Sleep deprivation is a health issue with which just about every college student is familiar. While students are most familiar with voluntary sleep deprivation, there are illnesses that lead to sleep deprivation. Insomnia and sleep apnea are two common causes of sleep deprivation. Insomnia may be caused by a disruption of neurotransmitter balances in the brain. The suprachiasmatic nucleus in the hypothalamus controls our circadian rhythms through the release of the hormone melatonin. When hormones are involved, any number of issues can arise. The suprachiasmatic nucleus itself could be damaged, there could be a tumor, the hormone receptors may not function properly, or it could be an entirely different issue. If the final effect is a disruption of melatonin’s function, it may lead to insomnia. There are many other possible causes of insomnia – it would take up a majority of this entry to list them all. Sleep apnea is more straightforward than insomnia. It occurs when the upper airway collapses when a person sleeps. This reduces airflow to the lungs and leads to restless sleep, among many other health complications if left untreated.
Regardless of whether a sleep-deprived individual has a medical issue or if he or she simply enjoys pulling all-nighters, the effects of sleep deprivation are extensive. There is no well-defined period of wakefulness after which one is considered “sleep-deprived,” but performance in certain tasks significantly decreases as a subject remains awake. Attention and working memory both suffer during extended periods of sleep deprivation. Studies also indicate that the frontal lobe, our region of decision-making and judgment, declines in function without sleep. It shows more activity, but its performance during tests does not improve from baseline, indicating sleep-deprived brains must work harder. Although memory was generally impaired, short term memory seems to improve during sleep deprived periods. This may have evolutionary advantages since, before the age of all night partying/studying, if the body was sleep deprived, it was likely due to a life-threatening event. Increasing the performance of short term memory would allow the individual to maintain his or her awareness of surroundings and of the situation. It could also just be a correlation that occurred during the study.
Sleep deprivation also affects growth and immune system function. Growth hormone is released mostly during sleep, thus an individual who does not sleep an adequate amount may grow less. Additionally, cortisol levels cycle through sleep and wakeful periods, with its concentration being the lowest during sleep. Cortisol is a hormone in the sympathetic autonomic pathway responsible for maintaining glucose levels in the blood and responding to stress over a long period of time. It suppresses the immune system and breaks down muscles and fats to help the liver generate glucose. The body interprets sleep loss as a stressful situation and responds through the sympathetic nervous system, increasing cortisol. Through this pathway, sleep deprivation can compromise the immune system and lead to increased vulnerability to diseases. Because our immune system is extremely important in protecting our bodies from cancers, there may be implications that long term sleep deprivation increases one’s risk to cancer.
Sometimes the occasional all-nighter is unavoidable, but there are health risks to repeating this practice. Everybody’s sleep needs are different; averages are around 7-8 hours. There are still multiple hypotheses as to why the human body needs sleep. They all agree, however, that we do need it. Studying sleep in humans is a difficult and complicated field, but it is certainly one of the most interesting and important current areas of research.