Get access to everything we publish when you sign up for Outside+.
1. Turn Down The Heat
If just the thought of leaving the warmth of your cozy home in winter gives you the shivers, think again. In one study, participants who were dunked in cold water three times a week for six weeks showed signs of improving immunity. Scientists reporting their findings in the European Journal of Applied Physiology and Occupational Physiology theorize that shivering increases metabolic rate enough to activate the immune system slightly.
TRY: Reprogram your thermostat and spend the savings on a cozy new blanket for when you really need to warm up. Or brave a cold water bath once a week.
2. Say Yes to Carbs
We’re not talking bingeing on comfort foods like creamy mac ’n’ cheese and cookie dough ice cream. But tucking into a bowl of oatmeal or stirring up a pot of split pea soup not only feels good this time of year, it’s also good for your immune system. These fiber-rich foods have something called “microbiota-accessible carbohydrates,” which, as an August 2014 report in Cell Metabolism reveals, are largely missing from Western diets, triggering immune dysregulation and disease.
TRY: Aim for the daily recommendation of 21 to 38 grams of fiber (depending on your age and gender). One cup of lentils has a whopping 16 grams, while cooked black beans are a close second, with 15 grams per cup.
3. Eat & Exercise Lightly
See one neighbor sprinting his way through a 10K while another binges on Seinfeld reruns on the couch? They’re both compromising their immune systems. But by going for an easy jog or a brisk hike, you can reduce your incidence of infection, according to a review of studies published in the Journal of Applied Physiology. Workouts lasting longer than 90 minutes and requiring 55 to 75% of your maximum effort tend to suppress immunity, researchers found.
TRY: Sign up for your local long-distance run, but take it at a leisurely pace. And eat a small snack before, during or immediately after prolonged exercise, as the study subjects with reduced immune systems had no food before their hard workouts.
4. Add the Color Red to Your Diet
Summer may be the season for heirloom tomatoes, but winter’s when their antioxidant compound, lycopene, can really help keep you healthy. As the American Cancer Society reports, people who have diets rich in tomatoes have been scientifically shown to have a lower risk of certain types of cancers, and lycopene may also reduce inflammation and LDL (“bad”) cholesterol while boosting the body’s defenses.
TRY: Try to consume 10,000 mcg of lycopene per day, the amount recommended by Dr. Edward Giovannucci, professor of nutrition and epidemiology at Harvard School of Public Health. That’s less than a half-cup of tomato purée or one piece of watermelon, or a grapefruit plus a half-cup of marinara sauce.
5. Have a laugh
Remember the movie Patch Adams? The doc had it right: humor can actually heal.
As the American Cancer Society explains, laughter increases your breathing rate and oxygen use while sparking beneficial short-term changes in hormone levels and certain neurotransmitters. The result? A stimulated immune system to battle sickness.