Sleep is a normal, easily reversible, recurrent, and spontaneous state of less efficient responsiveness to external stimulation. Sleep usually requires the presence of flaccid or relaxed skeletal muscles, and the absence of the overt, goal directed behavior of which the waking organism is capable. How much sleep does a person need?
For adults, anything between 6, [...]

If you are having trouble sleeping, you are not alone. This increases with age, and affects about 40 percent of women and 30 percent of men. Primary insomnia is not related to other health conditions, and is brought on either by a traumatic event related to sleeping, or by increased physical or psychological arousal at [...]