“It turns out that about 3 per cent of the human population need on average two hours' less sleep a night than the rest of us. Let's call them the super-awake. And another 3 per cent of the population are the super-sleepers, who need an extra two hours' sleep to function normally. And the average person? We need about seven to nine hours a night to be at our superhero best.” SleepAverage PersonSleep RequirementsVariation In Human Population Book:On Sleep Source: On Sleep