How much sleep do we need?

I like to sleep and can usually fall asleep pretty easily, unless there is something major that is bothering me. When I was still working, I had to get up early in the morning but now that I am retired, I luxuriate in waking up around that same time, but then rolling over for a couple more hours. The duration and quality of one’s sleep seems to be related to other health issues and so researchers have been looking at what we can learn about the role of sleep.

While you sleep, your body and brain undergo several important changes. Gradually, you get cooler. Your breathing and heart rate slow down. Chemicals that decrease your appetite are released so you don’t wake up for a midnight snack. In your bloodstream, growth hormones ramp up. Meanwhile, memories are formed, and other thoughts are forgotten. Brain fluid washes over your neurons, clearing away debris built up throughout the day.

In 2015, the National Sleep Foundation recommended that everyone between age 18 and 64 should get seven to nine hours of sleep. Children and teens need even more sleep. But senior citizens can get by just fine with a maximum of eight hours.

It seems that sleeping too little or too much may be an indicator of other problems.

Compared with people who get more than seven hours of sleep, people sleeping less than seven hours are more likely to develop cardiovascular disease, obesity, diabetes and Alzheimer’s disease. Those who sleep too little are also at greater risk of dying than people who got enough sleep. And sleeping too much has problems, too. Any more than nine hours nightly is associated with depression and even greater risk of death than sleeping too little.

There are many potential mechanisms that might explain why sleep deprivation is bad for your health. Not getting enough sleep deprives you of a blood pressure medication that no amount of money can buy. That is, a good night’s sleep significantly lowers blood pressure, reducing risk of stroke and heart attacks. Skipping sleep also disrupts the release of hunger-suppressing hormones and increases appetite, especially for fatty and sugary foods. So not getting enough sleep can lead to weight gain and associated complications. One night of limited sleep also decreases the number of cancer-fighting cellsin your immune system.

There are many unanswered questions, such as how much it matters whether one sleeps without a break or fitfully, whether one sleeps soundly or restlessly, and whether daytime naps (something that I can do quite easily)can compensate for poor sleep in the night. It seems like sleeping a lot on weekends does not compensate for lack of sleep during the week. Does just lying in bed in a drowsy state count as sleep? Some of my nine hours is spent after I wake up, when I just lie in bed thinking about stuff and planning the day. I dream a lot and sometimes I use that initial waking up time to try to recall a particularly interesting dream in detail and understand what events in real life in the recent past may have been the cause of that dream’s plot. I find that a fun, investigatory exercise. But can it count as sleep?

Even though I am a senior citizen, I sleep about nine hours per night, more than the guidelines suggest though of course, I wake up maybe a couple of times and return to sleep. Often, when I wake up in the middle of the night, I think about some physics or math issue that I have been struggling to understand and often arrive at a new possible avenue for attacking the problem that I implement the next day.

I tend to belong to the school that believes in listening to your body. If I get up out of bed feeling refreshed and do not feel tired and listless during the day, I take that as a sign that I have had enough sleep the previous night.

Shakespeare wrote quite a bit about sleep and dreams. I love this particular quote about sleep, even though it is said just after Macbeth has murdered King Duncan while he was asleep.

Sleep that knits up the ravell’d sleave of care,
The death of each day’s life, sore labour’s bath,
Balm of hurt minds, great nature’s second course,
Chief nourisher in life’s feast.

That Shakespeare had promise as a writer, a real way with words and ideas. I wonder what became of him?


  1. mastmaker says

    Did you just describe your sleep habits or mine? Except for the length (I can only sleep about 6 hours a day + some afternoon nap), you might very well have described my sleep pattern in GREAT detail! Solving problems (work or fun) in the middle of sleep is simply glorious. Only problem is that we tend to forget the solution (and sometimes the problem as well) by the morning. 🙂

  2. mastmaker says

    Forgot to add an interesting tidbit: If you don’t try to recall the dream AS SOON AS you wake up, it is no use. Any other fleeting thought -- even one as short as a couple of seconds -- will obscure the dream and it is lost forever!

  3. anat says

    I have rarely had a good night’s sleep in over a decade. I’m trying to go to bed earlier and otherwise improve sleep hygiene, but it still takes me a long time to fall asleep and I wake up multiple times most nights. I try to take it philosophically.

  4. mnb0 says

    “it is lost forever”
    Which almost always is a good thing for me.
    I’ve taken it two steps further: I not only taught myself to forget my dreams immediately but also to wake up quickly when a dream (by far not always nightmares) becomes too vivid. This way my day starts better or fall asleep again much quicker when the dream came in the middle of the night.

  5. Rob Grigjanis says

    I loves me some Shakespeare, but regarding sleep, my favourite snippet is the Edith Hamilton translation from Aeschylus’ Agamemnon;

    God, whose law it is
    that he who learns must suffer.
    And even in our sleep, pain that cannot forget
    falls drop by drop upon the heart,
    and in our own despite, against our will,
    comes wisdom to us by the awful grace of God.

  6. anat says

    mnb0 @4:

    My husband is the opposite. He discovered that taking various pre-biotics such as resistant starch a few hours before bedtime pretty much ensure that he has vivid, complex dreams (usually not nightmares). He has been cultivating this so as to turn his sleep time into a form of enjoyable activity.

    I OTOH rarely recall dreams, regardless of pre-biotics use.

  7. file thirteen says

    I don’t have them often, but the dreams that have had the most impact on me are what I call “serial” dreams, where the next occurs in the same environment as one previous, and sometimes right at the point the last one left off. This despite me not having had a previous episode of the dream for weeks or months or even years.

    Anyone else have lucid dreams, when you realise you’re dreaming and can, to some extent, control what happens? It’s more of a disappointment if I get the ability to fly in my dream and realise I must be dreaming than if I fool myself into thinking I’m awake and it’s really happening, but in the former case I do get to rescript anything that I don’t approve of.

  8. Mano Singham says

    file thirteen,

    Sometime ago I wrote a more detailed post about dreams and I discussed lucid dreams and the fact that some people claim you can train yourself to have them and even control the events in them, though apparently it has its downsides.

    I have never had a lucid or serial dream.

  9. rockwhisperer says

    Pain often disrupts my sleep. I take one of the milder opioids for pain management (besides other, non-addictive meds), and I also take medication for peripheral neuropathy. Some nights they work. Some nights they don’t. Neither my doctor nor I want to increase the dosage of the opioid or switch to a stronger one, at least not right now. The neuropathy med makes me scatterbrained at higher doses. I like being able to think clearly.

    But damn, after a difficult sleep night, I am useless the next day. The air seems like mud, the simplest task is almost overwhelming, and I end up finishing the day with a profound sense of non-accomplishment. I remember cruising through undergraduate university quarters on 6 hours of sleep (at most) each night, and working outrageous hours on very little sleep in my 20s. Even in my late 40s, when I attended graduate school for an MS, I could occasionally take a very short night in stride. I look back on those days with longing.

  10. Mano Singham says


    Pain is a real sleep killer and I am sorry that you seem to have a chronic condition that causes it. That must be really tough to deal with.

  11. says

    The Greek philosopher Diogenes of Sinope was once asked, “What is the best time to eat dinner?” Diogenes’s response was, “If you’re rich, when you like. If you’re poor, when you can.

    The same applies to sleep. Sleep, like food, is a necessity to survive, but some suffer sleep poverty for a variety of reasons, mostly work and medical. Wouldn’t the 1%ers love to emulate the Chinese and have everyone working a 996 schedule until they die from exhaustion?

    Like WMD Kitty, I have my own medical issues, but post-concussion symptoms. I have difficulty doing nothing or passive involvement. I haven’t watched TV or movies in years because I can’t sit through them. The same goes for sleep, I can’t just lie in bed and wait. If I’m not ready to fall asleep within half an hour (usually because of exhaustion), I’ll be up for hours and things get even worse. It makes me glad I’m older (52) and REM sleep tends to comes earlier.

  12. VolcanoMan says

    @rockwhisperer (love the name, btw…I’m a bit of a geology nerd myself -- as you can probably tell from my own handle, I’ve climbed a few volcanoes, some erupting, and have also collected rock and mineral specimens from 4 continents, plus Hawaii and Iceland…a rough estimate of the weight of my collection is in the 300-500 lb range, which believe me, is a HUGE pain in the butt to relocate when I move residences).

    Anyway, I also suffer from chronic pain (mostly, but not exclusively neuropathy) that requires codeine (time release) and gabapentin to mitigate, but I count myself lucky that it rarely keeps me awake (a fact I attribute to the elephant-tranquilizing dose I am currently taking of each medication). Fortunately, I live in Canada where governments have (so far) left people like me alone…I know that the opioid epidemic has led to plenty of Americans in chronic pain increasingly being scrutinized, their doctors’ judgement questioned, their supplies sometimes cut off or significantly reduced (a fact which forces some people to seek illicit routes to treating their crippling condition). So I sleep fine now (maybe too fine -- sometimes I can put in 12 hours of sleep with just a couple of small bathroom breaks interspersed therein). But I do worry about the future, as there is no guarantee that what works today won’t be ineffectual in 10 or 20 years, and certainly my current doctor (who is kind and understanding and doesn’t question my need for pain management) will eventually retire and I may not be able to find a replacement who is as accomodating.

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