Inadequate sleep—such as not sleeping long enough overall or having poor quality sleep—affects both how we feel and how we function.
Short-term effects can include drowsiness or sleepiness, irritability, reduced alertness, poor motor skills, and attention problems.
Inadequate sleep over a longer period of time can affect how the body functions. For example:
- NIH research shows that not getting enough sleep is associated with excess body weight and obesity.1 All age groups, including children, seem to be affected in the same way.2 In addition, blood samples from people who get little sleep show metabolic changes that are similar to those seen in obese people.3
- Sleep duration is associated with type 2 diabetes. A review of 10 studies involving more than 18,000 people found that people who got between 7 and 8 hours of sleep per day have the lowest risk of diabetes. Those who sleep more or less than that 7 to 8 hours have a higher risk of having diabetes.4
- Sleep apnea, a condition in which a person temporarily stops breathing while sleeping, increases risk for several different cardiovascular conditions, including high blood pressure (hypertension), stroke, coronary heart disease, and irregular heartbeat.5
- Research has also found that inadequate sleep increases blood pressure levels in people who already have hypertension. This finding may be one reason why people who lack sleep over time have an increased risk of cardiovascular disease.6
- Inadequate sleep, especially over a long period of time, can lead or contribute to 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 In extreme cases, sleep deprivation is also linked to psychosis, paranoia, and hallucinations. Disrupted sleep can also trigger manic episodes, including agitation and hyperactivity, in people with bipolar disorder,8 a mood disorder in which people may cycle between extreme highs and extreme lows in their mood.
- Sleep disturbance has been linked to pain and disability. For example, in a recent NIH-supported study of arthritis patients, sleep disturbance was associated with pain and depression and predicted disability.9 In another study of arthritis patients with knee or hip replacement, researchers found that pain was associated with disturbed sleep but also that disturbed sleep was linked specifically to pain symptoms.10