why people feel sleepy during boring classes

Sleeping is a process which requires a human being to takes rest, to rest his muscles, decrease its energy and increase his storage reserves. Sleeping allows people to learn and memorize things properly and helps to retain things in mind. That is why it is said that one should have proper sleep before exam times.

Sleeping is caused by Ventrolateral Per optic Nucleus region. It is a complex {VLPO} which is in the hypothalamus region. It is a complex hormonal mechanism. When a person needs to sleep the VLPO become active and inhibits the neurotransmitters GABA to initiate sleep. There is also a normal sleep-wake cycle in our body called circadian rhythm which helps to maintain body temperature and secretion of the hormone.

Human beings are able to stay awake and alert because the mechanism which is called Ascending Reticular Activating System{ARAS} which collects inputs from all sensory organs and helps to stay awake.

When we sleep the signals which are sent by ARAS is switched off and the person goes to sleep. It is switched off so that the person sleeping becomes unaware of the external actions. This is what happens in boring classrooms. When boring classes are going on the student himself withdraws from external actions and goes to sleep which reduces sensory inputs and activates sleep centres.

There may be other reasons for a student to sleep in the class. They may have slept less in the previous day. Adolescents should sleep 8.5 hours to 9.25 hours.