Anybody who has ever tossed and turned after a rough day at work knows that stress can make it hard to get a good night's sleep. But the connection between sleep and stress is a two-way street. Just as surely as stress interrupts sleep, lack of sleep can be an uncomfortably large source of stress.
People working night shifts could be Exhibit A in the trial of sleep vs. stress. Humans aren't meant to be nocturnal, and people who work at night struggle to get enough sleep. As reported in the book Principles and Practice of Sleep Medicine (Elsevier/Saunders, 2005), night workers average five to 10 hours less sleep per week than other workers. The sleep they do get is often fitful. This problem is common enough to have a formal name: shift work sleep disorder.
Whether you're a long-haul trucker driving through the night or a student pulling an all-nighter to finish a paper, the shortfall of deep, restful sleep exacts a heavy toll, both emotionally and physically. As reported in Medscape Neurology and Neurosurgery, people who work night shifts are especially prone to stress, both on and off the job. Not surprisingly, they're also vulnerable to a wide range of stress-related conditions, including depression, heart disease, high blood pressure, stomach problems, weakened immune systems, and infertility.
Stress and sleep: The inside story
No matter what your age or occupation, a lack of sleep will throw your system off balance. To fully understand the consequences, it helps to take a quick look at the inside story of stress and sleep.
Just as the Pony Express relied on a series of riders to deliver mail across the Old West, the body uses a chain of chemicals to send messages of stress. First, the brain releases a hormone called CRH. This hormone prompts the pituitary gland to produce ACTH -- the next link in the stress chain reaction. ACTH is the messenger that tells the adrenal gland to release adrenaline and other stress hormones. These are the hormones that make a person feel "stressed out." They're also the hormones that, over time, can set the stage for stress-related illnesses.
A good night's sleep seems to block this chain reaction. As Stanford stress expert Robert Sapolsky describes in his book Why Zebras Don't Get Ulcers (Henry Holt, 2004), there's "decent evidence" that the same brain chemical that brings on deep sleep also tells the pituitary gland to slow down the production of ACTH. As a result, the adrenal gland never gets the signal to pump out stress hormones, and the body gets a chance to truly rest.
Interestingly, the part of the brain that houses the stress signal becomes more active during the dreaming (REM) stage of sleep, presumably to help fuel the startling visions that go on in our heads.
The toll of tossing and turning
If you don't get enough deep sleep, you're missing a chance to take a break from stress. Losing sleep might even send your levels of stress hormones in the wrong direction. Although research has been mixed so far, one study published in 1997 in the journal Sleep found that sleep deprivation boosted stress hormones the next evening.
It doesn't take a research study to show that missing sleep can make a person miserable. We've all felt the consequences: drowsiness, irritability, and a fog that just won't lift. Stress hormones block storage of short-term memories, which may explain why sleep-deprived people notoriously have trouble holding onto thoughts, much to the chagrin of students who cram all night for a test.
Missing one night's sleep is one thing; struggling with sleeplessness for weeks or months will really turn up the volume on stress. A study of insomniacs published in the Journal of Clinical Endocrinology & Metabolism found that those with the worst sleep produced especially large amounts of ACTH and stress hormones throughout the day and night. The levels of stress hormones -- and, thus, levels of stress -- were highest from afternoon until early night, a time when most people get to wind down.
People with insomnia feel more stressed out than people who have no trouble sleeping at night. As reported in the Journal of Clinical Endocrinology & Metabolism, people who sleep soundly enjoy a daily reprieve from stress hormones. For insomniacs, however, hormone levels stay high all day long.
With stress messengers literally coursing through their veins, its no surprise that insomniacs often feel frazzled. A study of 772 men and women of all ages published in the journal Sleep found that people who suffered from insomnia were 17 times more likely than sound sleepers to have anxiety problems.
Sleeping away stress
If you're feeling stressed out, getting enough sleep should be one of your top priorities. Try to get at least eight hours of sleep every night, even if you feel like you can "get by" on less. Of course, putting sleep on your schedule is only the first step. The National Sleep Foundation recommends "winding down" for an hour or two before bed -- no catching up on work, no phone calls. Also, you should reserve your bedroom for sleep or sex, not "waking" activities such as working or watching TV. Don't go to bed unless you actually feel tired. And if you find yourself wide awake between the sheets, get up and do something else until you feel sleepy again.
For shift workers, sleep can be especially elusive. The National Sleep Foundation offers special sleep tips for the graveyard shift: Sleep in a dark room (or wear a mask or dark glasses), use earplugs to block out sound, go to bed at the same time every day, and avoid caffeine or alcohol before bedtime.
Good sleep is worth the effort. Anyway you look at it, rest is better than stress.
Sapolsky, R.M. Why Zebras Dont Get Ulcers. Third Edition. Henry Holt and Company, New York. 2004.
Vgontzas, A.N. et al. Chronic insomnia is associated with nyctohemeral activation of the hypothalamic-pituatary-adrenal axis: clinical implications. Journal of Clinical Endocrinology & Metabolismm. August 2001. 86(8): 3787-3794.
Johnston, S.L. Societal and workplace consequences of insomnia, sleepiness, and fatigue. Medscape Neurology & Neurosurgery. September, 2005.
Leproult, R. et al. Sleep loss results in an elevation of cortisol levels the next evening. Sleep. 1997. 20: 865-870.
Taylor, D.J. et al. Epidemiology of insomnia, depression, and anxiety. Sleep. November 1, 2005. 28(11): 1457-1464.
National Sleep Foundation. Sleep and stress.
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National Sleep Foundation. ABCs of ZZZZ when you can't sleep.
Caltech Health Education. Got sleep?