Even as American productivity has risen by an average of nearly 3 percent a year over the past five years, a new poll shows a third of Americans also get less sleep than they did five years ago.

Overall, the National Sleep Foundation reported Tuesday that 62 percent of adults get less than eight hours of sleep on a weekday night and a third say they're getting by on six hours or less.

Forty percent of the 1,004 adults surveyed said they are working more than they were five years ago, while 30 percent said they're working less. At the same time, 38 percent said they're spending less time sleeping. While the average reported workweek was 46 hours, more than a third said they're putting in 50 hours or more at a job each week.

``There is a direct relationship between hours worked and its negative impact on sleep. This is particularly noticeable for people working more than 40 hours a week,'' said James Walsh, vice president of the nonprofit foundation, which promotes public education about sleep and sleep disorders.

Across the board, the survey found American adults are not only spending less time sleeping, but also less time engaging in social and leisure activities and even having sex than they did five years ago.

Sleeping less to try and do more is taking its toll. More than half of those surveyed say they experience frequent symptoms of insomnia, like waking up feeling un-refreshed or awakening frequently during the night.

Four in 10 of those surveyed said they get so sleepy during the day that their ability to work or perform other activities is impaired at least a few days a month, while 7 percent say it's a daily occurrence.

But when they feel sleepy, 65 percent said they're very likely just to accept how they feel and keep going. Fifty-three percent said they'd driven a vehicle while feeling drowsy during the past year, while 19 percent said they'd actually fallen asleep and 1 percent admitted having an accident after dozing off.

To try and stay awake, 43 percent said they're very likely to drink coffee or other caffeinated drinks, and 5 percent use stronger stay-alert medications. Climbing into bed, about 11 percent said they use a medication to help them fall asleep at least a few nights a month.

The survey did show that Americans are worried about being so tired and don't want to give up any more sleep, and more than 80 percent said they'd sleep more if they knew it would make them healthier, improve their memory or help them perform in a safer way and avoid injuries.

``That is, of course, exactly what will happen if you get adequate sleep,'' said Richard Gelula, executive director of the sleep foundation. ``Clearly, we have our work cut out for us to educate Americans that a good night's sleep is a necessity, not a luxury.''

On the Net:

http://www.sleepfoundation.org.