Hey Professor: The Sleepers

With reading period upon us and many exams fast approaching, long nights in are becoming staples in every undergraduate’s life. The trendiest bags at the moment are the ones under everyone’s eyes. But is it better to choose an extra hour of studying over an extra hour of sleep? When does an all-nighter do more harm than good?Associate Professor of Psychiatry Robert Stickgold ’66 answers these questions in his Medical School course, MBB980: “Conscious States: Waking, Sleeping, and Dreaming.” In 2010, he gave a TedTalk on the subject of sleep and memory. FM asked him how to optimize our sleep and studying schedules.

Fifteen Minutes: How many hours should we sleep each night to perform at our best?

Stickgold: I don’t know, because it really varies from person to person. But on average to function properly, each of us needs about eight hours of sleep a night.

FM: What’s the best way to make the most of the sleep you do get?

RS: Consistency is key. Emily Hogeland ’07, an undergraduate MBB student, studied a select group of students taking inorganic chemistry at Harvard over the summer, and found that the students who performed the best were the ones who had a fairly consistent sleep schedule. This means getting seven hours a night for four nights in a row before your exam will leave you feeling much better than if you get five, then six, then two, then seven hours of sleep in the days preceding your exam.

FM: If I have a 9 a.m. exam the Monday after reading period, how should I prepare myself to be awake and alert so early in the morning?

RS: By going to sleep at a reasonable hour and getting up before 9 a.m. the three to four nights before your exam, you will establish a pattern for your brain that will make getting up and focusing at 9 a.m. much easier. If you are getting the proper amount of sleep, but always going to bed at 2 a.m. and getting up at 10 a.m., it is going to be extremely difficult to force yourself to go to bed at a reasonable time the night before [your exam] and to wake up early the morning of the exam. This is because your brain and internal clock are used to the pattern you’ve created. The feeling of trying to break that pattern is very similar to jet lag, because of the adjustment your body must make to your new sleep schedule.

FM: What’s the minimum amount of sleep you would recommend for one night?

RS: If you get six hours you will suffer, but you will survive. However, [with] anything less than that, you are at risk to make very silly mistakes and to possibly even fall asleep during your exam. When I was an undergrad I accidentally slept through a one-hour physics exam because I stayed up much too late the night before.

Additionally, your brain makes a plan every night for how much sleep you are going to get based on how much you’ve gotten in the previous few nights, and then decides how it will process your memories from the day. For this reason, getting four hours of sleep catches the brain off guard and it is unable to complete all of the memory processing it had planned.

FM: What are your thoughts on using caffeine to stay awake longer and to feel more alert?

RS: There are two very important things you need to understand about sleep before I answer this question. First, sleep is meant to prepare you and your brain for the next day. As most people will tell you, if you don’t get enough sleep, the next day you feel like shit. It is extremely difficult to maintain focus and alertness, and your functionality is very low. Second, while you sleep your brain is actively processing information. Your brain makes connections between different ideas...and identifies what is important, so the next day your memory and synthesis skills are greatly improved. All of that being said, caffeine and other stimulants may simulate alertness, but they cannot make up for the memory processing you miss out on by not sleeping.

FM: What are your thoughts on naps?

RS: I love naps! A 90 minute nap provides as much memory processing as a full night of sleep, but only if you’re not severely sleep deprived. Additionally, a 90-minute nap is for some reason much more effective than a four-hour one for processing memory. This is likely because the brain is allowed to go through both REM and non-REM sleep. However, if you are just looking to increase your alertness, power naps are great. As little as 15 minutes of sleep can give the feeling of rejuvenation and increased alertness.

FM: What would you say to a student about to pull an all-nighter?

RS: Make sure that the all-nighter is actually necessary. If the test you have to take the following day contains mostly spit-back questions where you have to regurgitate memorized information then, OK, go for it, but pray you don’t fall asleep in that exam tomorrow. If the questions on the test are going to force you to make connections between information that you have never made before, such as an unexpected essay prompt or solving a math problem based on intuition, then an all-nighter is a bad idea because you need to get sleep in order to make connections between the information, and to process your memories of it.

FM: Is there anything else you would like students to understand about how the amount of sleep they get affects their cognitive functioning?

RS: Let me walk you through some math. If you decide to get six hours of sleep, rather than four, you are getting 50 percent more sleep that night. However, you are also only able to study for 18 hours, rather than 20, a 10 percent decrease in the amount of time you are awake and studying. The most important thing about this concept to understand is that if you can study 10 percent more efficiently with six hours of sleep then you have broken even, and I can guarantee you that you will be a minimum of 10 percent more efficient, if not more.

FM translation: Go to bed.