Those who employ it know a strong work ethic is more than productive; it has psychological benefits. Staying busy can help keep one from wallowing, dwelling, or succumbing to (short-term) depressive feelings; applying that nugget of wisdom helped our family get through a tough mourning period last year.

Yet no extreme is healthy. Working too much, peer-reviewed research tells us, can make you stupider. No kidding.

Cited in the American Journal of Epidemiology in 2009, a long-term British study of 2,124 middle-aged civil servants (mostly men) showed the magic weekly number seems to be 55 - regularly working more hours than that impairs cognitive function. Researchers collected data over two periods, 1997-1999 (baseline) and 2002-2004, using five different tests to measure memory, reasoning skills, vocabulary, and language.

Compared to those working an average 40 hours per week, the 55-plus group scored lower, especially on vocabulary and reasoning. Wanting to make sure other factors weren't at play, the researchers of "The Whitehall II Study" used other data potentially affecting brain function to see if it made a difference. It didn't; adjustments for age, gender (no comment), marital status, education, occupation, income, diseases, education level, sleep disturbances, and health risk behaviors (e.g., alcohol after-hours) did not significantly affect outcome.

The study authors wrote, "(T)he difference in aspects of cognitive functioning between employees working long hours and those working normal hours is similar in magnitude to that of smoking, a risk factor for dementia which has been found to affect cognition."

The Whitehall II Study supports previous findings, including a 1996 Boston University study of automotive workers. The BU study concluded that increased overtime was "significantly associated with impaired performance" on tests measuring attention and work function. Also associated with more overtime were feelings of depression, fatigue, and confusion.

In other research, chronically long work hours are associated with heart and immune diseases, sleep problems, diabetes, fatigue, and depression. Researchers in areas of neurology, Alzheimer's, and dementia (the strongest correlation) say it also negatively impacts these factors occurring earlier, in midlife.

So what does all this mean? It sure doesn't go so far as to suggest working less makes you smarter. In fact, research has proven experience, as well as continuing education, continue to increase intelligence throughout life. Generally, cognitive decline in active ("active" includes physical and mental) people does not begin until after age 80.

It does suggest balance; like any extreme, neither too little, nor too much, works best. Burning the midnight oil can do a worker more harm than good, and in today's economic climate of downsizing, squeezing more out of us all, the employer doesn't benefit from poor performance.

So what's the practical answer, when work must be done? Efficiency. Studies and common sense indicate interruptions erode concentration and performance, so maybe systematically reducing these will help get more done in less time.

Try these tips:

1. Plan communications. Ignore texts, set phones to voice mail, and return calls and handle emails at a scheduled time.

2. Ditch the chit-chat. Close that Facebook or Twitter window, turn off the distracting "dings" from cell phone alerts, don't do personal email during work, and avoid or politely dismiss chatty coworkers.

3. Plan. Have a daily workplan each morning. Review daily activities; ask what you can stop doing, and categorize/streamline what you do. Work by subject/type instead of switching back and forth.

4. Unclutter work space by organizing in piles or files. Cluttered space, cluttered mind - research supports this idea; clutter and disorganization are linked to stress.

5. Work according to your personality. A morning person? Do the high-concentration (or more dreaded) stuff when your mind is at its best, not when you're craving that post-lunch siesta. That's a good time to return calls and email, or do something mundane.

6. Keep lists. To-do lists, a running one and a daily-maintained calendar help keep you organized. Physically crossing off items as you go actually provides a mental lift of satisfaction and control.

"Efficiency is doing things right; effectiveness is doing the right things." - Management consultant Peter Drucker

Sholeh Patrick is a columnist for the Hagadone News Network. Contact her at sholeh@cdapress.com.