Another school year is coming to a close and students are cracking the books to get the high scores they need. It is common knowledge about the restorative powers of sleep for the body but it’s becoming even more apparent the connection between sleep and memory. Getting enough sleep is essential to learning and retaining facts – especially for test taking. To find out just how much sleep students should be getting, we chatted with Sudha Tallavajhula, M.D., Assistant Professor in the Department of Neurology at McGovern Medical School at UTHealth and Medical Director of the TIRR Memorial Hermann Neurological Sleep Medicine Center.
Q. How much sleep do people need?
Dr. Tallavajhula: The American Academy of Sleep Medicine recommends that adults ages 18-60 get at least 7 hours of sleep per night. For optimal health and daytime alertness, middle and high school students need considerably more sleep as a rule — 9 to 10 hours per night. The Academy reports that Centers for Disease Control data shows that 2/3 of teens don’t get the sleep they need.
Q. How does sleep impact your ability to remember facts and figures?
Dr. Tallavajhula: Memory is composed largely of learning, consolidation and recall. Learning and recall occur during wakefulness. Consolidation of new memories and knowledge takes place during deep sleep. There are two kinds of deep sleep: Slow wave (early) and the REM (later in the night). REM sleep is associated most with dreaming. Each kind of deep sleep is important for building memories.
Q. What role does the hippocampus play in making memories and retaining knowledge?
Dr. Tallavajhula: Think of the hippocampus region of your brain as your hard drive. When you learn new details and facts, they are processed in the hippocampus and surrounding structures, to a large extent in sleep. That’s why the hippocampus is critical to memory retention of facts. When you come up short on sleep, not only will it take you longer to remember the same data so your efficiency is decreased, it also does not consolidate that new data as well.
Q. Why is it important to get a good sleep BEFORE learning as well as AFTER?
Dr. Tallavajhula: Sleep is related to school performance and a student’s ability to pay attention. Students who don’t get enough sleep often have trouble concentrating and remembering details. The human brain requires sleep to pick up new details and to consolidate memories. Both deep sleep stages are critical to memory retention. The initial slow wave deep sleep (without dreams) transitions into more active REM (dream sleep
Q. How does pulling an all-nighter affect a student’s ability to learn?
Dr. Tallavajhula: If the hippocampus is your hard drive, you also have a server where all the details get stored eventually. This server is located in your brain’s frontal lobes. Transfer of data from the hippocampus to frontal lobes or long-term memory storage is highly dependent on sleep. Without sleep, transfer of memories for long-term retrieval is impaired and the information gets lost. During initial stages of deep sleep (i.e., Stage 3 sleep), memory for categorical data (details and facts) is most facilitated. Later in the night during REM sleep, you dream more and consolidate skill based learning, playing music, etc.
Q. Why is it important to turn off electronic devices long before bed time?
Dr. Tallavajhula: Having difficulty going to sleep is common among middle and high school students due to physiological reasons and hormonal changes that teens experience. These changes cause delayed sleep stage. That’s why teens want to stay up later, making it harder to get enough sleep. Electronic devices emit light that can disrupt the sleep cycle further. Q. How does blue light emitted from electronic devices keep you from going to sleep?
Dr. Tallavajhula: Melatonin levels in the body surge at bedtime. Melatonin is secreted from the pineal gland in response as the environment gets darker. Light, especially short-wavelength (blue) light emitted from electronic devices, prevents the pineal gland from releasing melatonin needed to sleep. Melatonin levels affect the body’s circadian clock that tells us when to sleep and wake up. When blue light disrupts melatonin levels, it shifts the phases of the circadian clock, making it harder to go to sleep. That’s why it’s so important for teens to start shutting off electronic devices 2 to 3 hours prior to bedtime.
Q. Does napping during the day help or hurt memory retention?
Dr. Tallavajhula: If you get enough, undisrupted sleep at night, there should usually be not much of a need for daytime napping. However, all of us experience a circadian dip at around 2-3 p.m. Napping is, in fact, a tradition in certain cultures and has been shown to improve learning. If you do nap, keep it short – not more than 20 to 30 minutes. You don’t want to fall into the Stage 3 or REM sleep because you will wake up groggy. If you’ve started to dream, it signals you’ve napped too long. The best way to know if you’re getting enough sleep is how you feel and perform the next day.
To learn more about how to prevent sleep disorders, visit one of Memorial Hermann Sleep Disorders Centers’ 11 Houston-area locations.