Sleep Deprived Teens On average, high school teenagers need nine to twelve hours of sleep for their bodies to function properly. The body goes through four stages of sleep. “Stage 1 sleep, the lightest phase, is the transition from wakefulness to deepest sleep. Stage 2, middle sleep, accounts for 40% to 50% of sleep time. Stages 3 and 4, called slow-wave or delta sleep, are the deepest levels and occur primarily in the first third of the night. Most high school students only reach the third or fourth level three times a night, which is the most important. At this stage the student's body is slowly repairing itself (Karriem-Norwood). These sleep-deprived findings caught the attention of Dr. Mary A. Carskadon of Brown University who conducted an experiment on the effects of sleep on the body, which revealed that students' bodies became accustomed to the circumstances in which they were involved. Denise Dador, a health specialist, said: “Experts say about 80% of high school students are sleep deprived. They are biologically programmed to stay up late” (Dador). Although the bodies of most high school students have evolved, side effects have emerged. Students have increased stress in their lives due to the pressure to finish homework; high blood pressure can also result from the same stress problem. Research has also found that a reduced amount of sleep in students causes decreased learning and memory, as their minds are focused on sleep. A high school freshman says, "If I sleep less than four hours I find it much more difficult to stay focused, which makes it difficult to pay attention in class and do well on homework," (qtd in Taylor) Dr. Kohler, a pediatric sleep expert, states that... in the center of the card... "eep Deprived" Center For Advanced Health. January 2010. Web. 1 April. 2014.Enayati, Amanda. “Does homework make your child sick?” CNN.com. March 21st. 2014. Web 1 April. 2014. “Excessive Homework and Sleep Deprivation” Teen Ink. March. 2011. Network. March 31. 2014. “Getting Enough Sleep Will Help You Raise Test Scores – AASM for Teens” MNT. January 8, 2008. Web. April 1. 2014.Karriem-Norwood, Varnada. WebMD “Common Sleep Disorders in Adolescents.” March 17, 2013. Web. April 1. 2014. “Benefits of Napping: 6 Reasons to Nap on National Napping Day” True Entertainment Magazine. March 12. 2013. Web. 1 April. 2014. “Featured Research on Homework” National Education Association. Nd Web. 1 April. 2014.Taylor, Hannah. “Sleep Deprivation and Its Effects on the Brain” Daily Emerald. October 28, 2013. Web. April 1. 2014.Weber, Trisha. “Connect” Evansville Business. May. 2012. Network. 1 April. 2014.