Written by Dr. Carlene Wilson
One hundred years ago, the average American slept almost nine hours every night. Today, with factories running non-stop, 24-hour television programming, and stores that stay open all night, Americans average about seven hours of sleep per night. Many circumstances rob us of our sleep. When both parents in a family are working all day, household chores, children’s homework, and social activities must be crammed into the evening hours. Suburban living means a long daily commute for many workers, with less time at home to relax. Nighttime entertainment such as television, video games, and social networking on the Internet eats up hours that would otherwise be spent in sleep. Add to that a strong work ethic that frowns on laziness and encourages people to sacrifice sleep in order to accomplish more.
Your brain and your body are not idle, however, while you sleep. During those hours, your body does most of its repair work, rebuilding muscle tissue, and restoring the body’s energy supplies. We know that the body secretes growth hormone during sleep. During periods of deepest sleep, blood flow is directed away from the brain towards the rest of the body. While you sleep, your brain organizes and processes new information you have learned during the previous day, establishes neural connections that strengthen your memory, and produces chemicals such as serotonin and dopamine that improve your mood during the day. A good night’s sleep is not a luxury, it is a necessity if you want to feel and perform your best.
An estimated 20% of all adults do not get enough sleep. Sleep deprivation is linked with health problems including diabetes, heart disease, and weakened immune responses; and with increased risk for depression and substance abuse. Lack of sleep also diminishes a person’s ability to pay attention, react to signals or remember new information. The annual economic impact of sleep-related accidents in the U.S. is estimated at between $43 and $56 billion.
Lack of sleep can also make you fat. A national poll of 1,000 adults in 2008 conducted by the National Sleep Foundation found that respondents who slept less than six hours on weekdays were significantly more likely to be obese than those who regularly slept eight hours or more. Several studies have linked sleep deprivation with higher body mass index (BMI) in both adults and children. The amount of time you sleep directly affects levels of leptin, a hormone that suppresses appetite, and ghrelin, a hormone produced by the stomach that stimulates appetite. People who sleep less than eight hours tend to have lower levels of leptin and higher levels of ghrelin in their bodies. Sleep deprivation is also associated with central body fat distribution.
The amount of sleep a person needs to lead a happy and productive life varies with age, level of physical activity, and genetic characteristics. Newborn babies sleep 12 – 18 hours per day, dropping to 14 – 15 hours of sleep after 3 months. Preschoolers need 11 – 13 hours of sleep, elementary school students about 10 – 11 hours, and teens 8.5 – 9.25 hours. Adults need between 7 and 9 hours of sleep per night. Sleep patterns also vary with age: young children often nap during the daytime, and elderly people sleep more lightly with frequent interruptions. An adolescent is typically a “night person,” lively and alert late at night and sleepy at 8:00 in the morning.
Take a moment to assess your sleep habits. How many hours do you sleep every night? Do you wake up feeling refreshed? Does anything prevent you from sleeping or interrupt your sleep during the night?
Here are some tips for getting the most out of your sleep time: