An average adult needs at least 7 hours of sleep in order to be fully functional. Short-term sleep deprivation results in tiredness, moodiness, loss of memory and a lower quality of life. However, chronic sleep deprivation can result in more serious health consequences, including heart problems, high blood pressure, diabetes, obesity and depression.
What is happening while we sleep? Here, we describe how sleep is restorative and what happens when we are not getting enough sleep.
Central nervous system
Your brain and spinal cord make up the central nervous system, which acts as a highway of communication in order to coordinate activities of all parts of the body. Sleep is necessary to keep the central nervous system functioning properly. During sleep, the neurons in your brain form pathways that help you process new information you learned during the day. Sleep deprivation interrupts these pathways, leaving you with memory problems and difficulty in learning new things. The brain also loses its ability to fully coordinate with the body, which increases risk for accidents. You may also become slow at processing information and responding to urgent situations. Research has shown that sleep deprivation is akin to over-drinking when it comes to its effects on the brain.
Sleep deprivation also negatively affects your emotional state, leaving you feeling cranky and impatient. Other risks include anxiety, paranoia, impulsive behavior, or depression. Unfortunately the relationship between sleep and mental health is a two-way street. Sleep problems are particularly common in people diagnosed with anxiety, depression, bipolar disorder, and attention deficit hyperactivity disorder. Seeking professional help for treatment strategies for mental health disorders may help alleviate problems with sleep.
There is an old wive’s tale that if you don’t sleep well, you will get sick. There is some truth to that folklore! During sleep, your immune system produces protective and infection-fighting proteins that protect your body against illnesses. Some even promote sleep. When you don’t get enough sleep, the production of these protective proteins are also blunted, so you are no longer as capable in fighting off infections. A lack of sleep even makes the flu vaccine less effective by reducing your body’s ability to respond. Long-term sleep deprivation increases your risk for chronic inflammatory conditions such as autoimmune disorders, inflammatory bowel disorders and cardiovascular diseases.
Sleep is critical for lung health and function. During sleep, breathing patterns change, becoming less regular and shallow. People with respiratory problems may have difficulty breathing at night, which affects their sleep quality. Poor sleep quality in turn worsens pre-existing respiratory problems. In fact, people who have respiratory problems are often evaluated in a sleep study by their pulmonologists.
Obstructive sleep apnea, a nighttime breathing disorder that affects 20 million American adults, causes periodical pauses in breathing during sleep. Some pauses can last for up to 10 seconds and may occur hundreds of times per night. These disruptions in breathing greatly lower sleep quality. With such sleep interruptions, people with severe obstructive sleep apnea face greater risks for heart attacks, stroke, coronary artery disease, and heart failure.
Sleep gives your digestive system a chance to rest. During the day, your digestive system is constantly working to break down food. During sleep, your metabolism and digestive system slows down, allowing your digestive system to recover from a day's work. Sleep deprivation puts your body in a pro-inflammatory state, which may worsen symptoms of inflammatory bowel disorders. A lack of sleep may also impact your gut microbiome, which in turn influences your gut health, trigger inflammation, and also alter the way your body handles blood sugar. A nutritious and balanced diet with lots of fermented foods or prebiotics may be useful to keep your gut happy during times of poor sleep or insomnia.
Sleep affects processes that keep your heart and blood vessels healthy, including those that regulate your blood sugar, blood pressure and tissue repair. These processes are dysregulated when you don’t get enough sleep. Sleep deprivation also causes a rise in stress hormones and inflammatory proteins in your blood, which can be detrimental to your heart. According to the American Heart Association, people who sleep less than 7 hours per night face a host of cardiovascular risks, including obesity, high blood pressure and diabetes.
The endocrine system produces hormones that regulate a variety of bodily functions. Hormone production is dependent on your sleep. For example, hormones that regulate appetite are profoundly influenced by sleep duration. Usually your brain knows that you do not need food due to an appetite-suppressing hormone. Sleep deprivation shuts down this appetite-suppressing hormone and triggers a hunger-driving hormone, causing hunger pains and cravings. As a result, sleep deprived people tend to overeat and have a much higher risk for becoming overweight or obese.
Sleep deprivation also lowers testosterone as well as suppresses growth hormones. Because hormones drive so many bodily functions, trying our best to regulate our sleep patterns (through bedtime rituals, relaxation techniques, maintaining a well-balanced diet, taking sleep-supporting supplements) is critical to maintaining health and warding off disease.
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Dr. Linda May-Zhang has over 10 years of research experience in nutrition, chronic diseases and pharmacology. She has published over 20 peer-reviewed academic papers in scientific journals. She is also a science writer with a passion for educating the lay public.