Sleepiness is that heavy, drowsy feeling when your body and brain want to sleep. Your eyelids feel weighted down, your thoughts get fuzzy, and you might yawn over and over. When you're sleepy, it's hard to concentrate on homework or follow what your teacher is saying because your mind keeps drifting.

Sleepiness usually means your body needs rest. After a long day of school, sports practice, and playing with friends, sleepiness is your body's way of saying it's time to recharge. Most kids need about 9 to 11 hours of sleep each night, so feeling sleepy around bedtime is normal and healthy.

But sleepiness at the wrong time, like mid-morning at school, can signal you didn't get enough sleep the night before. Some people feel sudden waves of sleepiness after eating a big lunch. Others get sleepy when they're bored, though that's different from true physical tiredness.

Fighting sleepiness when you really need sleep makes everything harder. Your memory doesn't work as well, you make more mistakes, and you might feel grumpy. When you're genuinely sleepy, the best solution is usually simple: get some sleep.