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When people hear that I am a sleep specialist, invariably one of three questions arises:
- What sleeping pill do I recommend?
- Is there anything besides CPAP for sleep apnea?
- And, how much sleep do people need?
My question is: Why are people so interested in the amount of sleep they are getting?
This topic has generated much interest over the past few years. Newspaper articles, blogs, TV, books, and websites talk about every sleep disorder imaginable, and shed wisdom on how to solve your perceived sleep problem. Many question the amount of sleep a person really needs.
For years, we have been told that adults should get between seven and nine hours of sleep. If a person's sleep deviates from that range, they are perceived to be at an increased risk of hypertension, heart attacks, stroke, obesity, automobile accidents, and even death. The National Sleep Foundation recently published recommendations on how much sleep people should be getting at various ages.
There are two things one must remember when reading such recommendations. First, an association between a bad outcome (for example, death) and too much sleep does not mean that too much sleep causes death. Second, one must also remember that such recommendations are for a population of people, not a single person.
I will now elaborate on both of these issues:
Research has shown that death rate increases in populations that sleep more than 10 hours or less than six. This could imply that, somehow, the amount of sleep directly leads to death. It is very conceivable, in fact likely, that people who sleep too much in a 24-hour period have a sleep disorder such as sleep apnea, and that the condition is causing death—not the amount of sleep. Similarly, if people sleep much less than six hours, they may have symptoms that cause reduced sleep, such as severe pain. These symptoms may be caused by cancer, heart failure, or sleep-breathing problems that may result in an increased death rate.
The type of research that examines these associations is conducted in populations. Populations are made up of individuals with different genetics, environments, levels of activity, diets, and underlying medical conditions. Thus, this type of research yields a range that covers most of the population, but not all individuals within a population.
What about people who sleep very little, or who keep unusual schedules: Are they always risking their health? The answer is no. I recently encountered several people who slept very little and were wide-awake, alert, and feeling great without medical problems. One slept three out of 24 hours. Another was a shift worker who worked nights, and slept between 11 a.m. and 1 p.m., and then again between 7 and 9 p.m. He only slept four out of 24 hours! He had been referred to me to "improve his sleep," although he had no intention of changing his sleep pattern. His “abnormal” sleep habits had remained the same for about three decades without any residual health or mood problems during that time.
A renowned scientist I know told me about an unusual schedule he adopts when he has a tight deadline involving the submission of grants. He stays awake all night, then sleeps from 5 to 8 a.m., works all day, then sleeps again from 6 to 9 p.m. He is his most creative between 11 p.m. and 5 a.m. He has been very successful in securing grants and publishing great work (although I would not want him to be the pilot of an airplane I was flying in).
Great athletes, stage actors, and others may also adopt "unusual" sleep patterns, and end up sleeping much more than the “recommended” seven to nine hours. Accomplished athletes like LeBron James, Roger Federer, and many others sleep a great deal; in fact, some athletes often nap right before an evening game. They appreciate the extra edge in alertness that additional sleep provides. It also allows their bodies to recover from grueling activity. Professional sports teams now pay close attention to their athletes’ circadian rhythms and sleep needs.
Stage actors may be so revved up after an evening performance that they cannot sleep for several hours after the performance, yet may sleep until early afternoon the following day unless they have a matinee performance.
Thus, the answer to the question, “How much sleep do you need” is quite easy: It is the amount of sleep that leaves you wide-awake, alert, in a great mood, and functioning at your best.
Let me know how much sleep you need. . .
National Sleep Foundation’s sleep time duration recommendations: Methodology and results summary
