The OECD report states that survey methods may vary to some degree between the 18 participating countries. In the U.S., the American Time Use Survey includes people 15 years of age and older.
The survey is conducted by telephone. Respondents report how long they slept between 4 a.m. on the previous day and 4 a.m. on the day of the survey.
So the survey doesn’t measure a person’s typical sleep duration. And “sleep time” includes both nighttime sleep and daytime naps.
The average self-reported sleep times in the survey vary by age. The 2007 American Time Use Survey shows that teens and older adults get the most sleep. Teens report sleeping about 9.5 hours per day; adults age 65 and up get about 8.9 hours of sleep per day.
People in the U.S. also tend to sleep in on the weekends. The 2007 survey shows that Americans sleep about 9.2 hours on weekend days; this is almost an hour more than the 8.3 hours they report sleeping on weekdays.
But these numbers don’t tell the whole story. The broad strokes of this survey fail to paint an accurate picture of sleep problems in the U.S.
Another survey by the NCHS shows that many U.S. adults get much less sleep on a regular basis. About 21 percent of adults reported that they usually sleep for only six hours; another eight percent usually sleep for less than 6 hours.
The OECD report and the American Time Use Survey also fail to take sleep disorders into account. It is estimated that 50 million to 70 million people in the U.S. suffer from a sleep disorder.
Common disorders such as sleep apnea can ruin your sleep quality. This can impair your health and alertness no matter how many hours of sleep you get.