When the Body Wants to Sleep, but the Mind Is Still Awake
Shift workers suffer a unique dilemma when it comes to getting rest.
Posted Jul 25, 2018
We who live in a "daytime awake, nighttime asleep" world often forget about the millions of people who are working while we are sleeping, and then sleep as we go to work. A very early or very late taxi ride from the airport, or a nurse coming into your hospital room at 3 am, reminds us that a large part of the world lives with a totally different sleep/wake schedule. Forcing the body to adjust to even a small difference in time zones is difficult, as anyone who has flown from coast to coast with its three-hour time difference realizes. Imagine having to force one’s body to stay awake six or seven hours beyond normal sleep time, or go to sleep that many hours earlier than usual. Then consider how to endure this shift in waking and sleeping every 6 or 7 days, as you move from work to days off, and then back to work again. Just thinking about it causes one to feel insomnia or sleepiness coming on.
The health consequences of shift work are well known — obesity, diabetes, depression, elevated blood pressure, chronic sleepiness, cancer, and alcoholism, among others. Many people work evening or overnight shifts because of economic benefits, compatibility with child care needs (a mother works nights while the father is home with the kids), or because it is part of their job description, e.g. firefighters who never know when they may be on a fire truck rather than in bed at 2am.
Chronic sleepiness or insomnia are the most pervasive effects of shift work. Elaborate sleep, nap, awake, exercise, and eating schemes have been engineered to promote the appropriate wakefulness or sleepiness. For example, workers on their way home at 6 or 7 am are told to wear dark sunglasses to prevent light from destroying their melatonin levels, and thus make them wakeful. Conversely, starting a late-night shift in bright light supposedly jump starts alertness, because the body may be fooled into thinking it is daylight (unlikely, but one can hope).
One problem facing evening or night shift workers is the need to sleep almost as soon as they arrive home. They may sleep only for 3 or 4 hours, wake to carry out necessary daytime activities, and nap before leaving for work. In this respect, their sleep schedule differs significantly from those who work during the day, and then expect an uninterrupted night’s sleep.
When the day worker arrives home from work, he or she does not attempt to sleep within the first hour or so. Usually at least three or more hours elapse between walking in the door and getting into bed. Dinner, family, chores, desk work, social activities, and entertainment fill the hours before the need to sleep. But this is not the situation with the typical night shift worker who arrives home somewhere between 7 and 9am (depending on commuting time). They may have something light to eat, and then less than an hour or so later try to go to sleep.
Try is the operative word: The daylight hours destroy the body’s natural melatonin, the hormone that puts us to sleep. And the mind of the shift worker has not switched into the very calm, sort of daydreaming mode that precedes a gentle drift into slumber. Imagine coming home from your daytime job and being told to shut down your thinking, worrying, planning, and reviewing NOW and go to sleep. It’s impossible, yet this is what the shift worker is attempting to do.
Drugs such as Ambien induce sleep rapidly, but at the cost of waking grogginess and disruption of normal sleep cycles. Melatonin may be a better option, because it is the hormone that induces sleep at night. One problem is dose, because levels in the blood at night are around 0.3 mg. (“Melatonin the ‘light of night’ in human biology and adolescent idiopathic scoliosis,” Grivas, T., and Savvidou, O., Scoliosis. 2007; 2:6) Yet that dose might not be enough when taken as a supplement to cause the shift worker to fall asleep during the day. Doses as high as 5 mg have been proposed and, although they work, there is no information as to whether the body might stop producing its own melatonin because so much is coming in as a supplement.
Eating a starchy carbohydrate upon arriving home might potentiate sleep because of its effect, via serotonin activity, on calming the mind. When small amounts of carbohydrate are eaten (30-35 grams) such as in a small baked potato, a cup of instant oatmeal, or an English muffin with a teaspoon of jelly, the release of insulin allows an amino acid, tryptophan, to get into the brain. This in turn triggers the production of serotonin, and leads to shutting off an overly active mind. When the mind relaxes, so does the body and that obviously makes falling asleep much easier.
Since the process of digesting the carbohydrate takes about 30-45 minutes, eating a carbohydrate snack such as a small bag of pretzels or rice crackers on the way home from work will also allow the mind to be prepared to sleep upon arriving home.
The worse foods to eat before attempting to sleep are those that require much digestive energy. Fatty breakfast foods such as cheese omelets, bacon or sausage, and heavily buttered toast or biscuits are not good things to have wallowing in one’s stomach or intestinal tract while attempting to fall asleep. High protein foods will also prevent serotonin from being made. They should be saved for the wake-up meal before the shift begins again.
Shift workers sacrifice a lot to work while the rest of us rest. Let's hope they do not also have to sacrifice getting the sleep their bodies need.
“Efficacy and hypnotic effects of melatonin in shift-work nurses: double-blind, placebo-controlled crossover trial,” Sadeghniiat-Haghighi, K., Aminian, O., Pouryaghoub, G., Yazdi, Z., J of Circadian Rhythms 2008; 6:10