People are spending way too much time sitting at desks, researchers warn. The average office worker spends five hours 41 minutes at the desk on a work day -- that's nearly as much time as a nightly sleep, according to a new study.

The Loughborough University study of over 1,000 employees found that nearly 70 percent of employees surveyed did not meet recommended guidelines for physical activity. Among the findings are: A correlation between BMI scores and sitting time at work, as one would expect. Those who sit for longer at work were also more likely to spend the most time sitting down when they got home. And more time spent sitting at work was associated with a decrease in mental well-being.

"We need to be aware of how much we sit," says occupational psychologist Dr. Myanna Duncan who conducted the study. "People don't need a psychologist to tell them to get up and walk around. But if it helps, I'd tell them to put a post-it note on their computer to remind them."