I was in sunny Santa Monica, Calif., sitting by the pool, a situation I would have enjoyed more without a migraine. In New Orleans, my family went shopping in the quaint boutiques lining Magazine Street while I lay in bed nursing a cold. I've skipped dinner at a restaurant in Rome to recuperate on an Airbnb sofa.

I've gotten sick on vacation so often that I've come to anticipate it. I pop vitamin C pills weeks before departure. I pack medicines as routinely as I do toothpaste. Just as I start to relax, my body revolts.

Could it be all the stress of getting away? I rush to complete extra tasks at work. At home, I pack and manage vacation logistics. By the time I get on the plane, I'm exhausted.

Turns out, I'm not alone in what I call leisure fever. Actually, it's common enough that there's a real name for the syndrome — the letdown effect — and science to explain it.

When we are stressed, our bodies respond by ramping up certain hormones that help us through the rough patch, but can also send us crashing when they dissipate. It's akin to my college days, when I'd get sick only after final exams.

One of the hormones that surges during stress is adrenaline, which pushes us through all those nasty deadlines and boosts our immune system. When it recedes, though, our immune system is vulnerable. Cortisol comes on strong, too, and while it helps with stress, it can reactivate latent infections, which then rear their ugly heads a few days later — like when you just want to ride a bike along an ocean path.

So what can you do to stem the letdown effect? Avoid getting so worked up to begin with. Adjust your workflow weeks before your departure; don't cram all that extra work into the last few days before you depart. Call on your colleagues to help. Also, get exercise, rest and healthful meals in the weeks leading up to your departure. Think of it as taking mini staycations to ensure the real vacation.

Send your questions or tips to Travel Editor Kerri Westenberg at travel@startribune.com, and follow her on Twitter: @kerriwestenberg.