A shortened period of sleep may contribute to various ills, including memory lapses, trouble learning and paying attention, heart disease, obesity, mood problems and a weakened immune system.
One or two sleepless nights or a bout of insomnia now and then is nothing to worry about. But not getting enough sleep night after night is a concern.
How much sleep do we need? Some people do well with six hours a night; others need nine or more. Experts think seven to nine hours is about right. If you wake up refreshed and can stay awake and alert throughout your day, you're probably OK. If not, here are six reasons to consider changing your current sleep habits.
1. Learning and memory
Sleep helps your brain commit new information to memory. People who get a good night's sleep before taking tests or performing a new task usually do better than people who are tested immediately after learning something new. Other studies seem to show that people are more insightful or creative in their problem solving after getting a full nights sleep.
A constant lack of sleep may cause weight gain by altering the way the body processes and stores carbohydrates, and by stimulating the release of cortisol, a stress hormone. Excess cortisol has been linked to an increase in abdominal fat. Loss of sleep also reduces levels of leptin, a hormone that suppresses appetite, and increases ghrelin (GRELL-in), an appetite-stimulating hormone a combination that can encourage eating.
Theres no evidence that we ever adapt to chronic sleep loss. This sleep "debt" contributes to daytime sleepiness, including microsleeps, seconds-long daytime dips into sleep. These lapses may cause falls, injury and road accidents. The National Highway Traffic Safety Administration estimates that each year, drowsiness causes 100,000 vehicle crashes, resulting in 76,000 injuries and 1,500 deaths.
4. Quality of life
Long- and short-term sleep loss causes irritability, impatience, inability to concentrate and moodiness. Too little sleep can leave you so tired that you dont want to spend time with family and friends or have sex. Poor sleep affects the ability to work. Sleep disorders such as insomnia and sleep apnea are associated with depression.
5. Heart and lung health
We dont know much about how chronic sleep loss affects heart health and our lungs. But serious sleep disorders such as insomnia and sleep apnea have been linked to high blood pressure and irregular heart beat. Lack of sleep increases stress hormone levels and inflammation, two factors associated with heart attacks.
Although not all the facts are clear, scientists have found that sleep deprivation alters the body's immune system, which fights off illness. For example, sleep loss around the time of a flu shot has been shown to reduce the production of flu-fighting antibodies.