FALCONIUM

With schedules teeming with AP classes and extracurricular activities—not to mention distractions such as the Internet, television, and video games—, many high school students find it difficult to set aside time for a good night’s rest. Students increasingly remain awake till the wee hours of the morning, sometimes even staying up all night for the sake of completing class assignments. Unfortunately, sacrificing sleep results in serious consequences. Although the amount of sleep needed declines as a person transitions from childhood to adolescence to adulthood, recent studies have shown that adolescents still need an average of 9.2 hours of sleep per night for optimal performance. However, only 15% of high school students sleep 8.5 hours or more, according to a 1998 study by Wolfson and Carskadon. Interestingly, teenagers undergo a “phase shift” during puberty that causes them to sleep later than preadolescent children, despite their need for more sleep.

The effects of sleep deprivation vary from person to person: one person may breeze through the day on 5 hours of sleep while another will struggle onward like a zombie. This variation may be partially genetic. Results from differences in length in the PERIOD3 (PER3) gene indicate that people with the long form of the PERIOD3 gene feel the effects of sleep deprivation quickly, while those with the short form possess short-term resilience. The gene may differentially influence the effects of sleep deprivation on function in the early morning. Symptoms of sleep deprivation generally include reduced concentration, inefficiency in learning, poor memory capacity, headaches, dizziness, irritability, growth impairment, depression, high blood pressure, and microsleeps (involuntary sleep lasting for 10-60 seconds).

Unlike muscles, which can be regenerated while a person is conscious and resting, neurons can only regenerate in the cerebral cortex and form new synaptic connections during sleep. Thus, reduced sleep can result in malfunctioning neurons, which cause dramatic changes in behavior. Lack of sleep negatively affects language processing. Studies have been conducted in which magnetic resonance imaging scans compared brain functions of sleep-deprived subjects and well-rested subjects based on results from verbal tests. In well-rested subjects, the temporal lobe of the brain (which controls language processing) was very active, whereas in the sleep-deprived subjects, it was inactive. However, the parietal lobe, which controls cognition and sensory perception of the world, was activated in sleep-deprived subjects and allowed them to complete the verbal test relatively well, though their performances were poor in comparison to those of their well-rested counterparts.

Sleep deprivation also leads to an increased risk for diseases such as cancer, heart disease, diabetes, and obesity likely due to its profound effect on many vital hormones in the body. One consequence of sleep deprivation is impeded growth because growth hormone is secreted during deep sleep. People spend less time in the stages of deep sleep as they age, explaining why adults gradually stop growing. If adolescents are deprived of sleep, their growth is impaired while their fat-gaining process is sped up, potentially leading to obesity. Sleep deprivation also results in reduced production of the hormone leptin, which notifies the body when it is full. An insufficient amount of it causes a person to desire more food. The amount of food consumed may be sufficient, but without the bloated feeling from leptin, the body will still feel hungry. In fact, a survey of high school students in Ohio revealed that students that slept for less than 5 hours each night were 8 times more likely to be overweight than those that slept for over 8 hours. A second study conducted by Arlet V. Nedeltcheva et al revealed that insufficient sleep also makes it harder to lose weight because it affects a hormone called ghrelin, which can cause increased appetite and fat retention.

Finally, sleep deprivation affects melatonin release. The hormone melatonin acts as an anti-cancer agent and can prevent tumor growth. It is released at night in the dark, so exposure to light late at night can decrease melatonin levels and increase a person’s risk of developing cancer. Sleep deprivation also depletes neurotransmitters—chemical messengers in the brain associated with mood regulation, leading to vulnerability to depression and abnormal levels of irritability.

Recent research has demonstrated that sleep deprivation has detrimental consequences, but there is also hope for reversing its effects. Robert Havekes and his colleagues have discovered that the enzyme phosphodiesterase 4D, known as PDE4, contributes to the effects of sleep deprivation. The hippocampus, an area of the brain that consolidates new memories, requires a cell-signaller called cAMP, which is required for many biochemical processes throughout the body including the regulation of hormones. In a study of sleep-deprived mice, Havekes and his colleagues found that sleep deprivation resulted in an increased amount of PDE4 activity and a decreased amount of cAMP. By inhibiting PDE4 activity, they were able to counteract the consequences of sleep deprivation.

Although future research will undoubtedly generate new methods to counter the results of sleep deprivation, the best remedy for sleep deprivation is still a good night’s sleep.

By Sarah Watanaskul

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