’Tis the season for shopping, decorating and, let’s face it, catching nasty bugs. When your stress is already at its peak— what with your house full of guests and party season underway— your immune system certainly picks a great time to run amok! You may credit Murphy’s law when you develop the sniffles and a sore throat just as your mother-in-law arrives for her holiday visit, but the very stress associated with hosting her— or organizing that holiday bash, traveling cross-country, or finding the perfect gifts for your hubby and kids— is actually what increases your chances of getting sick. And just why is that? Simply put, the added stress of the holidays elevates your cortisol levels. And high cortisol translates to low immunity.

Here’s a window into how stress can dampen your immune response: It’s the Friday before holiday vacation, and you’re managing crazy work deadlines with the intention to bolt at 5 p.m. sharp to get a head-start on turkey basting. Your cortisol levels rise to cope with the stress, temporarily suppressing your immune system and your body’s ability to fight off viruses and bacteria. You grab a door handle at the office, and moments later you touch your mouth. Voila. Two days later, you’ve got a fever. Research suggests it's no coincidence: A 2012 study published in the journal Proceedings of the National Academy of Sciences showed that people who reported being stressed out were twice as likely to get sick compared to their less-stressed counterparts.

If you’re otherwise healthy and managing stress well, you can recover relatively quickly from the common cold or flu, but that doesn’t mean it won’t sideline you from some of the festivities you had planned. And if you’re exposed to chronically high stress levels— say, ahem, from Thanksgiving to New Year’s Day— your immune system is further thrown out of whack, leaving you vulnerable to more serious health problems. Chronically high levels of cortisol dial up inflammation in your body that promotes disease, such as cardiovascular and autoimmune disorders. Not exactly the Christmas gifts you were hoping for.

You can’t afford to be slowed down this time of year— and no one wants to be sick in bed watching the ball drop. The good news is that by regulating your stress and how you respond to it, you can boost your immunity and lower your cortisol levels.

Here are my top holiday stress survival tips to keep you merry and healthy all season long:

Prepare your immune system

During the winter, you’re out and about shopping among crowds of people, and you’re indoors more often. This double-whammy can run you ragged while exposing you to strangers’ germs. Keep your vitamin D levels up by supplementing your diet with 2000 IU each day— according to the National Institutes of Health (NIH), it plays a vital role in positive immune response. Vitamin C is another great supplement to keep on hand. Whether the vitamin provides immunity from the common cold is still unclear, but at least one study suggests it can shorten the illness if you’re already sick.

Resist sugar’s siren song

Visions of candy canes and sugar plums dancing in your head may conjure warm feelings, but the sugar they contain actually inhibits phagocytosis, a process by which the body uses white blood cells to attack foreign invaders. To give your immune system a fighting chance, steer clear of cakes and cookies, gingerbread or otherwise, at the office— and be sure to fill up on healthy sources of protein that will keep you full. Science also suggests that people with pre-diabetes and diabetes— which impairs the body’s ability to properly metabolize sugar— get sick more frequently. Because I have a family history of diabetes, I get my levels checked often. Ask your doctor to test your hemoglobin a1c, which shows how much sugar has been in your blood over the last three months. You want a maximum level of 5.5— higher than that, and you’ll really have to restrict the sweet treats.

Don’t lose sight of yourself this season

The very time you’re most likely to let self-care slip is when you need to prioritize it the most. Even if you can’t squeeze in a massage or a regular yoga class, you can give yourself the gift of daily, mini self-care practices, which will increase your ability to crank out your to-do list despite tacking on time to your already seemingly full schedule. Eat breakfast every day, keep hydrated on runs to the mall (or just shop from the comfort of your own home!), and don’t underestimate how much energy and time goes into holiday travel and other commitments. In fact, assume they will take longer than you expect and under-book yourself. It will be the gift that keeps on giving! Remember, your holidays don’t have to be picture- perfect to be joyful. The most important precursor to spreading good cheer is feeling well inside and out.

Dr. Jennifer Landa is Chief Medical Officer of BodyLogicMD, the nation's largest franchise of physicians specializing in bioidentical hormone therapy. Dr. Jen spent 10 years as a traditional OB-GYN, and then became board-certified in regenerative medicine, with an emphasis on bio-identical hormones, preventative medicine and nutrition. She is the author of "The Sex Drive Solution for Women."  Learn more about her programs at www.jenlandamd.com