Beyond its short-term effects, inadequate sleep affects overall health in a number of ways. Diabetes, cardiovascular disease, hypertension, obesity, and depression have all been linked to inadequate sleep.
Clinical research funded by the NIH shows that a short duration of sleep is associated with excess body weight.1, 2 All age groups, including children, seem to be affected in the same manner.3 In addition, analysis of blood samples from people with inadequate sleep has shown metabolic changes that are similar to those seen in obese people.4 Researchers think that inadequate sleep could lead to changes in the brain's hypothalamus, which regulates appetite and energy expenditure. These changes in the brain may explain how inadequate sleep contributes to weight gain.3
Insufficient sleep has been associated with the development of type 2 diabetes. A study funded by the NIH, for example, reported that the duration and quality of sleep can predict a person's levels of hemoglobin A1c, which health care providers measure to monitor blood sugar levels.5
Sleep apnea, a condition in which a person temporarily stops breathing while sleeping, causes an increase in a person's risk for several different cardiovascular conditions, including hypertension, stroke, coronary heart disease, and irregular heartbeat.6
Research has found that having even one night of inadequate sleep further increases blood pressure levels in people who already have hypertension. This finding may be one of the factors explaining the increased risk of cardiovascular disease in people who sleep too little.7
While a single night of inadequate sleep can make you irritable and moody, chronically insufficient sleep can lead to long-term mood disorders. Chronic sleep problems have been linked to depression, anxiety, and mental distress. For example, one study reported that participants who slept only 4.5 hours per night were more stressed, sad, angry, and mentally exhausted than a comparison group with longer sleep.7
Extreme sleep deprivation can lead to a psychotic state of mind, with paranoia and hallucinations experienced by people who otherwise seem healthy. In addition, disrupted sleep can trigger manic episodes, including agitation and hyperactivity, in people with manic depression.8 Manic depression is a mood disorder in which people experience cycles of extreme highs and extreme lows in their mood.
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