Problem sleepiness is a condition that is due the all the natural sleeping and awaking cycle that the body has, along with inadequate sleeping, certain medications, and even sleeping disorders. 

There are two different periods in a day that a body experiences sleepiness. During these periods of time a person is at an increasing risk of falling asleep. Especially a person that has not gotten enough sleep the night before. 

Every individual varies on the amount of sleep that in needed per night. Everyone needs a certain amount of rest to be able to function the next day. The average person gets 8 to 8.5 hours per night. However, some individuals need to have more sleep than those hours to try to be able to avoid sleepiness. 

Sleeping disorders are also another common problem with sleepiness. Some sleep disorders that relate to the issue could be restless leg syndrome, sleep apnea, insomnia, and narcolepsy. 

Not only do certain medical issues relate to problem sleepiness but certain prescribed medications can play a role in the problem sleepiness that you might be experiencing. So be sure and consult with you physician.