Fun summer activities may be just what the doctor ordered to keep your immune system strong. An immune system running at peak efficiency can help reduce allergy symptoms and prevent summer colds.

How does one bolster immunity if you are an allergy sufferer? Turns out some of your favorite summer activities/foods/fun may offer ways to rev up your immune system.

Get out in the sun

An increase in cases of Vitamin D deficiency over the past several decades is thought to be one of the reasons that allergies and asthma have been increasing. What is different now than 50 years ago? We spend much less time outdoors, decreasing the Vitamin D made in our skin.

Get a healthy dose of Vitamin D by spending some time outside every day in the summer sun. Take a stroll during your lunch break, go on a walk with Fido or work in the garden. Summer is a great time to stock up on Vitamin D. Ten minutes in the midday sun—in shorts and a tank top with no sunscreen—will give you enough radiation to produce about 10,000 international units of the vitamin.

Enjoy a cup of froyo

Refrigerated yogurt is a great source of live bacteria, beneficial for your digestive system, where the majority of your immune system resides. But what about frozen yogurt (froyo), a tasty summer time treat. Froyo is just as healthy as refrigerated yogurt. In fact, the University of Michigan Health System explains that the probiotics within yogurt are able to survive the freezing process without altering the health benefits. So, have a cup of froyo and give your body a healthy treat.

Sip your favorite iced tea

A tall glass of iced tea on a hot day is refreshing, and it might also do your body good. Compounds in black and green tea can power up your immune system. How? Tea is rich in a class of antioxidants called flavonoids, which are most potent when tea is freshly brewed. If you want to keep a batch of cold tea in your refrigerator, add a little lemon juice. The citric acid and vitamin C in that squeeze of lemon—or lime, or orange—help preserve the flavonoids.

Visit the farmers’ market

Fruit and veggies seem to rev up your immune system. Wander around the farmers’ market to get some local, fresh produce and soak up some healthy sunshine as well. The fiber produce contains also will feed good bacteria in your digestive system.

Enjoy outdoor activities

Activities you enjoy bolster immunity by reducing levels of immune weakening stress hormones. Go to Shakespeare in the park, have a picnic in the park, take a hike in the foothills, paddle around a lake.

Relax

Serious R&R busts stress, which wears down your immune system.