To sleep, perchance to dream… most of us are aware of REM sleep, the stage of sleep where our brain activity is the most similar to wakefulness. We dream, as our eyes move rapidly behind our eyelids (not dream-related, as it turns out – the intense electrical activity in our brains simply stimulates the trigeminal nerve, causing our eyes to twitch rapidly). What most of us are not aware of is that REM sleep is just one stage of sleep out of four, and we cycle through all stages repeatedly through the night.
At the start of the night, we spend most of our time in Stage 4, or deep, slow-wave sleep, where the brain shuts down as the blood flow to it slows. Stage 4 sleep is especially critical for children and adolescents, as it is when growth and development takes place. Beyond growth, muscle repair and healing takes place as well, and our immune system kicks into high gear. Children who don’t get enough stage 4 sleep will miss more school due to colds and flus. Allowing children to have caffeine, especially after around 2PM, can prevent them from reaching stage 4 sleep during the night.
As the night progresses, we spend more and more time in REM sleep. Our neurons, or brain cells, are incredibly active, forming new networks and categorizing information. REM sleep helps with memory formation and retention of new material learned during the day, and it also helps to associate new material with prior learning. Finally, REM sleep is when neurotransmitters are replenished. Neurotransmitters are the chemicals that your brain uses to send messages from one neuron to another, and they are used up every day. Without enough REM sleep to replenish them, our ability to learn and remember material the next day is diminished.
So how much sleep should our students be getting?
School-aged children need 8-9 hours every night, and adolescents need between 9-10. Current data shows that most adolescents average around 5-6 hours, about a four hour deficit every night. That’s a lot of learning being lost.
