Sleep and Alertness

How much sleep do you need to be fully alert? Despite years of research, this is still a controversial subject.

The most popular belief is that people require 8 or more hours sleep each day. However, findings from a recent study shed some doubts on this belief. The study found that people who sleep 6 to 7 hours a night live longer, and those who sleep 8+ hours die younger. The leader of the study, Daniel Kripke, a professor of psychiatry at UC San Diego, said it is possible that people who sleep longer tend to suffer from sleep apnea. Kripke believes doctors’ recommendations that everyone get 8 hours of sleep a night may have been partly influenced by the drug companies that make sleeping pills.

Naturally, the results of this new study are not widely accepted. Some sleep experts argue that there were many flaws in the study, including the study was not set up to test this hypothesis, subjects were selected non-randomly, information was collected by diary, and no distinction was made between weekday vs. weekend sleep.

Other sleep experts say the main problem is sleep deprivation, not over-sleeping. Daniel Buysse, a University of Pittsburgh psychiatrist and immediate past president of the American Academy of Sleep Medicine, states “You should sleep as much as you need to feel awake, alert, and attentive the next day… I’m much more concerned about people short-changing themselves on sleep than people sleeping too long.”

The fatigue caused by sleepiness often leads to health problems not measured in the study. James Walsh, president of the National Sleep Foundation, said “The amount of sleep you get impacts how alert you are, your risk for accidents, how you perform at work and school.”

From our own surveys, we have found that the average shiftworker claims he or she needs only about 7 hours to be fully alert. These figures do not vary significantly by gender, age group, or shift worked. When shiftworkers are questioned about sleep habits on their days off work, the average hours of sleep are 7.51.

Sources:

1 Shankar Vedantam, “8 hours of sleep is termed unneeded,” SF Chronicle, Feb. 15, 2002

2 Sandman, “Sleep in the News,” Sleepnet.com Snoozeletter, Feb. 18, 2002