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Effects of Sleep Deprivation


Without sleep, the emotional centers of the brain dramatically overreact to negative experiences, researchers report in a recent issue of Current Biology. The hyperactive emotional response in sleep-deprived people stems from a shutdown of the prefrontal lobes, the executive center of the brain that normally keeps emotions under control. (It's long been known that learning and memory are impaired by lack of sleep.) The investigators had expected some increase in the brain's emotional reaction from lack of sleep, but they were stunned by its magnitude. The emotional centers of the brain were over 60 percent more reactive under conditions of sleep deprivation than they were in subjects who had obtained a normal night's sleep. 


Here's the way one of the researchers put it: "It is almost as though, without sleep, the brain reverts back to a more primitive pattern of activity, becoming unable to put emotional experiences into context and produce controlled, appropriate responses. Sleep deprivation fractures the brain mechanisms that regulate key aspects of our mental health. The bottom line is that sleep is not a luxury that we can optionally choose to take whenever we like. It is a biological necessity, and without it, there is only so far the band will stretch before it snaps, with both cognitive and emotional consequences." The scientists noted that some form of sleep disturbance is present in almost all psychiatric disorders. 


Sleep is intricately involved with the circadian rhythms of light and dark inscribed in all of our genes to allow us to live in synchrony with our environment. Almost all of the body's major systems run on circadian rhythms. Cardiovascular activity has a circadian pattern, as does body temperature, metabolic functions and liver and kidney processes. Yet, increasingly, because stimulation is so readily available around the clock, people override basic biorhythms and ignore the biological signals for sleep. Study after study has shown that we function best physiologically and psychologically when our internal cycles are well-synchronized with those of the external world. 


When we mess up sleep and wake cycles, there's a reason we feel "out of sorts." Yet, researchers find, the sleep patterns of Americans are getting worse, increasingly out of phase with the natural rhythm. People are staying up later than ever and, as adults put achievement pressures on kids, sleep disturbances occur at a progressively younger age. The same researchers also point out that the less people sleep, the more they get depressed. And the worsening of sleep among Americans has been accompanied by real increases in the incidence of clinical depression. 


Physical well-being is affected by sleep patterns as well. When our sleep gets out of synch with natural cycles of light and dark, the immune system is compromised. There's a higher likelihood of getting a cold or the flu. Hormones are in disarray. Stomach problems arise. These are not hypothetical problems; they are, in fact, the common complaints of those people who do shift work, experience jet lag, and suffer from insomnia. 


Staying in tune with natural cycles and getting enough sleep put people in line for peak performance. Failure to synchronize patterns of activity and stimulation with the body's natural rhythms puts a stress on the system. The remedy is hardly dramatic. Studies show that the best way to set the body clock is to plan exposure to natural light in the early part of the morning. By shutting off production of the hormone melatonin and regulating its circadian pattern of production, that's what allows people to fall asleep at night. 


Adapted from Hara Marano,

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