep and the impact that has on their health / quality of sleep? I snore like a freight train. I’m also a deep sleeper when conditions are right.

Bill here - Ha! No idea! But I agree it’s cute! More seriously, there are sleep apnea models in mice. For example, my colleague Dr Ivan Rosenzweig at King’s College London works on one such model. Sleep apnea, rather than snoring per se, tends to be a problem, because the windpipe collapses during sleep, and the person does not get enough oxygen, which then triggers an emergency response to wake up. In the long term this is probably very damaging but can be easily solved with the right kind of positive air flow mask at night. Sleep apnea and snoring will of course be a problem for your partner who will also suffer sleep deprivation. But the fact that you can sleep deeply suggests you do not have sleep apnea. People with sleep apnea tend to wake up feeling unrefreshed and are often tired throughout the day.

Everyone knows that alcohol disrupts sleep. What I want to ask is, does alcohol ingested during the day time (let's say, 2-4 units) disrupt your sleep or is it just the alcohol ingested at night before bedtime (because then you will feel the acute effects of alcohol while sleeping)?

Bill here: Thanks for the question. Not completely sure on this. I would think (from my own experience!) that drinking alcohol at say lunch causes me to have a nap in the afternoon, then it's much more difficult for me to sleep in the evening. So indirectly, day time alcohol consumption will influence your nighttime sleep.

People with ADHD seem to have difficulty with sleep (myself included). Have you considered ADHD as part of your research?

In addition, do you know if there are any links between ADHD and Dementia/Alzheimer's and/or heart disease? Given that women have higher rates of heart disease and stroke, I've often wondered if this is tied to a reduction in sleep hours and quality (being up with children, anxiety/stress, doing things later at night when the house is asleep or early in the morning before they get up).

Wei here - Great questions! Yes, patients with ADHD usually have difficulties in sleep. In fact, patients with various neurological disorders all have deficits in sleep, such as intellectual disability and autism, Alzheimer's disease, Parkinson's disease etc. We haven’t found any neurological diseases without any sleep defects. Brain regions that are mostly affected by genetic mutations or aging-related degeneration are sleep-regulating areas, unfortunately. So yes, it would definitely be a very interesting research direction! Regarding ADHD and dementia, I’m not aware of direct evidence linking these two conditions though.

Hi there. I have a question about sleep deprivation and Alzheimer's disease. Could a person in their 20's and 30's develop Alzheimer-like symptoms due to being sleep deprived for years, such as having memory loss?

Bill here: Thank you for this question. That is the very thing we and other researchers are trying to investigate in mice - does long term sleep deprivation make it more likely to get dementia? We don't know the answer to this question yet. We know that short term sleep deprivation raises the levels of toxins (amyloid and tau proteins) in the brain after a night of sleep deprivation. We see this in mice and human volunteers. So the question is, what happens if you have poor sleep over decades? We don’t know to be honest. However, I do not think you would develop Alzheimer’s in your 20s and 30s even with poor sleep. Some unlucky people do get early onset Alzheimer’s disease, but this isn’t down to lack of sleep, rather that they are unlucky enough to have a gene mutation (which is quite rare).

What do you think about Matthew Walker's book for a layman like myself?

Bill here - I have read it myself and I like it! Its an engaging read. And it shows the immense interest people have in sleep as it became a best seller.

Is there any proof that music can effect dreams?

Also what type of effect if any does music play on waking up?

I notice if I go to sleep to calming music I'll usually have a good night's rest. However if that calming music is still playing when I wake it's harder to get out of bed.

Bill here - Interesting question! I think that while you are asleep your brain is still, to some extent processing the music, even if you are not conscious of it. If you are in a deep NREM sleep, I think music will not influence dreams. But if it has a certain kind of rhythm or sound it may infiltrate into lighter stages of sleep and so it could influence your sleep. Not sure about waking up.