How Does Lack of Sleep Affect You?

Withholding sleep has been used as a torture or interrogation technique in the past, so you know that sleep serves some essential purpose, especially when you don't get your eight hours a night. The majority of Americans do not get enough sleep, with 56 percent complaining that they become drowsy at times during the day. College students should get at least eight hours of sleep -- younger children may need more -- while the older people need less. No one is quite sure what happens during sleep; the brain may process learning or incorporate memories, the immune system can diagnose and repair injuries and active muscles may rest.

Cognitive Ability

• The parietal lobe of the brain processes mathematical tasks.

  J. Christian Gillin, a psychiatrist and researcher from the University of California at San Diego, found that subjects deprived of sleep performed poorly on mathematical tests. The parietal lobes -- the centers of the brain that perform mathematical functions -- showed less activity than in subjects given normal amounts of sleep.

  Children in their adolescent years need a little more than nine hours of sleep a night. At this age, children's brains are growing and changing at a phenomenal rate, and sleep allows children to accommodate and incorporate those changes. Besides the physical feelings of drowsiness and fatigue, children who lack sleep cannot think abstractly. Additionally, students who consistently receive higher grades report that they get more sleep than students receiving lower marks.

Obesity

• Sleep deprivation may lead to a future of unhealthy weight gain.

  Dr. S. R. Patel and colleagues from Case Western Reserve University's Department of Medicine found that different studies published between 1966 and 2007 pointed to sleep-deprived children either having weight issues or becoming obese in the future. Seventeen of 21 studies indicated that adults who received less sleep than normal showed greater incidences of becoming obese later in life. With older adults, the correlation between lack of sleep and weight gain was not as significant.

Diseases

• Higher incidences of diabetes have been associated with insufficient sleep.

  Sleep affects the body's response to disease: The immune system fights off infection while people doze. People who consistently reported insufficient sleep had higher incidences of high blood pressure, heart disease and diabetes. Fatal Familial Insomnia, an incurable disease transferred in the genes, destroys brain cells and causes sleeping difficulties, hallucinations and increased heart rates.

Mental Disorders

• With loss of sleep, people become restless, think irrationally and exhibit signs of depression. Dr. Matthew Walker, a researcher with the Sleep and Neuroimaging Center at the University of California at Berkeley, authored a study with colleagues to determine the correlation between loss of sleep and erratic emotions. The researchers allowed subjects who had no sleep for 35 hours to view negative scenes, such as those depicting gory deaths. They then found that these images caused subjects to react excessively to the image by triggering a primitive part of the brain activated in stressful situations. In subjects receiving normal sleep, the brain linked to the prefrontal cortex, a center of the brain tasked with keeping emotional responses under control.

Physical Performance

• Many jobs require employees to be fully alert while on duty, and any lapse in alertness may lead to devastating consequences for others. Investigators attribute a portion of the blame from the Three-Mile-Island nuclear disaster, the space shuttle Challenger explosion and the Exxon Valdez oil spill to technicians who had less sleep than normal. Charles Czeisler, a researcher with Harvard Medical School's Division of Sleep Medicine, found that if hospitals limited doctors to working 16-hour shifts and 80 hours a week, 36 percent of medical errors could be eliminated.