In Europe, 4 to 6 weeks of vacation are mandated by law. Compare that to the U.S., where we have no such mandates and are sometimes asked to give up our vacation time for a pressing project. According to Joe Robinson, author of Work to Live, those European countries with mandated vacation are all as productive or in some cases, more productive than the U.S. Studies have shown that when you do take time for vacations, your overall performance improves. Vacation time, which doesn't include "working vacations" of checking e-mail and still actually working, renews the spirit and provides fresh inspiration.
The news is worst for women workaholics. The Marshfield Clinic in Marshfield, WI conducted a study of 1500 working women and found that women who only had a vacation once in 6 years were twice as likely to report damaging problems to their health such as hypertension, anxiety, and depression, than women who took regular vacations each year.