Insomnia is the inability to get the amount of sleep you need to wake up feeling rested and refreshed. Because different people need different amounts of sleep, insomnia is defined by the quality of your sleep and how you feel after sleeping—not the number of hours you sleep or how quickly you doze off. Even if you’re spending eight hours a night in bed, if you feel drowsy and fatigued during the day, you may be experiencing insomnia.
Insomnia or sleeplessness is a sleep disorder in which there is an inability to fall asleep or to stay asleep as long as desired, that is characterized by difficulty falling and staying asleep. Insomnia also varies in how long it lasts and how often it occurs.