Traditionally, people primarily focused on the health of their immune system during cold and flu season or if they were managing a chronic illness. Today, year-round immunity is now top of mind for many people. Adopting a regular exercise program is an enjoyable and simple way to enhance your defenses.

Did you know? Your immune system tends to be more susceptible to inflammation during the winter months. That may be why the risk for heart conditions, psychiatric issues, and autoimmune diseases are also higher in the winter. (8)

A daily sweat session provides your immune system with a host of benefits that can help you stay healthy all year long.

The health benefits of exercise for immune function

How does exercise boost your immune system? Studies show that regular moderate workouts can benefit the immune system in the following ways:

· Briefly elevates body temperature, which may prevent bacteria from growing (10)

· Enhances the body’s response to vaccines (25)

· Increases the circulation of infection-fighting antibodies (10)

· Lengthens telomeres, which are sections of DNA at the end of chromosomes that protect your chromosomes from deterioration (27)

· Lowers total white blood cell, neutrophil, and monocyte counts; high levels of these immune cells can indicate an infection or an immune system disorder (17)

· May flush bacteria out or the lungs and airways (10)

· Mobilizes key immune cells including T-cells and natural killer (NK) cells (25)

· Reduces inflammation, which can lower the risk of respiratory infection (22)

· Slows down the release of the stress hormone cortisol as chronically high cortisol levels can compromise the immune system (10)

Exercise also improves immune system activity in older individuals. As we get older, our immune cells don’t function as effectively as they once did, leaving us more vulnerable to infection, autoimmune problems, metabolic conditions, osteoporosis, and neurological diseases. (2) Studies comparing sedentary seniors with those participating in regular exercise have found that older people who worked out had considerably better immune function and a lower risk of infection and chronic illness. (25)(28)

Did you know? Exercise is so effective for enhancing immunity that some scientists believe it should be considered a drug. (29)

Exercise can help counteract the effects of aging on your immune cells.

Best types of exercise for your immune system

Exercise can include a variety of activities, but typically most of these activities fall into three categories: aerobic, resistance, or balance/stretching. Each type of exercise has unique benefits for your immune system.

Aerobic exercise

Aerobic workouts increase circulation and reduce pro-inflammatory compounds in the body. (18)(30) Aerobic exercise also increases body temperature, helping kill off harmful bacteria. (11) Even something as simple as walking can increase the number of infection-fighting leukocytes in the bloodstream. A brisk stroll can also increase neutrophils and NK cells while reducing immune-suppressing adrenaline cortisol levels. (2) Some examples of aerobic exercise include:

· Biking

· Dancing

· Cross-country skiing

· Exercising on a stair-climber or elliptical machine

· Hiking

· Jogging

· In-line skating

· Kickboxing

· Rowing

· Running

· Swimming

· Walking

Resistance exercise

Also known as strength training, resistance exercise builds muscle, which increases the amount of glutamine your body produces. (24) Glutamine is an amino acid that supports the division of immune cells when your body encounters pathogens. It also helps macrophages and neutrophils produce compounds that destroy harmful bacteria and viruses. (5) Activities considered to provide resistance include:

· Body weight exercises (e.g., pushups, pullups)

· Resistance bands

· Suspension training

· Weightlifting using free weights

· Weight machines

Flexibility/balance exercise

These activities typically employ deep breathing, which has been shown to support a healthy lymphatic system, a system made up of glands that filter and destroy foreign contaminants, produce antibodies, and create more lymphatic cells. (9) Studies also report that these exercise modalities reduce inflammation and lower immune-dampening stress. (7)(16) Examples of flexibility/balance exercises include:

· Qigong

· Stretching

· Tai Chi

· Yoga

How much exercise do I need?

For those just starting out on their fitness journey, it’s often difficult to determine just how much exercise you should be getting. According to the Centers for Disease Control and Prevention (CDC), adults should get at least 150 minutes of moderate exercise or 75 minutes of vigorous exercise each week. (14) While that may sound like a lot to people who aren’t used to exercising, it breaks down to just 30 minutes of moderate exercise or a minimum of 15 to 30 minutes of vigorous exercise per day, five days per week. If you’re not used to working out, be sure to build up your stamina slowly. It’s also important to check in with your health care professional before you begin an exercise regimen, especially if you suffer from a chronic condition like cardiovascular disease. (19)

Is too much exercise bad for your immune system?

When it comes to incorporating physical activity into your lifestyle, the CDC notes that more is better. (14) The goal is to get your body moving and to work out hard enough to raise your heart rate. But can you overdo it? For years, studies posited that exercising too intensely or for too long could suppress your immune system. (1)(13)(21) However, more recent research has debunked that theory. A 2018 study conducted at the University of Bath took a closer look at the validity of the evidence presented in these earlier studies, noting that regular, long-term exercise—even intense exercise—helps the immune system find and neutralize pathogens that can cause infection. The study authors conclude that factors like poor diet, stress, or insufficient sleep likely play a larger role in an athlete’s vulnerability to infection than the act of exercise itself. (6)

Did you know? Examples of intense exercise include training for and participating in activities like marathons, triathlons, or powerlifting.

Feeling under the weather? Skip your workout if you have a fever, chest congestion, or gastrointestinal symptoms.

Can I exercise when I’m sick?

It depends. If your symptoms include nasal congestion, runny nose, sneezing, sore throat, or a mild headache, studies suggest that you can exercise, although you may want to reduce the intensity of your workout. It’s also wise to skip the gym or other crowded workout space to prevent sharing your illness with others. On the flip side, if you suffer from a fever, aches, chest congestion, stomach cramps, or vomiting, take a break. (15) Resume your normal workout gradually as you begin to feel better.

The bottom line

Adding exercise to your daily routine can enhance your immune system throughout the year. While it’s beneficial to incorporate a variety of aerobic, resistance, and flexibility workouts into your fitness plan, the most important thing is to find a least a couple of activities you enjoy. This can encourage you to stick to a regular exercise program. Another tip? Find a workout buddy or sign up for an exercise class to help you stay accountable to your fitness goals. Making exercise a lifelong priority not only helps prevent seasonal illness, it also promotes healthy aging—and that’s a pretty sweet payoff.