The Curse That Comes in the Night
Of all of the many things that I’ve written about blindness and vision loss on this blog, I have never touched on one of the most unusual and little known. Most people who are losing their vision have never heard of it and, therefore, don’t think of it as a possible consequence of their vision loss. If, however, they are still able to retain some small amount of vision, and it doesn’t take much at all, they will be able to escape it.
Simply put, the majority of people who are totally blind struggle to get a decent night’s sleep.
The explanation requires a digression into a little bit of basic science. I promise to keep it simple, painless, and short.
The circadian rhythm is your body’s 24-hour internal clock which controls your sleep-wake cycle. It prepares your body for a host of other processes, such as eating, but I promised to keep it simple so I’ll just concentrate on sleep. Your sleep-wake cycle is closely related to the environment. For example, daylight tells your internal clock it’s time to get up. When the sun sets, the dark tells your body it’s time to sleep.
Throughout most of human history, this worked pretty well – get up with the sun and go to bed with the dark, and it still works for most people in the world today.
Problems occur when something interferes with the ability of the body’s internal clock to sync with the twenty-four-hour day.
The closest most people will come to experiencing this is working the grave-yard shift or flying from the West to the East coast. (It is harder for the body to adjust going west to east than east to west because it is easier to delay sleep than to advance it.)
Most peoples’ “clocks,” which are actually a group of tens of thousands of nerve cells in your brain that sends signals to your body that it’s time to wake up or go to sleep, are in sync with the twenty-four-hour day. Under normal circumstances, this is what allows us to go to sleep and wake up on a fairly predictable schedule without ever thinking much about it.
If, however, something happens to interfere with the normal functioning of the circadian rhythm over time, an individual can develop what is called a non-24 sleep disorder.
I think you can see where I’m going with this. Under most circumstances, as long as you can see the sun coming up in the morning about the time you’re getting up and see it going down in the evening about the time you’re ending your day, your sleep pattern is probably going to be pretty predictable. You may have glitches from time-to-time, but these aren’t likely to be anything significant.
Even if someone’s vision is extremely poor, as long as they still retain enough vision to distinguish daylight from dark, they’re probably going to have a normal sleep pattern.
However, if they are totally blind and have lost the ability to tell when the sun has come up and when it has gone down, there is a strong likelihood that they experience non-24.
The Johns Hopkins Medical School estimates that, while perhaps at most 13% of the general population in the United States will experience “serious” sleep problems sometime in their lives, between 55% and 70% of totally blind people deal with non-24 sleep disorder, frequently for years, and, not uncommonly, for a lifetime.
Don’t think that this is something that can be “fixed” by taking an Ambien or some over-the-counter sleep aid. They do nothing to correct the circadian rhythm and so the underlying problem remains the same.
Lacking the ability to tell when the sun has gone down, the “internal clock” of the totally blind person isn’t a dependable guide as to when to go to sleep. He or she finds themselves going to sleep later and later every night and, since they likely have to get up at the same time every morning, the result is that, over time, their sleep is far shorter and much poorer. Tonight, they may go to sleep at 11:00, next week 11:30, next month 1:00, until, eventually, their sleep cycle has gone completely around the clock.
Not only is the quantity of sleep affected but so too is the quality. Because the natural rhythm of sleep is thrown off, people struggle to get truly restful sleep.
If you think all of this seems like much ado about nothing, just remember all the whining and complaining that goes on every time we lose one hour of sleep the one day a year we go on daylight saving time in the spring and imagine what your life would be like if you were making the switch every day of your life.
When I asked a friend who had taught blind children for years if she and her peers ever encountered non-24, she said, “It would be hard to not be aware of this issue because most of us have encountered blind preschoolers who want to sleep all day at school because they are up all night.”
Non-24 can never be cured. The best that can be hoped for is that it can be managed. Looking back, I think I’m pretty safe in saying that I first developed it shortly after I lost all of my vision more than twenty-five years ago. I went from sleeping seven hours a night to three or four. Six hours of very unsettled sleep was probably the closest I ever got to a good night.
Experts generally agree that melatonin, taken properly, can be a great aid in helping restore something like normal sleep, and this has certainly been my experience. Additionally, it’s worth consulting the guidance of medical professionals who specialize in the study of sleep abnormality. I’d particularly recommend
Insomnia: Restoring Restful Sleep – Harvard Health
Circadian Rhythm Sleep Disorders: Types, Symptoms and Management
From the Cleveland Clinic.
Incidentally, people who study sleep disorders report a sharp increase in the number of sighted people complaining of non-24 in recent years also. Why? All those folks staying up late and staring at the light from their phones and computer screens is throwing off their circadian rhythms. So, the next time you have trouble getting to sleep, shut off the iPhone and try reading an old-fashioned print book.