Dear Doctor: My husband thinks that sleeping for more than five hours a night is a waste of time. But I just read that not getting enough sleep can predispose people to illness. Is this correct? I would love to be able to persuade him that sleep is actually good for you.
Dear Reader: Getting enough hours of sleep is crucial to staying healthy. Yet a surprising number of people resist the idea. We will happily tell you what is known about the benefits of sleep and hope that it will be enough to persuade your husband.
People who don't get enough sleep simply don't function as well as those who do. Paying attention at work, staying alert while driving, performing tasks that require decision-making or a judgment call -- all become more difficult when you haven't had enough sleep. Sadly, chronic sleep insufficiency can cause behaviors that lead to injury and death.
Hundreds of studies over the years have shown that a lack of sleep, which is often referred to as "sleep insufficiency," also plays a role in chronic disease. Researchers have concluded that lack of sleep adversely affects the immune system and increases inflammation. Individuals who don't get enough sleep on a regular basis are at increased risk of cardiovascular disease, diabetes, cancer, hypertension and obesity.
How much sleep is enough?
Adults need at least seven hours of sleep per night. For adolescents, that number climbs to nine hours per night. Getting adequate sleep helps regulate the metabolism, keeps emotions on an even keel, aids in reasoning and memory, helps the brain recuperate and plays a role in physical coordination. In fact, sleep is so important to health and well-being that the Centers for Disease Control and Prevention consider the chronic shortage of sleep among Americans to be a public health issue.
Children who don't get enough sleep are more likely to become obese than those who sleep enough. Both children and adults who don't get enough sleep are at increased risk of mental and emotional problems as well. Depression, anxiety, impaired behavior and mood disorders are all associated with lack of sleep.
The latest scientific data to bolster the importance of getting enough sleep comes from a fascinating study published last February. Conducted at the University of Washington Medicine Sleep Center in Seattle, scientists studied 11 sets of identical twins. Although the twins shared identical DNA, their natural sleep patterns differed greatly.
Each of the study participants slept at least seven hours per night. But one twin in each pair slept at least one hour less per night than the other twin. When blood samples collected from each participant were examined, the twin who got less sleep had measurably lower function in the immune system than did the twin who slept more. And, as you noted in your question, this means less sleep can lead to greater susceptibility to illness.
The truth is, we get quite a few questions about sleep, battling insomnia and how to sleep better. We'll address these soon in an upcoming column.
(Send your questions to firstname.lastname@example.org, or write: Ask the Doctors, c/o Media Relations, UCLA Health, 924 Westwood Blvd., Suite 350, Los Angeles, CA, 90095. Owing to the volume of mail, personal replies cannot be provided.)