Why Do We Sleep and How Can We Sleep Better?
From The Observatory
We spend about a third of our lives sleeping, yet its purpose remains unclear. Sleep is essential for brain and body functions, but scientists have not agreed on a single explanation for why we sleep. Several theories provide insight, focusing on energy conservation, restoration, memory consolidation, and brain health.
The energy conservation theory suggests that sleep lowers metabolic rates, saving energy when hunting or gathering food was impractical for our ancestors. However, sleep also made them vulnerable to predators. The restorative theory claims sleep supports bodily repairs like tissue growth and hormone release. Some researchers argue it allows the brain to clear toxins, but a recent study challenges this claim.
The brain plasticity theory links sleep to the brain’s ability to adapt, remove waste, and reorganize neurons, which is critical for learning and development. This theory emphasizes sleep’s role in memory consolidation, where important memories are stored while irrelevant ones are discarded.
Another perspective, the synaptic homeostasis theory, describes sleep as a nightly “decluttering.” Synapses, which transmit signals in the brain, are pruned during sleep to prevent overload. A 2024 study found that high-frequency brain waves, called sharp wave ripples, prioritize and replay significant memories during sleep, aiding learning and memory retention.
Sleep also impacts emotional well-being, as it regulates stress and enhances decision-making. The amygdala, striatum, and insula—brain regions tied to emotion and self-awareness—are highly active during sleep. Additionally, sleep affects hunger hormones, supporting weight management, and boosts the immune system by producing proteins that fight infection.
Finally, sleep may protect against cognitive decline. Research links poor sleep to an increase in brain plaques associated with Alzheimer’s disease. Overall, while the exact purpose of sleep remains a mystery, its benefits are undeniable for both body and mind.
🔭 This summary was human-edited with AI-assist.
