Why Do Short Sleep and Poor Sleep Both Leave You Impaired?

On Huberman Lab, four hours of sleep leave you impaired the next day even when the quality is brilliant, and eight hours of sleep leave you impaired when the quality is very poor. Quantity and quality both have to be present for a beneficial next day. One without the other fails.

Waking up and spending some time awake is normal and natural. The concern begins when you are consciously aware of waking six, seven, or eight times through the night, so sleep is fragmented, or when an awake stretch runs upwards of 25 minutes. Sleep science in the past five or ten years has established that quantity is important and quality is just as important.

Infrequent, short waking does not call for alarm. Frequent waking all through the night, or long stretches upwards of 25 minutes, is the point to look into the pattern.