Health Effects of Poor Sleep - Quantity and Quality

Sleep is an essential physiologic process concerned with maintaining many bodily functions and systems. Lack of sleep can produce a number of serious side effects affecting every area of human health. These include errors of judgment, which may kill or maim many people. Other consequences include increased morbidity and mortality, poor performance, increased risk of accidents and injuries, reduced level of functioning, and poorer quality of life. Family life suffers, and many more healthcare visits become necessary.

Immediate consequences include driving accidents which cause over 2000 fatal crashes and 40,000 non-fatal injuries each year in the US. Delayed sequelae include the metabolic disorders, such as hypertension, diabetes, obesity, depression, cardiovascular disease, and even cancers.

Central nervous system deficits

Impairment of long- and short-term memory, poor concentration and difficulty in assimilating new things, poor judgment and decreased creativity, and labile emotions, are some serious effects brought about by sleep deprivation. Motor function is reduced, as is the attention span, while the reaction time actually goes up in proportion to the sleep deprivation, leading to poor hand-eye coordination similar to that of a person with a blood alcohol concentration of 0.1%.

In persons with bipolar disorder, mania is often precipitated by sleeplessness. Studies of people who were allowed only a little sleep every night found that their levels of stress, anger, sadness, and mental fatigue went up significantly. Hallucinations, depression, impulsive behavior, and suicidal thoughts may be prompted by lack of sleep. Microsleeps, lasting for a few seconds in most cases, which occur without the person knowing it, have been incriminated in many driving and other machinery-related accidents.


Lack of sleep can cause the immune system to produce less antibodies and T-lymphocytes, and thus the body becomes more prone to infection and has reduced capability to fight illness. Insomniacs are at higher risk of colds and influenza. One study on mice has also found that sleep disruption on a regular basis leads to faster tumor growth than when normal sleep is allowed. Rodents who were absolutely deprived of sleep died of fatal infections in a remarkably short time.

Chronic illnesses

Chronic illnesses such as obesity, heart disease, and diabetes are more likely to occur in individuals with long-term insomnia. Sleep deprivation is associated with higher cortisol and ghrelin levels, and lowered leptin levels. Since ghrelin makes for increased hunger, and leptin has the opposite effects, lack of sleep on a frequent or long-term basis can produce weight gain and obesity.

Insulin levels increase following sleeplessness, which can cause type 2 diabetes. Again, lack of sleep elevates the blood pressure for more than 24 hours.

Since insomnia is associated with higher levels of pro-inflammatory chemicals, the odds of cardiovascular disease also go up.

The risk of depression and anxiety is increased when individuals sleep less than 6 hours a night.

Cancer risk is also higher in sleep-deprived individuals. Mortality rates are higher, and overall quality of life is reduced.


Sleep deprivation causes disruption of the reproductive hormones and hence prevents ovulation from occurring properly, which can result in infertility. In addition, libido is also lower in individuals with less sleep.


Loss of productivity is associated with not getting enough sleep, which may be below 10 hours a day for children, 9-10 hours for adolescents, and 7-8 hours for adults. However, a third of adults get 6 hours or less of sleep, while a third of adolescents get only 8 hours or less of sleep a night on average.

Academic problems

Children with sleep problems are more mischievous and less focused at school. Concentration is affected, the risk of attention-deficit hyperactivity disorder is increased, while impulsive and risk-taking behavior becomes more common.

What would happen if you didn’t sleep? - Claudia Aguirre



Further Reading

Last Updated: Feb 27, 2019

Dr. Liji Thomas

Written by

Dr. Liji Thomas

Dr. Liji Thomas is an OB-GYN, who graduated from the Government Medical College, University of Calicut, Kerala, in 2001. Liji practiced as a full-time consultant in obstetrics/gynecology in a private hospital for a few years following her graduation. She has counseled hundreds of patients facing issues from pregnancy-related problems and infertility, and has been in charge of over 2,000 deliveries, striving always to achieve a normal delivery rather than operative.


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  1. Maryam Yousaf Maryam Yousaf Islamic Republic of Pakistan says:

    This article is very informatic after read this article I am able to know about Health Effects of Poor Sleep especially "Infertility" this is very common in working women because they suffering from lack of sleep.

The opinions expressed here are the views of the writer and do not necessarily reflect the views and opinions of News Medical.
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