For most students, college life is a balancing act among academic demands, social pursuits, and employment. And it often seems that there is just not enough time in the day to get everything accomplished. Thus, many of us steal time from one of our most important daily activities in an attempt to shorten our lengthy “to do” lists. This daily “necessity” has been shown to impact cognitive performance, mood, cardiovascular health, hormone secretion affecting metabolism, and the body’s immune system. While browsing my Facebook newsfeed the other morning, I came upon a status update that seemed to best embody the relationship between the overworked college student and this frequently undervalued physiological requirement – “Sleep is overrated. Who needs sleep anyway?”
It’s a good question, and perhaps in order to answer it, we should begin with a discussion of sleep regulation. The National Sleep Foundation (hereafter NSF, not to be confused with the National Science Foundation) has released a booklet entitled the “Sleep-Wake Cycle: Its Physiology and Impact on Health.” The following information is a more college-relevant summary and interpretation of their explanation.
The sleep-wake cycle, “which consists of roughly eight hours of nocturnal sleep and 16 hours of daytime wakefulness in humans,” is governed by sleep homeostasis and circadian rhythms. Homeostasis is the body’s way of keeping internal conditions, such as temperature, fairly constant, and scientists know that sleep is also controlled in a homeostatic manner. Essentially, once you wake up, your body begins to accrue a drive for sleep. The longer you stay awake, the greater this drive becomes. At a certain point, it grows so strong that you cannot help but close your eyes. It’s similar to spending time at your favorite pub. The longer you sit at the bar, the more your tab increases, and eventually you must pay back what you owe. Just like the monetary value on your bill is a measure of your debt, it is believed that the amount of the chemical adenosine in your blood may help your body to monitor your “sleep deficit.”
Circadian rhythms refer to the physiological and behavioral changes that occur over a 24-hour cycle in the human body. The biological clock responsible for overseeing these rhythms is a group of neurons located in the hypothalamus called the suprachiasmatic nucleus. This clock is affected by environmental signals as well as lifestyle and scheduling choices. But the presence or absence of light is the biggest factor determining how it is set, which then impacts our desire to awaken or to sleep. Anyone who has ever experienced jet lag can appreciate the power (and fury) of disrupted circadian rhythms.
As the NSF explains, “Thus the homeostatic system tends to make us sleepier as time goes on throughout the waking period, regardless of whether it’s night or day, while the circadian system tends to keep us awake as long as there is daylight, prompting us to sleep as soon as it becomes dark.
Because of the complexity of this interaction, it is generally agreed that sleep quality and restfulness are best when the sleep schedule is regularly synchronized to the internal circadian rhythms and that of the external light-dark cycle – when we try to go to bed and wake up at around the same time each day, even on days off and weekends.”
Now that we have an understanding of the physiological underpinnings of sleep, it is time to explore its significance and influence. What issues arise when you skimp on sleep? Is there any scientific support for the importance of a good night’s rest before an exam? In an e-mail, Joe Burdo, a professor in the biology department, said, “Even though sleep has been intensely studied for decades, we still don’t know exactly why we need to sleep. We do know that a lack of sleep causes memory, attention, and coordination problems, similar to those seen with alcohol intoxication. It does appear that sleep is crucial for memory consolidation, which means that the signaling pathways between our neurons that encode our important memories from that day grow stronger. This has practical implications for students trying to learn new and complex information. If you try to stay up all night and cram for a test, by skipping sleep altogether or just getting a few hours, you’ll end up forgetting a lot of what you tried to learn. You’re much better off ‘sleeping on it’ for a full night to let those memories solidify in your mind,” he said.
In addition to memory consolidation and attention difficulties, a lack of sleep has also been associated with a wide array of negative side effects. The NSF cites a variety of studies showing that sleep deprivation causes increased stress, anger, and mental burnout, along with alterations in hormone release that are believed to be linked to obesity and diabetes. Even our immune systems are not exempt from the consequences of a lack of sleep, as revealed by another study which reported that the effectiveness of flu vaccines was drastically delayed in sleep-deprived men when compared to well-rested individuals. If this is not enough, cardiovascular disease is also thought to be influenced by sleep loss. Thus, examining the repercussions of sleep deprivation has led scientists to believe that a good night’s rest is necessary for the body’s proper functioning and overall health.
So how much sleep should you be getting each night? “Individuals have widely varying sleep / wake patterns, meaning that some are night owls who are more productive at night, some are larks who are more productive early in the day, and many people fall somewhere in between,” Burdo said. “This pattern also changes with age. In general, college age young adults tend to be night owls, but still need around nine hours of sleep a night to be most productive and keep memories the strongest.”
Sleep and its physiological foundations are a truly interesting and rather mysterious topic of scientific research. Although this article does not delve into the stages of sleep or “sleep architecture,” which details the events and patterns of rapid eye movement (REM) sleep and non-REM sleep, I encourage any interested readers to visit the NSF’s Web site to learn more about this subject and a number of other related matters.