How does inadequate sleep affect health?

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

Cardiovascular disease

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

High blood pressure

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

Mood disorders

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.

  1. Taheri, S., Lin, L., Austin, D., Young, T., & Mignot, E. (2004). Short sleep duration is associated with reduced leptin, elevated ghrelin, and increased body mass index. PLoS Medicine, 1(3), 210-217.
  2. Gangwisch, J. E., Malaspina, D., Boden-Albala, B., & Heymsfield, S. B. (2005). Inadequate sleep as a risk factor for obesity: Analyses of the NHANES I. Sleep, 28, 1289-1296.
  3. Taheri, S. (2006). The link between short sleep duration and obesity: We should recommend more sleep to prevent obesity. Archives of Disease in Childhood, 91, 881-884.
  4. Spiegel, K., Knutson, K., Leproult, R., Tasali, E., & Van Cauter, E. (2005). Sleep loss: A novel risk factor for insulin resistance and type 2 diabetes. Journal of Applied Physiology, 99, 2008-2019.
  5. Knutson, K. L., Ryden, A. M., Mander, V. A., & Van Cauter, E. (2006). Role of sleep duration and quality in the risk and severity of type 2 diabetes mellitus. Archives of Internal Medicine, 166, 1768-1764.
  6. Kasasbeh, E., Chi, D. S., & Krishnaswamy, G. (2006). Inflammatory aspects of sleep apnea and their cardiovascular consequences. Southern Medical Journal, 99, 58-67.
  7. Division of Sleep Medicine at Harvard Medical School. (2007). Sleep and disease risk. Retrieved May 29, 2012, from External Web Site Policy
  8. National Institute of Neurological Disorders and Stroke. (2007). Sleep and disease In Brain basics:  Understanding sleep. Retrieved May 29, 2012, from