In the Ted Talk I watched that was made by Sara Mednick, she discussed the science behind naps and the different stages as naps. There are 90 minute sleep cycles with 4 stages in each. Since a nap can range anywhere from 5 minutes to 3 hours, some naps can go through the full sleep cycles, or just a few of the stages.

The stages are as follows:

Stage 1: lasts around 2-5 minutes. This is the beginning stage where you are starting to fall asleep so nothing important really happens yet.

Stage 2: lasts about 30 minutes and is where the body temperature drops, muscles relax, breathing and heart rate become more regular. This is where biological changes start to happen. Neurons start creating waves of activity known as sleep spindles. Stage 2 sleep is associated with “long-term potentiation”, a process that is known to strengthen the synapses between neurons, which is also essential for learning.

Stage 3: lasts about 20-30 minutes and is the deepest stage of sleep. During Stage 3, multiple parts of the brain work together to transfer information from short-term memory storage to long-term memory storage, which stabilizes and strengthens your long-term memory. However, stage 3 is the most difficult to wake up from.

REM sleep: 10-20 minutes. The brain becomes as active as it does when you’re awake. Once REM is over, that is the end of the sleep cycle.

Now the pressing question about whether taking a nap is good for you. It depends on a few things, especially which stages the nap includes. If you take a 20-30 minute nap, that mostly includes stages 1 and 2, meaning that it would be relatively easy to wake up from since you have not entered the deep Stage 3. A 30-60 minute nap has the benefits of Stage 2, but also takes you deeper as you enter Stage 3. Even though a 30-60 minute nap will have cognitive benefits as your long-term memory strengthens, those benefits won’t kick in until around 15 minutes after you wake up. 60-90 minute naps enter the REM stage, meaning the prefrontal cortex, which is responsible for inhibition and cognitive control, becomes less active. The amygdala, responsible for emotion and motivation, are highly active. The combination of these two things are what causes you to have bizarre dreams while asleep because your inhibitions are lowered and your emotions are high.

The time of day also plays an important role on naps. As our day goes on, our need for a deep/REM sleep increases. This means that if you nap later in the day, you may not sleep very well or long at night. This is why your parents always tell you to not sleep so late or take a nap later in the day, because once you actually need to go to sleep that night, your body will not allow you to. Morning naps however are dominated by REM.

In this Ted Talk, I loved the visuals, as it was more of a cartoon-like presentation. The visuals helped you understand what she was saying more since she talked about a lot of biological aspects that play into naps. Most of the things she talked about I already knew because I am a psychology major, but for people who may know nothing about the parts of the brain, it really helps.