What are the benefits of sleep?
Nobody really knows why we sleep. The simplest answer is that sleep restores our body, restores our minds, and helps us think better. There are theories that nighttime dreams help us to consolidate our memories. There are other theories about how sleep electrically recharges the brain and restores brain chemicals to its proper levels.
What is the difference between being sleepy and tired?
If I got up and did a hundred jumping jacks, I might feel tired, but I wouldn't feel sleepy. Sleepiness is a feeling of lack of sleep, obviously, and tiredness is a feeling of physical fatigue.
Does everyone have the same sleep requirements?
No. It varies, not only in the amount of sleep, but the timing of sleep. There are true night owls and true morning larks. Some people are genetically inclined to be morning people and others seem to be set up to be night people. There are short sleepers and long sleepers. Some require more sleep than average and some seem to require less than average to feel refreshed and energized.
Do we need more or less sleep as we age?
You should never need more sleep as you age. If, in your youth, you thought you performed well at seven hours of sleep, you should not need 7 1/2 or eight as an older adult. If you find that your sleep demand increases, then you are probably compensating for a decreased quality of sleep. And when we think about sleep, it's important to think not just about the amount of sleep, but the quality as well.