Last week, we filled our days with finishing up projects at work, selling stuff on Craigslist, and going to goodbye happy hours and dinners. It was awesome, and it was nonstop.

On Sunday, I boarded a bus to New York to visit grandparents. After sitting still for five hours, I ate a relaxing dinner, watched some Real Housewives of Orange County with my grandmother, then I went to bed.

The next morning, helloooo chills and fatigue. A few days later: full blown cold. I slowed down and got sick.

Why does this often happen? I’ll work a three-day conference, I’ll be done with finals, I’ll finish a big project, and when my pace of activity slows, I get sick.

It sucks. A 2007 Guardian article (among other articles) termed this “leisure sickness”: It’s when you fall ill when the weekend hits or you start a vacation.

Professor Ad Vingerhoets, from the department of psychology and health at Tilburg University in the Netherlands, started researching the concept of “leisure sickness” after becoming aware that he suffered from it himself. “I noticed that I was never ill, except occasionally, and then the problems started on Friday at 5pm, and by Monday morning, I had recovered,” he says. “The period between Christmas and new year seemed to be my favourite time to get ill.” He asked around and found that other people had similar experiences.

After conducting his survey of more than 1,800 people, he estimated that around 3% of people suffer from “leisure sickness”. Vingerhoets found that many of those who experienced it shared similar personality traits – they were perfectionists in their work, preoccupied with achievement and took their professional responsibilities very seriously, making it harder to leave it behind. “I think there are three main explanations for it,” says Vingerhoets. “It may be related to a change in habits during the weekend or on holiday, including more or less sleep, coffee or alcohol. Or that during work, our busy jobs direct the brain’s attention away from signals from the body, so when you go to a quiet setting, those signals are suddenly perceived and interpreted as symptoms.”

The third theory is that when you have been busy at work or stressed, your body stays “activated” during the time when you should be resting. “We found that the people with many vague complaints failed to reduce their energy production, or adrenaline. It seems obvious that needless energy may compromise our health and weaken our natural defences.”

Needless energy after packing, saying goodbye, and running around would weaken my natural defenses or lack thereof. But its also completely possible I sniffed in something whenever I had a teary goodbye.

So, is leisure sickness preventable? Perhaps, suggests the article. Ease into vacation slowly and really use the time to relax.

Have you ever experienced leisure sickness? How did you deal with it and how would you prevent it?