Many of us are working longer, taking our work home with and that's costing us our much-needed sleep, finds a new survey.

The survey of 1,000 people from the National Sleep Foundation in the U.S. finds that most of us are sleeping an average of six hours and 40 minutes a night on weeknights.

That's despite the fact that the survey found that the average respondent said they needed seven hours and 18 minutes of sleep to be at their best.

Part of the reason we're sleeping less is that we're working more as the era of the 8-hour workday seems to slip away.

One-fourth of respondents have a workday that lasts between eight and nine hours, another fourth say that they work between nine and 10 hours each day, and nearly a third report working 10 or more hours each day.

And even when the workday day is done, the work itself is not. Many of us are taking our work home with us the survey found. Almost one-quarter (23 per cent) of all respondents said they did job-related work in the hour before going to bed at least a few nights each week.

Of those who regularly take their work home with them, 20 per cent say they spend 10 or more additional hours each week doing work at home; another 25 per cent spend at least seven additional hours each week on job-related duties.

All that working and not enough sleeping takes a serious toll on people's professional and personal lives. The poll found 29 per cent reported falling asleep or becoming very sleepy at work in the past month. It also found that 36 per cent have nodded off while driving, with 32 per cent reporting that they drive drowsy at least 1 to 2 times per month.

As well:

  • 14 per cent have missed family events, work functions and leisure activities in the past month due to sleepiness
  • 12 per cent were late to work in the past month because of sleepiness
  • 28 per cent said that daytime sleepiness interferes with their daily activities at least a few days each month
  • 20 per cent have sex less often or have lost interest in sex because they are too sleepy

Many of us try to catch up on our sleep on the weekend but even that may not be enough.

Nearly a third (32 per cent) of those surveyed say they only get a good night's sleep a few nights per month. But National Sleep Foundation vice chair Thomas J. Balkin says there comes a point when one simply cannot "catch up."

"Studies show that habitually getting inadequate sleep -- less than seven or eight hours of sleep each night -- creates long-lasting changes to one's ability to think and function well during the day," he said in a NSF news release.

"These negative effects can accrue slowly over weeks, months, and even years of inadequate sleep habits and cannot simply be reversed by a few nights of good sleep."