Why do we need sleep?
Short Answer
We need sleep to restore brain and body function. It stabilizes memory and learning, regulates hormones and immunity, supports cellular repair, and keeps attention and mood networks functioning well.
Why This Matters
Sleep matters because the brain uses it to rebalance synapses, consolidate memories, and clear metabolic byproducts, which leads to sharper thinking and steadier mood. It also regulates stress hormones and immune signaling, so poor sleep results in higher inflammation and worse resilience. Over time, consistent sleep leads to better performance, recovery, and long-term health.
Where This Changes
Needs vary by age, genetics, and health, so “enough” is partly individual. Short sleep can be tolerable occasionally, but chronic restriction accumulates and can take days to normalize, and sleep disorders can leave you impaired even with long time in bed.