Sleep Debt You Can’t Feel

Think you’re one of those people who can "adapt" to just five hours of sleep?

The science suggests you might just be losing the ability to judge your own impairment.

Early studies once suggested humans could adapt to chronic sleep loss, but modern,

well-controlled research has debunked that. It turns out that while your actual

cognitive performance—things like memory and reaction time—continues to decline, your subjective

feeling of sleepiness actually levels off. Essentially, you underestimate

how much you're struggling. In driving simulators, sleep-deprived subjects were found to be

completely unable to accurately recognize their own crash risk. You might feel "recovered,"