Teenagers require more sleep, by 1 to 2 hours, than do their younger 9 and 10 year old siblings, yet most teenagers get 1 to 2 hours less. Teenagers are the sleepiest members of society and this sleepiness is associated with poor school performance, increased drug and alcohol use, and increased automobile accidents. This level of sleepiness may also play a role in the high rate of teenage suicides. However, in addition to requiring more sleep than do 9 and 10 year old children, or adults, teenagers typically have altered biologic rhythms which vary the time of night teenagers sleep best and the times of day teenagers are most alert. The timing of sleep and wake is very dependent on the sun.
Humans typically sleep at night and are awake in the daytime.
The cells of the biologic clock act independently of when we are awake and when we are asleep but are very responsive to bright light. Everyone has experienced difficulty sleeping during the day after having been awake all night. Everyone has experienced difficulty staying awake all night, for instance. Most sleep specialists feel that it is the biology of the brain that requires sleep. Thus, as a person is awake all day, that person develops a need for sleep.