Somnolence (or “drowsiness “) is a
state of near-sleep, a strong
desire for sleep, or sleeping for unusually long periods (cf.
Sleepiness can be dangerous when performing tasks that require
constant concentration, such as driving a vehicle. When a person is
sufficiently fatigued , microsleeps may be experienced.
The human body can become sleepy in response to infection.
Such somnolence is one of several sickness behaviors or reactions
to infection that some theorize evolved due to promoting recovery
by conserving energy while the body fights the infection using fever
and other means.