There are few things that are as beneficial for your memory as having a good night’s sleep. Let’s understand why.

If you’re tired, it’s hard to pay attention, and memory requires attention

To remember information, you need to pay attention to it. If you’re tired, you simply cannot pay attention as effectively as you would if you were well rested. That statement seems straightforward, but it brings up another question: Why do you get tired?

You may feel tired and have trouble paying attention either because you’ve been awake too many hours and sleep pressure is building up, or — even if you’ve had a nap — because it is the middle of the night and your circadian rhythm (your internal clock) is telling you to sleep. In either case, you’ll you have trouble paying attention, and thus trouble remembering.

Does caffeine help?

Caffeine blocks chemical receptors in your brain so that, temporarily, you cannot feel the sleep pressure. Thus, caffeine can enable you to be more alert, be more attentive, and remember better. But as you probably know from your own experience, caffeine can only delay the mounting sleep pressure, which eventually leads to overwhelming tiredness.

Get ready for new learning

When you learn new information during the day, it is temporarily stored in the hippocampus, a seahorse-shaped part of your brain behind your eyes. The hippocampus has a limited storage capacity. If you exceed it, you may have difficulty adding new information — or you may actually overwrite an old memory with a newer one.

Fortunately, that doesn’t usually happen. Each night while you sleep, the connections between neurons (called synapses) shrink to reduce or eliminate the memories you don’t need — such as what you ate for breakfast last week and the clothes you wore yesterday. This selective pruning of synapses during the night prepares you to form new memories the next day.

Sleep to consolidate memories

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