Chapter 30: Sleep
Lumen Learning and Dave Dillon
The Benefits of Slumber
We have so many demands on our time—school, jobs, family, errands, not to mention finding some time to relax. To fit everything in, we often sacrifice sleep. But sleep affects both mental and physical health. Like exercise and a healthy diet, it’s vital to your well-being.
Of course, sleep helps you feel rested each day. Internal organs and processes are hard at work throughout the night. Sleep can help you “lock in” everything you’re studying and trying to remember.
“Sleep services all aspects of our body in one way or another: molecular, energy balance, as well as intellectual function, alertness and mood,” says Dr. Merrill Mitler, a sleep expert and neuroscientist at the National Institute of Health (NIH).
When you’re tired, you can’t function at your best. Sleep helps you think more clearly, have quicker reflexes, and focus better. “The fact is, when we look at well-rested people, they’re operating at a different level than people trying to get by on one or two hours less nightly sleep,” says Mitler.
“Loss of sleep impairs your higher levels of reasoning, problem-solving, and attention to detail,” Mitler explains. Tired people tend to be less productive at work and school. They’re at a much higher risk for traffic accidents. Lack of sleep also influences your mood, which can affect how you interact with others. A sleep deficit over time can even put you at greater risk for developing depression.
But sleep isn’t just essential for the brain. “Sleep affects almost every tissue in our bodies,” says Dr. Michael Twery, a sleep expert at NIH. “It affects growth and stress hormones, our immune system, appetite, breathing, blood pressure and cardiovascular health.”
Research shows that lack of sleep increases the risk for obesity, heart disease, and infections. Throughout the night, your heart rate, breathing rate and blood pressure rise and fall, a process that may be important for cardiovascular health. Your body releases hormones during sleep that help repair cells and control the body’s use of energy. These hormone changes can affect your body weight.
“Ongoing research shows a lack of sleep can produce diabetic-like conditions in otherwise healthy people,” says Mitler.
Recent studies also reveal that sleep can affect the efficiency of vaccinations. Twery described research showing that well-rested people who received the flu vaccine developed stronger protection against the illness.
A good night’s sleep consists of four to five sleep cycles. Each cycle includes periods of deep sleep and rapid eye movement (REM) sleep, when we dream. “As the night goes on, the portion of that cycle that is in REM sleep increases. It turns out that this pattern of cycling and progression is critical to the biology of sleep,” Twery says.
Sleep can be disrupted by many things. Stimulants such as caffeine or certain medications can keep you up. Distractions such as electronics—especially the ligh