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?