Why do we need sleep?
People who can get by on four hours of sleep sometimes brag about their strength and endurance. But recent scientific studies show that a lack of sleep causes many significant changes in the body and increases your risk for serious health concerns such as obesity, disease, and even early death.
Sleep is an important function for many reasons. When you sleep, your brain signals your body to release hormones and compounds that help:
decrease risk for adverse health conditions
manage your hunger levels
maintain your immune system
But you can’t catch up or make up loss of sleep. In fact, consistently sleeping more than six to eight hours a night can negatively impact your health. Read on to learn why seven to eight hours of sleep a night is ideal.
Seven to eight hours for longevity
The healthy amount of sleep for the average adult is around seven to eight hours each night.
Researchers in the United Kingdom and Italy analyzed data from 16 separate studies conducted over 25 years, covering more than 1.3 million people and more than 100,000 deaths. Trusted Source
Those who generally slept for less than five to seven hours a night were 12 percent more likely to experience a premature death. People who slept more than eight or nine hours per night had an even higher risk — 30 percent.
Researchers also found that people who reduced their nightly sleep time from seven to eight hours to below seven hours were at an increased risk of death from all causes. Additionally, the researchers also saw an increased risk of death from all causes in those who slept for a long amount of time per night.
Sleep helps manage your appetite
Poor sleep habits can increase the body’s energy needs. At night, movement and the need for calories is reduced. But when you are sleep-deprived, your brain will release chemicals to signal hunger. This can lead to eating more, exercising less, and gaining weight.
Sleep deprivation also affects children. A 2014 study showed that children who slept less had an increased risk for obesity and high BMI. These risks can affect children as they mature.
Sleep helps your immune system function
When you sleep, your immune system releases compounds called cytokines. Some cytokines have a protective effect on your immune system by helping it to fight inflammation, including inflammation due to infection.
Without enough sleep, you may not have enough cytokines to keep you from getting sick. Other components of the immune system, like antibodies and white blood cells, can be reduced over time without enough sleep.
A 2013 studyTrusted Source found that sleep restrictions increase the amount of inflammatory compounds and activity in a person’s body. These are the same compounds associated with conditions like asthma and allergies.
The researchers studied people who underwent limited sleep deprivation of four hours a night for 5 days in a row. Before and after these 5 days of limited sleep deprivation, two nights in a row of 8 hours per night of sleep time were part of the experimental protocol utilized in the experimental group subjects.
In comparing their study subjects with limited sleep deprivation to other studies where the subjects had long-term sleep deprivation, the researchers found that the participants’ immune systems were affected regardless. Even with a short period of limited sleep deprivation, the immune system was affected in ways similar to those with long-term sleep deprivation.
Sleep helps your memory
In addition to helping you focus, sleep helps protect and strengthen your memory. Research shows that sleeping after learning can help with memory retention. Sleep is also thought to reduce interference from external events.
People who are sleep-deprived:
have a harder time receiving information due to the brain’s overworked or fatigued neurons
may interpret events differently
tend to have impaired judgement
lose their ability to access previous information
It’s important to get seven to eight hours of sleep so that you can experience all the sleep stages. No one stage is responsible for memory and learning. Two stages (rapid eye movement and slow-wave sleep) contribute to:
Lack of sleep increases disease risk
Lack of sleep is known to be a contributing factor for many chronic health conditions, including:
obstructive sleep apnea
Sleep is a habit, just like eating healthy and exercise. While everyone misses a few hours of sleep sometimes, chronic lack of sleep is part of an unhealthy lifestyle and can increase your risk for serious health concerns.
Having a poor work-life balance, stress, and worry can all affect how much and how well a person sleeps. These kinds of stressors can lead to further inflammation and health problems in addition to lack of sleep.