A list of health effects linked to poor sleep or lack of sleep which keeps growing with each passing year. For example, poor or insufficient sleep has been linked to:

  • Impaired memory and reduced ability to learn new things — Due to your hippocampus shutting down, you will experience a 40% deficit in your brain with respect to its ability to make new memories when you’re sleep deprived.
  • Reduced ability to perform tasks, resulting in reduced productivity at work and poor grades in school.
  • Reduced athletic performance.
  • Reduced creativity at work or in other activities.
  • Slowed reaction time, increasing your risk of accidents on the road and at work — Getting less than six hours of sleep leaves you cognitively impaired. In 2013, drowsy drivers caused 72,000 car accidents in which 800 Americans were killed and 44,000 were injured. 
  • Even a single night of sleeping only four to six hours can impact your ability to think clearly the next day.
  • Increased risk of neurological problems, ranging from depression to dementia and Alzheimer’s disease — Your blood-brain barrier becomes more permeable with age, allowing more toxins to enter. This, in conjunction with reduced efficiency of the lymphatic system due to lack of sleep, allows for more rapid damage to occur in your brain and this deterioration is thought to play a significant role in the development of Alzheimer’s.
  • Increased risk of Type 2 diabetes — In one study, “excessive daytime sleepiness” increased the risk of Type 2 diabetes by 56%.
  • Weakened immune function — Research suggests deep sleep strengthens immunological memories of previously encountered pathogens. In this way, your immune system is able to mount a much faster and more effective response when an antigen is encountered a second time.
  • Increased risk of obesity — By causing a prediabetic state, lack of sleep increases feelings of hunger, even if you’ve already eaten, which can wreak havoc on your weight.
  • Increased risk of cancer — Tumours grow two to three times faster in laboratory animals with severe sleep dysfunctions. The primary mechanism thought to be responsible for this effect is disrupted melatonin production, a hormone with both antioxidant and anticancer activity.
  • Increased risk of high blood pressure, heart attacks and cardiovascular disease – Japanese research showing male workers who average six hours of sleep per night or less are 400 to 500 percent more likely to suffer one or more cardiac arrests than those getting more than six hours of sleep each night. Other research has demonstrated that women who get less than four hours of shut-eye per night double their risk of dying from heart disease. In another study, adults who slept less than five hours a night had 50 percent more coronary calcium, a sign of oncoming heart disease, than those who regularly got seven hours.
  • Increased risk of osteoporosis.
  • Increased risk of pain and pain-related conditions such as fibromyalgia — In one study, poor or insufficient sleep was the strongest predictor for pain in adults over 50.
  • Increased susceptibility to stomach ulcers.
  • Impaired sexual function.
  • Impaired regulation of emotions and emotional perception — Your amygdala, one of your brain’s centerpiece regions for generating strong emotional reactions, including negative ones, becomes about 60 percent more reactive than usual when you’ve slept poorly or insufficiently, resulting in increased emotional intensity and volatility.
  • Increased risk of depression and anxiety (including post-traumatic stress disorder), schizophrenia and suicide — In fact, sleep problems are defining factors in diagnosing psychiatric disorders.
  • Premature aging by interfering with growth hormone production, normally released by your pituitary gland during deep sleep.
  • Increased risk of dying from any cause — Sleep deprivation prematurely ages you by interfering with your growth hormone production, normally released by your pituitary gland during deep sleep. Compared to people without insomnia, the adjusted hazard ratio for all-cause mortality among those with chronic insomnia was 300 percent higher.