The difference between the amount of sleep attained and the amount needed to maintain alert wakefulness during the daytime, when the amount attained is less than the amount needed, is known as

Sleep debt

Explanation:

Sleep debt is the name given to the difference between the amount of sleep the human body needs to rest and the amount of sleep individuals can get from day to day commitments. It can also be defined as the difference between the amount of sleep achieved and the amount needed to keep vigil alert during the day when the amount reached is less than the amount needed.

Decreased sleep for various reasons creates a kind of debt to the body that can hardly be paid. This debt alters the body by weakening the immune system, inducing the person to have diabetes, morbid obesity, heart disease, memory impairment, poor concentration, vision problems, and sleep that never goes away.  Such manifestations resulting from sleep debt may occur in the short and long term, depending on the individual's rhythm of life and the debt they have with the body. As this debt increases, so do the signals.

Sleep debt

Explanation:

The difference between the amount of sleep attained and the amount needed to maintain alert wakefulness during the daytime, when the amount attained is less than the amount needed, is known as sleep debt.