Not getting enough sleep at night does more than just disrupt your internal clock and leave you feeling fatigued the next day — it can also impact the memory. While it’s known that getting enough sleep plays an integral role in our ability to form memories, researchers have also uncovered interesting links between lack of sleep and the negative impact that it can have on both short and long-term memory. As many as a third of Canadians get less than the recommended 7 to 9 hours of sleep each night, and the results can be detrimental — including having a severe impact on one’s ability to retain new information.
Sleep spindles, which are one to two-second electrical pulses that happen as many as 1,000 times per night, are responsible for taking in what we learn and shifting it from a limited space in our brain known as the hippocampus, to the brain’s hard drive known as the prefrontal cortex, where the memories are stored for future reference. When we sleep, the hippocampus goes through a reactivation phase in which it clears and makes space for us to take in new information, which can actually strengthen and enhance our memories even further. Unfortunately, for someone who doesn’t get enough sleep, they will have fewer sleep spindles, meaning that their ability to permanently retain information or remember new information becomes significantly disrupted.
As for how the memory actually works, it is broken down in three separate functions:
• Acquisition — When new information is introduced to the brain.
• Consolidation — When a memory becomes stable.
• Recall — The ability to consciously or unconsciously access stored information.
There are also four different stages of sleep:
• Stage 1 — The lightest stage of NREM (non-rapid eye movement) sleep which is defined by slower eye movements, as well as relaxed muscle tone and slower brain wave activity. During this stage it is easy to be awoken.
• Stage 2 — While still NREM sleep, you won’t wake as easily as you would during stage 1. During this stage your heart rate begins to slow and body temperature also decreases.
• Stage 3 — Deeper NREM sleep, and much more difficult to awaken someone during this stage. During this stage it is possible to talk in your sleep or even sleepwalk.
• Stage 4 — Also known as REM sleep (rapid eye movement), this is known as the dreaming stage of sleep. You can awake much more easily during the REM stage of sleep, and it is also often accompanied with grogginess.
During these various stages of sleep, memories are formed and cemented in different ways. If you’re not getting enough sleep, your ability to focus and learn is hindered. Furthermore, sleep is necessary if you want to be able to consolidate your memories. This and other studies conducted have shown that people who get the recommended amount of sleep, or even take naps during the day, are not only like to have an improved ability to acquire, consolidate and recall their memories, but also have improved performance at work, school, and even when playing sports. Adequate sleep is also essential for our fine motor skills, judgement, and physical reflexes. Essentially, we need sleep to survive — and while it may not always be attainable to get 7 to 9 hours of sleep each night, there are some steps you can take to improve your sleeping habits.