By Lisa Young, Health Educator, U.S. Army Public Health CommandFebruary 28, 2014
What happens when you are asleep?
The brain stays active during sleep performing activities that allow a person to feel rested and energetic, learn, and make memories. Sufficient sleep is followed by spontaneous awakening that leaves a person feeling refreshed and alert. Vital tasks carried out during sleep help maintain good health and enable people to function optimally. Not getting enough sleep can be dangerous to mental and physical health. In fact, having adequate sleep is so important that it is an element of the Army's "Performance Triad," the idea that we all need a balance of sleep, activity and nutrition to lead a healthy lifestyle.
How much sleep is enough?
Sleep needs vary from person to person, and they change throughout life. How much sleep is needed depends on genetic and physiological factors and will vary by age, sex and previous sleep amounts. Most adults, including older adults, need seven to eight hours of sleep each night. Children and adolescents have greater sleep needs, depending on how old they are.
How does deprived sleep change performance?
A recent study from the National Health Interview Survey found that 30 percent of workers reported sleeping six hours or less per night. This kind of sleep restriction produces negative consequences for performance, health and quality of life, with profound personal and public safety consequences. The study also indicates that although performance declines as sleep restriction increases, the person's assessment of his/her sleepiness levels off after a few days. This means that sleep-restricted people are likely to be unaware of their continuing deterioration in alertness and performance.
We need to sleep to think clearly, react quickly and improve memory. Cutting back by even one hour can make it tough to focus the next day. Slow response time, may result in making bad decisions and taking more risk. This behavior can result in poor performance on the job and increase the risk for an accident or car crash.
How does insufficient sleep affect our mood?
Insufficient sleep can make a person irritable and is linked to poor behavior and trouble with relationships, especially among children and teens. People who chronically lack sleep are also more likely to become depressed.
What is the effect of sleep on long-term health?
Studies have shown that sleep restriction of four hours per night on just one to two nights has significant effects on the body. Not getting enough sleep or getting poor quality sleep on a regular basis increases heart rate and blood pressure, increases inflammation, impairs glucose tolerance (which can lead to the development of diabetes), and increases appetite that could promote obesity. During sleep, the body produces hormones that help build muscle mass, fight infections and repair cells. A summary of studies from the past 30 years has shown that compared with individuals who sleep seven to eight hours a night, there is an increased risk of dying in people who sleep substantially less than seven hours or substantially more than nine hours per night.
What are the clues to an overly sleep-restricted life?
Symptoms include difficulty awakening in the morning, such as sleeping through the alarm clock, needing stimulants like coffee to wake up or get going each morning, difficulty remaining focused and productive when sitting for a while, negative mood or poor memory.