What Are the Physical Effects of Sleep Deprivation on the Human Body?

From Hormone Changes to Weight Gain, Major Problems May Result

Sleep deprivation is common for people in many societies, seemingly with no long-term damages, but is this true? Does sleep deprivation have lasting physical effects on the human body? What happens if you do not get enough sleep to meet your sleep needs? Learn about some of the consequences to your health, ranging from impacts on the nervous system affecting the brain and pain, vital sign changes affecting blood pressure, and hormone changes that impact weight gain and thyroid function.

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The Physical Effects of Sleep Deprivation

Sleep deprivation occurs any time that you get less sleep than your body needs. The degree of sleep deprivation can range from total acute sleep loss to chronic deprivation due to a reduction in the total sleep time. This can occur over one night or stretch over weeks, months, or even years. If someone requires 9 hours of sleep to feel rested, it is possible to become sleep deprived by getting 8 hours of sleep.

Most of the physical side effects from sleep deprivation are relatively minor and, thankfully, easily reversible. And the cure? Get some sleep. If you do not sleep enough, you may be faced with myriad consequences, including:

Neurologic Effects of Sleep Deprivation on the Brain and Pain

Sleep deprivation mimics the effects of drinking alcohol—you may experience slurred speech and uncontrolled reflexive movements of the eye called nystagmus.

You may also develop a slight shakiness or tremor in your hands. Some people even have a more pronounced droopiness in their eyelids, called ptosis.

Various other neurological reflexes can change in sleep deprivation. These are unlikely to causes symptoms you would notice. However, if your healthcare provider were to test them, you may have sluggish corneal reflexes, a hyperactive gag reflex, and hyperactive deep tendon reflexes.

In addition, you may have a reduced threshold for seizures. As a result, people with epilepsy are at greater risk for seizures when they are sleep deprived.

One thing that you may notice right away is an increased sensitivity to pain. Studies have shown our sensitivity to heat and pressure pain is especially enhanced when we don’t sleep enough. Also, there is reported to be an increased sensitivity to pain in our esophagus, as might occur in the setting of nighttime heartburn or gastroesophageal reflux disease (GERD). Over the long term, this may lead to a diagnosis of fibromyalgia or other chronic pain conditions.

Vital Sign Changes in Sleep Deprivation Affect Blood Pressure

Research studies have demonstrated that sleep deprivation may cause subtle changes in your vital signs. Vital signs are important physiological markers that are often tracked as part of a general health assessment. These include:

  • Body temperature
  • Blood pressure
  • Heart rate
  • Breathing rate

As an example, sleep deprivation may cause a small overall decrease in your body temperature. Changes in the other vital signs are relatively mild based on various studies. Seep-deprived people, when they do sleep, tend to have longer and more frequent pauses in their breathing called apnea.

Hormone Changes in Sleep Deprivation Impact Weight, Thyroid Function

Sleep deprivation can have significant and important effects on the secretion of hormones from endocrine glands, especially those that follow a circadian pattern. A classic example includes the effect of sleep loss or disruption in children and the impact on growth. Growth hormone is secreted during slow-wave sleep, which is more common in the early part of the night in children. When this sleep is disrupted, either through inadequate sleep or from disorders such as sleep apnea, the amount of growth hormone released is compromised. As a result, children may not reach their full growth potential, becoming shorter than they otherwise would have been.

Sleep deprivation also seems to affect the activity of the thyroid gland. It is thought that the increased energy needs while staying awake for too long demand more work from the thyroid.

Fortunately, studies also suggest that many other hormones (including sex hormones) do not seem to be affected by sleep deprivation, including:

  • Cortisol
  • Adrenaline
  • Catecholamine
  • Luteinizing Hormone
  • Follicle-Stimulating Hormone
  • Testosterone
  • Progesterone

This may provide you some relief, but there is still a risk of major health effects from not getting enough sleep.

Major Health Effects of Sleep Deprivation - Including Death

Ultimately, the concern of these various physical effects of sleep deprivation is the role it may have in our overall health. Indeed, sleep deprivation may negatively affect our health and may even lead to death in extreme situations.

Moreover, chronic sleep deprivation may adversely impact our metabolism, leading to impaired glucose tolerance (a risk for diabetes) and weight gain. In addition, there seems to be some evidence that sleep deprivation undermines our immune function, putting us at risk for frequent illness. There is also some concern that chronic sleep deprivation may contribute to conditions like cancer and even memory problems like dementia.

For all of these reasons, is it is important that we place a premium on our sleep and obtain the amount of rest that our bodies need.

A Word from Verywell

Ensure that you are meeting your sleep needs. The average adult needs 7 to 9 hours of sleep per night to feel rested. Older adults, beyond the age of 65, may only need 7 to 8 hours of sleep per night on average. Beyond the number of hours, quality is also important. Sleep apnea and other disorders can compromise sleep quality. Speak with a board-certified sleep physician about the need for testing. If you struggle with difficulty falling or staying asleep, such as occurs with insomnia, consider participation in a cognitive behavioral therapy for insomnia (CBTI) program that can help to alleviate the impacts of insomnia. Get the help that you need to ensure you avoid the physical effects of sleep deprivation.

Frequently Asked Questions

  • What is sleep deprivation?

    Sleep deprivation is when a person doesn't get enugh sleep to feel alert and well rested. It can be caused by stress, anxiety, sound or light sensitivity, sleep disorders, illnesses, and more. Sleep deprivation can have negative effects on the brain and body, which is why most adults are recommended to have between seven to nine hours of sleep each day.

  • What are the effects of sleep deprivation on the brain?

    The effects of sleep deprivation on the brain include irritability, depression, anxiety, poor concentration, forgetfulness, lack of energy, slowed reaction time, and many more.

  • Can sleep deprivation cause nausea?

    Yes. Perhaps surprisingly, sleep deprivation can contribute to gastrointestinal symptoms including nausea, vomiting, abdominal pain, gas, constipation, and diarrhea.

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4 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Medic G, Wille M, Hemels ME. Short- and long-term health consequences of sleep disruption. Nat Sci Sleep. 2017;9:151-161. doi:10.2147/NSS.S134864

  2. American Sleep Association (ASA). Sleep deprivation.

  3. American Sleep Association (ASA). Sleep deprivation effects on the brain.

  4. Centers for Disease Control and Prevention (CDC). Sleep deprivation.

Additional Reading
  • Kryger, MH et al. "Principles and Practice of Sleep Medicine." Elsevier, 5th edition, pp. 502-503.