If you're stuck in your cubicle most of the summer, look on the bright side: A host of stress-related ailments can crop up during vacation, ranging from leisure sickness to heart attacks.

Leisure sickness is a cluster of cold- and flu-like symptoms that only strike on weekends or vacations. The syndrome commonly afflicts overachievers who feel guilty about taking time off, Dutch researcher Ad J.J.M. Vingerhoets found. Caffeine withdrawal may also play a role among those who skip their normal java.

Vigorous vacationing can also be hard on the heart. The beginning of a holiday involves unaccustomed physical and emotional stress. In a 2003 report in Psychosomatic Medicine, a team of Dutch and U.S. researchers warned people with heart conditions to be wary of unaccustomed exercise, extreme temperatures, heavy meals and foul-weather driving. Other cardiac stressors include arguments with travel companions and the lack of privacy in shared accommodations.

And if a flurry of catch-up work is waiting, long vacations can make returning to the job especially painful. In a 2002 study, Gerhard Strauss-Blasche of the University of Vienna found that high post-vacation workloads can quickly undo the stress-reduction benefits of a holiday. He suggests easing the transition so that you're not immediately back at full-throttle: Build into your vacation a few half-days of work before you return to the grind full time.