What really is sleep?

We all know what sleep is and what it looks like, but what goes on in the brain during sleep? You may have heard that it’s good for you; that it helps heal your brain. But how does it do this? What are dreams? You may have also heard that sleeping helps improve you memory, how does that work?

Phases

Sleeping is a repetitive cycle of varying brain activity. In a typical night the average person will go through 4-6 of these cycles.

• Stage 1: NREM (non-rapid eye movement) 1, this stage typically lasts 1-7 minutes and is really just the beginning of when you fall asleep. The body is not fully relaxed, but brain and body activities start to decrease.
• Stage2: NREM2, this typically lasts 10-25 minutes during the first cycle. The body drop sin temperature, and breathing and heart rate will slow down. Brain activity also starts to decrease.
• Stage 3: NREM3, this is known as deep sleep or slow-wave sleep. Muscle tone, breathing, and heart rate decrease greatly in this stage. Brain activity takes on large, and ‘slow-moving’ waves known as delta waves.
• Stage 4: REM (rapid eye movement). Brain activity during this stage mimics activity while awake, and muscle paralysis will set in. Even though the eyes remain closed they are moving quickly

REM Sleep

REM sleep is often regarded as the stage where a lot of the benefits of sleep occur. EEG analysis shows that memory consolidation pathways are activated during REM sleep. The more you learn throughout the day increased the amount of REM sleep during that night, indicating that REM sleep is important for learning and memory formation. You can read more about sleep cycles and REM here.

Pull an All-Nighter or Sleep?

Given the research showing that REM sleep can help consolidate memories, is it better to spend more time studying? Or is it better to study what you need then sleep on it? A lot of benefit can come from sleeping rather that studying all night long.

References

1. Stages of sleep: What happens in a sleep cycle. Sleep Foundation. (2023, March 2). Retrieved March 29, 2023

2. ScienceDaily. (2020, June 5). Memory consolidation during REM sleep. ScienceDaily. Retrieved March 29, 2023