Sleep is vital for sustaining the health of major mind-body functions including immunity, stress, fitness recovery, mood, aging, weight, and the brain. Unfortunately, sleep is often the first casualty of our busy lives and worse yet, skimping on sleep sets you up for a host of serious health problems.
Sleep and Weight
Sleep is essential to regulating our metabolic system. Sleep loss can also contribute to obesity in more indirect ways, setting up a vicious cycle: When we’re tired, we’re disinclined to be active, more vulnerable to feeling anxious, and more inclined to eat comfort foods by the light of the refrigerator door.
Sleep and Aging
When the body enters the first stage of deep sleep, it releases a surge of growth hormone. The hormone stimulates protein synthesis, helps break down fat that supplies energy for tissue repair, and stimulates cell division.
This repair process is essential to recovering not just from athletic pursuits but from the wear and tear of everyday life.
While scientists are still only beginning to unravel sleep’s mysteries, nature has made one thing clear: We can’t cheat on sleep without also shortchanging our health, happiness, and perhaps even our life span.
Sleep and Mood
“In study after study, sleep researchers have found that good sleep sets up the brain for positive feelings,” writes William C. Dement, MD, PhD, professor and chief of the Stanford University Division of Sleep, in The Promise of Sleep. “When we don’t have enough sleep, we have a sour view of circumstances: We are more easily frustrated, less happy, short-tempered, less vital.”
Sleep and Fitness Recovery
Sleep’s role in tissue repair and immunity concerns everybody, but it is a particular concern for athletes and other highly active individuals who regularly push their bodies to the limit.
Studies suggest that more significant restrictions in sleep — such as getting only four hours per night — may lead to faster heart rate and lower heart-rate variability, factors that can affect athletic performance and indicate strain associated with cardiovascular risk.
Over time, this can lead to high blood pressure, which can limit the amount of intensive exercise an athlete can safely sustain.
Sleep and the Brain
“If you lose one night of sleep, your mental performance is like you’re legally drunk,” says Alexandros N. Vgontzas, MD, director of the Penn State Hershey Sleep Research and Treatment Center. “We’ve seen this effect even in people who reduce their sleep from eight hours to six.”
And that deficit is cumulative: Your body doesn’t forget a half night of lost sleep; it carries the debt forward into the next day, and the next.
Sleep and Immune System
During sleep, the immune system performs preventive maintenance. Blood levels of immune-system molecules such as interleukin-1 and tumor necrosis factor (a potent cancer-killer) rise tenfold. They decline when we wake.
Studies have linked insufficient or irregular sleep to increased risk for colon cancer, breast cancer, heart disease, and type 2 diabetes.
Sleep and Stress
During sleep, levels of the stress hormone cortisol decrease and we secrete more growth hormone (a key tissue-repair substance). Without enough sleep, cortisol can remain elevated, keeping the body in a state of alertness and driving up blood pressure, which increases the risk of heart attack and stroke.
Sleep deprivation may also lead to a rewiring of the brain’s emotional circuitry and put us into a state of hyperarousal.
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