Ways to Boost Your Immune System

Now, more than ever, it is especially important for us to find ways to help support our immune system. Below are some well-known, and maybe not-so-well-known strategies for boosting immune system function.



There is extensive research connecting sleep and immune function. Sleep has been shown to enhance your body’s immune function and boosting the body’s ability to fight foreign invaders. Acute and chronic sleep deprivation can lead to chronic inflammation in the body which is linked to metabolic and cardiovascular disorders.

During sleep, your body produces cytokines that support immune function and target infections. If you’re lacking in sleep, you’re going to be missing these important immune-boosting cytokines and thus, leaving yourself vulnerable to infections. Additionally, stress-response hormones are reduced during sleep, including cortisol, epinephrine, and norepinephrine. Conversely, drivers of cell growth and restoration, such as growth hormone and melatonin, are increased while you sleep.

Cortisol is an essential hormone to our survival, but chronic, elevated levels of cortisol can lead to health problems, including hypertension, diabetes, heart disease, obesity, mood disorders, among others. Chronic stress can lead to sustained, elevated cortisol levels which can lead to sleep deprivation and reduced immune function, increased systemic inflammation, and chronic disease. Additionally, poor sleep quality, quantity, and inconsistency in sleep schedules can lead to elevated cortisol levels.

Growth Hormone (GH) is an important player in the immune system function. The majority of GH is secreted while we sleep, and it plays a role in stimulating the production of immune cells. Deficiencies in GH can lead to impaired growth, body composition, and metabolism, along with impaired immune system functioning.

According to the National Sleep Foundation, adults (age 18-64 years) should shoot for an average of 7-9 hours of sleep each night. They recommend that teenagers get roughly 8-10 hours per night, and older adults (65+ years) should get between 7-8 hours of sleep per night.



Vitamin D has been shown to play a role in essential immune system function and therefore, a deficiency in the vitamin may result in impaired immune responses and auto-immune disorder development.

No consensus has been reached regarding recommended daily intake for vitamin D and the establishment of a safe upper limit for supplementation. The Endocrine Society guidelines advise a safe upper limit

for daily intake at 10,000 IU. The US Institute of Medicine, on the other hand, advises an upper limit of 4,000 IU/day.

Other sources of Vitamin D are sunlight (UVB) exposure and diet. For humans, vitamin D is mainly synthesized after exposure to sunlight (UVB) in the skin. Some vitamin D can also come from the diet such as from fish and certain mushrooms. More commonly, foods are fortified with vitamin D, as is seen with dairy products in the US.



Vitamin C supplementation has been shown to have positive effects on our immune system, through processes including antimicrobial activities, antioxidant properties, and inflammatory mediation. Additionally, vitamin C functions to assist in collagen production, contributing to the quality and maintenance of tissues throughout the body. Vitamin C is a powerful antioxidant and research has shown that it can effectively protect against some chronic and acute diseases.

The US Institute of Medicine established a recommended daily intake of 75 mg for women and 90 mg for men. However, recent research may suggest that higher doses of vitamin C, up to 200mg/day, may provide additional benefits.

Roughly 90% of our daily intake of vitamin C comes from fruits and vegetables. Citrus fruits and vegetables including broccoli, tomatoes, and peppers are great vitamin C sources. It should be noted that vitamin C breaks down under heat and with storage, so eating fresh, raw fruits and vegetables will maximize the quality of your vitamin C intake. To get approximately 200mg of vitamin C, you will want to consume 5-9 servings of fresh fruits and vegetables, daily.



Exercise can have a negative or positive impact on immune function, depending on the frequency and intensity of the exercise! Prolonged periods of high-intensity exercise can reduce immune function, while regular, moderate-intensity training can enhance your immune system.

Regular, moderate exercise provides enhanced immune system function possibly due to its anti-inflammatory effects, alterations in immune cell composition, improved immunosurveillance, and positive effects of exercise on psychological stress management.

Get in moderate exercise at least 3 times per week, for at least 30 minutes at a time. Incorporate both resistance training and cardio exercise into your regular routine.

Kelly Wild (@kellywild8) is a licensed Doctor of Physical Therapy. She also is a National level Olympic Weightlifter and former 3 time CrossFit Games athlete. Kelly also played Division I ice hockey at The Ohio State University. Kelly believes that health care should be proactive, not reactive. This mantra has inspired Kelly to publish a number of online fitness protocols at Californiastrength.com that anyone can use to reduce injury risk and improve strength in order to continue to pursue all of your athletic and fitness goals!