Why Do You Always Get Sick on Holiday? Experts Explain the ‘Let-down Effect’

Your body may be quietly working against you the moment you finally get the chance to relax. According to health experts, the timing of that sudden cold or migraine is no coincidence.

After weeks, perhaps even months, of meticulously planning a vacation and finally arriving at your destination, the last thing anyone wants is to fall ill and miss out on their hard-earned break.

Unfortunately, so many people have experienced this exact scenario that it now has a name: the "let-down effect." And the phenomenon isn't limited to vacations, either.

Right after a stressful stretch ends, whether it's a nerve-racking work project or a serious family emergency, sickness can catch you off guard at the very moment you finally exhale and start to relax. Put simply, the second you let your guard down, your body's defenses may do the same.

"You have this mobilization of inner energies to take action on something big, and afterward you think you'll be exhilarated because you accomplished it, but you could have this letdown instead," says psychologist Shilagh A. Mirgain. "And if people aren't prepared for it, it can be a crash. The higher the accomplishment, the bigger the crash."

"This effect has been associated with conditions such as upper respiratory infections, the flu, migraine headaches, dermatitis, arthritis pain, and depression," says Dr. Mark Schoen, a psychologist and assistant clinical professor of medicine at UCLA who has studied the phenomenon extensively.

Paul Rosch, MD, president of the American Institute of Stress and clinical professor of medicine and psychiatry at New York Medical College, agrees that while people respond to stress differently, "when individuals are subjected to chronic stress, some of them are going to show physical or psychological effects even after the stress itself is relieved."

During periods of intense pressure at work or at home, the body produces a range of chemicals, stress hormones among them, that rally the immune system to fend off illness.

Once the pressure lifts, though, the immune system stands down, and the body grows less alert to potential threats. Meanwhile, according to Schoen, a buildup of chemicals known as prostaglandins, lingering from the stress response, can cause inflammation and set off issues like joint pain and migraines.

"Illness during this let-down period may come in two ways," according to Schoen, author of "When Relaxation Is Hazardous to Your Health."

"It could be related to something we were exposed to in the throes of stress. Or it might be something that develops afterward through this open window, where any organisms around us have a far greater chance of infecting us."

Thankfully, there are several ways to counteract the let-down effect:

• Move in short bursts: Schoen recommends gently activating the immune system so it doesn't slow down too quickly after stress. Even five minutes of exercise can trigger a positive immune response. "Walk up and down the stairs in your office building," says Schoen. "Or after a stressful day at work, instead of coming home and vegging-out in front of the TV, take a brisk walk for a few minutes."
• Challenge your mind: Try timed mental tasks, like crossword puzzles. "Several studies show that doing math computations at a rapid pace actually increases immune-system activity," says Schoen.
• Breathe deeply: Inhale slowly and deeply, exhale naturally, and focus on the gentle rise and fall of your abdomen. This simple form of meditation can lower your heart rate, slow your brain waves, and even reduce your blood pressure.

Between long flights, crowded airports, and the germiest spots in your hotel room, travelers already have plenty of reasons to worry about getting sick on vacation.

While the let-down effect can feel like a cruel twist of fate, simply knowing it exists is half the battle. By easing out of stressful periods gradually rather than crashing straight into rest mode, you may be able to protect both your health and the downtime you worked so hard to earn.