Let’s think about this scenario. A first-year student at a top university wants to maintain their top 1% status, as in high school. Soon after the first midterm, they realize that the college courses are much more difficult than they thought. Even though they work hard, they are only at the class average. They look at their schedule, and decide to study more into the night, hoping to spend more time studying and memorizing all the important details. One week before the next exam, they start to feel sleepy in class, and it seems harder for them to remember information. The result of the second midterm is even worse, so they start to pull all-night studying to catch up. However, they start to feel sleepy in class, which gradually changes to missing classes. They start to find something in their mind has changed as well, as they become more irritated, and what used to fascinate them are no longer interesting. The final exam becomes the worst of all exams, despite that they have put the most efforts to prepare for the exam. They finally could not stand these any more, and decide to take a semester off.
This case is more dramatic than what happens in real life, but staying up late and the resulting lack of sleep may actually be more common than we think in colleges. In fact, more than half of college students reported being sleepy during the day in a research, compared with slightly more than a third in working adults (Oginska & Pokorski, 2006). Nonetheless, we must keep in mind that staying up brings more than sleepiness during the day.
First, as illustrated in the short story, one consequence of staying up late is the poorer performance in academic performance, probably due to the decreased ability to remember what’s learned in class. To students’ fright, research have shown that those who sleep less than 6 hours per day are reported to have 0.5/4.0 lower GPA, and that one hour of delayed waking up time can lead to at least 0.1/4.0 decreased GPA (Kelly, Kelly, & Clanton, 2001; Trockel, Barnes, & Egget, 2000).
But wait a minute, aren’t those students studying hard during the nights? How can extra devotion into studying compromise the results? The reason lies in our sleep cycle. Slow wave sleep is one of the five phases of our 90-minute sleep cycle when your brain waves are, namely, slow. We arrange our memories and store them accordingly in this phase. A higher quality of slow wave sleep can improve the functional performance of our hippocampus, a brain region for storing and holding memories.
Another brain region, the prefrontal cortex, is reported to hold memories of the relationships among items during slow wave sleep besides carrying out executive functions (Marshall, Heladóttir, Mölle & Born, 2006). Obviously, for people who stay up late, they have shorter sleep time and less slow wave sleep time. In fact, night owls may lose the last one or two slow wave sleep periods, and this diminished time for memorization keeps hippocampus and prefrontal cortex from carrying out their duties as they should have in normal lengths of sleep. Thus, remembering key points from classes will become increasingly hard for those who stay up late.
Second, chronic lack of sleep increases the chance for mental disorders. Our protagonist in the opening story is obviously a victim of mental changes due to lack of sleep, with more irritation and loss of interest in many things. These mental changes bring more stress to the already-high stress in academics. The increased level of cortisol (more commonly known as “the stress hormone”) alarms the brain with stress signals, and the brain sends the another hormone (ACTH) to all around the body, resulting in an overall rise of cortisol levels. Not surprisingly, cortisol levels are very high in people with depression or anxiety disorder, where lack of sleep may be a significant symptom in both mental disorders. Actually, early signs of mental state changes don’t even require staying up late for a semester, as a research showed that only 56 hours of continued consciousness (less than 3 days) in completely healthy humans could generate signs for anxiety, depression, and even paranoia (Khan-Greene, Killgore, Kamimori, Balkin, & Killgore, 2007). When we think of college students with incredible levels of academic stress and peer pressure, they already have high cortisol levels, sleeping less will exacerbate their stress even more easily, thereby making them more susceptible to mental disorders.
Therefore, for college students, staying up late does not only simply mean the sleepiness on the next morning. When a college student is not sleeping when they should be, their brains will not remember things as well as they expect. Furthermore, lack of sleep is itself a stressor in life, and even more so when academics brings in even more stress. Biologically speaking, the accumulation of stress makes college students more mentally vulnerable. Obviously, if you are not a college student, it does not mean that you can stay up late as you wish, either. Your basic physiology is no different from college students, and having sleep deficiency due to staying up late will cause similar physical and mental consequences to you as well. As a conclusion, since staying up late and sleeping less does not benefit in any approach, my advice is very simple and straightforward: it is not healthy to stay up late, and it will not be worthwhile.
Kelly, W. E., Kelly, K. E., & Clanton, R. C. (2001). The relationship between sleep length and grade-point average among college students. College Student Journal, 35(1), 84-86.
Kahn-Greene, E. T., Killgore, D. B., Kamimori, G. H., Balkin, T. J., & Killgore, W. D. (2007). The effects of sleep deprivation on symptoms of psychopathology in healthy adults. Sleep Medicine, 8(3), 215-221.
Marshall, L., Helgadóttir, H., Mölle, M., & Born, J. (2006). Boosting slow oscillations during sleep potentiates memory. Nature, 444(7119), 610.
Oginska, H., & Pokorski, J. (2006). Fatigue and mood correlates of sleep length in three age‐social groups: School children, students, and employees. Chronobiology International, 23(6), 1317-1328.
Trockel, M. T., Barnes, M. D., & Egget, D. L. (2000). Health-related variables and academic performance among first-year college students: implications for sleep and other behaviors. Journal of American College Health, 49(3), 125-131.
Featured image from blueridgemuse.com.