People who spend more pre-bedtime hours using the Internet or watching television are more likely to report that they don't get enough sleep, even though they sleep almost as long as people who spend fewer pre-bedtime hours in front of a computer or television screen, survey findings show.

"While many people use electronic media, such as the Internet, it should be noted that the longer media use before sleep can trigger (self-perceived) insufficient sleep," lead researcher Dr Nakamori Suganuma, of Osaka University, Japan, told Reuters Health.

He and colleagues obtained data on self-perceived sleep problems and the use of electronic media prior to bedtime from a total of 5,875 Japanese respondents to two separate Internet-based surveys. Their findings are published in the journal Sleep and Biological Rhythms.

Nearly half of the respondents associated their lack of sleep with electronic media use before bedtime. Those reporting longer electronic media use were also more likely to report insufficient sleep.

Overall, 29 percent of light users (less than 1.5 hours) listed electronic media use as a possible cause of their insufficient sleep. By comparison, 40 percent of medium users (1.5 to 3 hours) and 54 percent of heavy users (more than 3 hours) said the same.

However, longer Internet and television use before bedtime did not correlate with less actual sleep.

While heavy users averaged about 3 more hours in front of computer or television screens than light users, the heavy users averaged only about 12 minutes less pre-workday sleep time than light users.

Notably, Suganuma said, "Internet use affected self-perceived insufficient sleep more than TV watching ... not only in younger Internet users but also in middle-aged or aged Internet users."

Up to 38 percent of the respondents listed accessing the Internet far into the night as a possible cause for their sleep disturbance, while about 25 percent said watching television far into the night caused their sleep problems.

The findings suggest that while heavy computer and television use before bedtime has a small effect on sleep duration, it may have a more significant effect on "sleep demand and sleep quality," Suganuma notes.