Dr. Gregg Jacobs Reviews the National Sleep Foundations's 2002 Poll

By Dr. Gregg D. Jacobs

The National Sleep Foundation's 2002 "Sleep in America" poll, which involved a sampling of adults ages 18 and older, revealed some interesting and important, findings about American's sleep behaviors. These findings have important implications for our understanding about sleep requirements, insomnia and other sleep disorders, and the effects of sleep loss.

Perhaps the most important finding of the Sleep in America poll pertains to the number of hours Americans sleep. On weekdays, respondents reported sleeping an average of 6.9 hours while, on weekends, they reported sleeping 7.5 hours. Combining these figures for the entire week, people sleep about 7 .1 hours per night. These findings corroborate a recent major study by Dr. Daniel Kripke and his colleagues on over a million people, which found that the majority of Americans report sleeping less than eight hours per night.

Although media reports and some sleep researchers assert that we need at least eight hours of sleep per night, these findings do not support this notion.. If we need at least eight hours of sleep, we would expect that the sleep durations of people in the real world would cluster around eight hours, not seven. In fact, a closer analysis of the Sleep in America Poll reveals that 40% of Americans sleep less than 7 hours, and a full 70% sleep less than eight hours per night. For the vast majority of people, the natural homeostatic drive for sleep in the real world (versus the results of findings on young adults in a sleep laboratory) is under eight hours per night.

Regarding insomnia, 35% of respondents reported experiencing the symptoms of insomnia every night and 23% reported insomnia at least a few nights per week. Thus, over half of respondents experience insomnia at least a few nights per week. The most common type of insomnia was being awake during the night (as opposed to difficulty falling asleep). Only 6% of people who report insomnia have been diagnosed with insomnia by a health care professional, and even fewer (4%) have received treatment for insomnia. These findings clearly show that, despite the fact that the majority of Americans experience symptoms of insomnia, the vast majority go undiagnosed and untreated despite he availability of effective interventions such as cognitive-behavioral therapy.

Another important finding from the poll was that the majority of respondents (63%) rarely or never experience daytime sleepiness and only a small minority (7%) experience sleepiness on a daily basis. In conjunction with the findings on sleep durations, these findings suggest that most people do not feel sleep-deprived in daily life and that an average of about seven hours of sleep is sufficient to maintain alertness in daily life.

Although the media and some sleep researchers claim that we need at least eight hours of sleep to maintain daytime alertness, 70% of respondents report that they need less than eight hours of sleep to feel alert. In addition, the majority of people who sleep less than eight hours report positive mood during the day, feel optimistic, and are satisfied with their lives. Thus, sleep duration of less than eight hours not only maintains subjective alertness but also positive mood and outlook on life.

Finally, 90% of respondents believe that sleep deprivation can lead to health problems despite the fact that there is no conclusive scientific evidence that sleep deprivation can lead to health problems. The only widely accepted effects of sleep loss are primarily mood disruption and, secondarily, sleepiness. Apparently, the American public has been increasingly influenced by negative, distorted media reports about the effects of sleep loss that have not presented a complete, accurate picture of the effects of sleep deprivation.