Different parts of the brain aren't always in the same stage of sleep at the same time, notes neurologist and author Guy Leschziner. When this happens, an individual might order a pizza or go out for a drive — while technically still being fast asleep.
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A CPAP machine can treat obstructive sleep apnea, a disorder which causes people to temporarily stop breathing throughout the night. But the machines, which blow air into a person's airways, take some getting used to.
Rough night? Depending on specific tweaks to their genes, some fruit flies have trouble falling asleep, and others can't stay asleep. Getting too little shut-eye hurts their memory.
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