We're happiest when looking forward to vacations, though once back in the office that level of glee is comparable to our non-vacationing cubicle mates, a new study finds. Essentially, vacations may not be the restorative respites they are chocked up to be.

The researchers surveyed 1,530 Dutch adults, 974 of whom took a vacation during the 40-plus week study period. At certain time points both before and after trips, participants answered questions related to their happiness levels.

Those in the planning phase of a vacation had higher happiness scores than those not going away, which the researchers say, is likely due to holiday anticipation. Following the trip, vacationers and non-vacationers showed no difference in their happiness levels, that is unless the time off was considered very relaxing. In that case, there was a slight happiness boost for vacationers noticeable during the first two weeks back. After eight weeks, that slight increase had faded completely, the scientists found.

The research team isn't surprised by the short shelf-life for this vacation boost. Most vacationers go right back to the daily grind pretty quickly upon return, according to Jeroen Nawijn of Erasmus University in Rotterdam in the Netherlands. In addition, past research has shown that for many people, vacations are fully-wired, so they're just an e-mail or text-message away from the office and the relaxation potential is not fully realized.

"I believe that after the trip people fall back into their normal routines very quickly. A heavy workload after returning to work, laundry to take care of, groceries to buy, kids going to school again and adjusting to that," Nawijn told LiveScience. "All of these things are probably contributing to the absence of a post-trip happiness difference between vacationers and non-vacationers."

Nawijn added that while the research involved Dutch individuals, the results would likely hold up for Americans though it's easier for those in the Netherlands to take an international trip.

The take-home messages: First, to get the most happiness bang for the buck, people might want to take two or more short breaks spread throughout the year rather than one long one, according to Nawijn, who is also affiliated with NHTV Breda University of Applied Sciences.

Secondly, to help families stagger their vacations, school systems need to become more flexible, the researchers say. And lastly tourism managers should provide vacation experiences that are as stress-free as possible.

The research is published in the Feb. 10 online issue of the journal Applied Research in Quality of Life.