Infectious diseases have been plaguing humans for thousands of years. Since then, people have experienced a variety of illnesses—ranging from minor to complicated to chronic and life-threatening—which are all crucial to their mortality.  As humans evolved, so did bacteria and other disease-causing organisms (pathogens).  

These pathogens are almost everywhere and have different ways of transmission, including skin contact, bodily fluids, airborne particles, and ingestion of contaminated food. Even touching a surface touched by an infected person can cause the spread of disease. But have you wondered why you do not always get sick?

It is because of a healthy immune system.

The immune system is responsible for defending the body from the invasion of harmful pathogens. You need your immune system to remain healthy, because a weak immune system puts you at a higher risk of experiencing frequent infections and severe symptoms.    

Due to the COVID-19 pandemic, many people are now paying closer attention to ways that they can strengthen and maintain a healthy immune system. Diet and lifestyle have more to do with it than you think.

Here are seven lifestyle tips to help improve your immune system:

1. Get Enough Sleep

Not that you need another reason for getting enough rest, but there are several studies linking sleep and immunity. Your body heals and regenerates while you sleep—increasing your protection from various illnesses. Therefore, adequate sleep is critical for a healthy immune response. 

During sleep, your immune system regulates specific immune cells and molecules like cytokines (a type of protein that prevents or promotes inflammation), interleukin 12 (a pro-inflammatory cytokine that regulates allergic inflammation), and T cells (a type of white blood cell that regulates immune response). Altogether, they strengthen your body’s immunity. 

When you do not get enough sleep, the production of these infection-fighting antibodies decreases, making you more vulnerable to infection and increasing your likelihood of getting sick.

One study found that when you sleep fewer than 6 hours each night, you are more likely to catch a cold than when you sleep for 6 hours or more each night. Another study suggests that getting adequate rest when sick allows your immune system to better fight the illness. 

Interestingly, a 2010 study claims that oversleeping can be as hazardous as sleep deprivation. Researchers found that sleeping beyond 10 hours per night is associated with a greater risk of death. However, the study had several limitations and requires further clarification.

Nonetheless, adequate sleep comes with many benefits. As per recommendation, all adults should get at least 7 hours of sleep each night, while teens need 8-10 hours to optimize health. 

RELATED: Insomnia: Why Getting Poor Sleep Is Cause for Alarm

2. Engage in Physical Activity 

While it’s important to rest your body and sleep adequately at night, so is having regular exercise by day. Engaging in physical activity has a lot of benefits to your health, including your immune system. A 2018 review published in Frontiers of Immunology found that adequate physical activity lowers the risks of chronic diseases (like obesity, heart disease, and type 2 diabetes) and viral and bacterial infections. 

Furthermore, engaging in physical activities can also help manage stress by releasing more endorphins (a group of hormones that relieve pain and create feelings of pleasure). And when you reduce your stress levels, it can have a positive impact on your immune system. Likewise, lack of physical activity makes you vulnerable to diseases and infection—including severe COVID-19 outcomes.

And while very long or intense exercise may suppress your immune system, several epidemiological evidence proves that moderate exercise can give it a boost. What’s more, regular moderate-intensity exercise can reduce inflammation and help regenerate your immune cells. 

The Centers for Disease Control and Prevention (CDC) outlines physical activity guidelines for all age groups. At a minimum, adults should have 150 minutes a week of moderate-intensity aerobic activity. For example, you could do brisk walking for 30 minutes, five days a week. And for the other two days, you could do muscle-strengthening activities that work all major muscle groups (legs, hips, back, abdomen, chest, shoulders, and arm). 

RELATED: The Health Impacts of a Sedentary Lifestyle: Problems and Solutions

3. Eat More Healthy Foods

Eating nutritious foods — in particular, plant-based foods like fruits, vegetables, nuts, seeds, and legumes — is part of leading a healthy lifestyle. Coincidentally, these foods are rich in antioxidants that may give you an advantage against harmful pathogens. Moreover, the antioxidants in these foods are responsible for resisting unstable compounds (free radicals) that can cause inflammation. 

In other words, the consumption of plant-based foods helps reduce inflammation in your body. This benefit is crucial because chronic inflammation can cause numerous health conditions, including arthritis, diabetes, heart disease, and certain cancers. 

A plant-based diet also improves immunity by strengthening the community of healthy bacteria (microbiome) in your gut. The fiber in plant foods nourishes your gut microbiome, which helps keep harmful pathogens from entering your body through your digestive tract. 

Meanwhile, the vitamin C (ascorbic acid) you get from fruits and vegetables may help reduce the duration and severity of common colds. 

RELATED: Going Vegan: Benefits of a Plant-Based Diet

4. Staying Hydrated and the Immune System

Proper hydration is essential in maintaining a healthy immune system. Its purpose is not necessarily to protect you from bacteria and viruses but to prevent dehydration. Because when you’re dehydrated, it causes several adverse effects on your body, including headaches, complications in digestion, heart and kidney function, and limitations in physical performance. As a result, they can compromise your immune system and increase your susceptibility to illness.

Good hydration means you drink enough water—and not just any liquid. While other beverages and foods can help with hydration, it’s best to drink plain water because it’s free of calories, additives, and sugar. Much evidence suggests that a higher intake of sugar-sweetened beverages increases the risk of weight gain and obesity. 

The rule of thumb for adequate hydration is to drink water when thirsty. But an average adult should have a daily fluid intake of 9 -13 cups as per the Institute of Medicine’s (IOM) recommendation. 

It’s also worth noting that your sensation for thirst decreases with age. Older adults have a higher risk for dehydration since they begin to lose the urge to drink. For this reason, they should continue to drink plenty of water even when they don’t feel thirsty. 

RELATED: Good Hydration: Water as Therapy

5. Avoid Alcohol, Cigarettes, and Other Substance Use

Alcohol

Alcohol is not the best way to stay hydrated or cope with stress. Aside from developing dependence, frequent consumption can cause a lowered immune response. Several studies suggest that people with alcohol dependence have a higher risk of infection—especially pneumonia. 

A 2017 study found that chronic heavy alcohol use can lower lymphocyte (b cells and t cells) numbers, which play a significant role in your ability to fight infection and improve your recovery time. As a result, heavy alcohol drinkers are more likely to get bacterial and viral infections — not to mention an increased incidence of Mycobacterium tuberculosis. 

Furthermore, excess alcohol can fuel disease progression in chronic viral infections such as human immunodeficiency virus (HIV) and Hepatitis C. Another 2015 review in Alcohol Research has linked alcohol consumption to pulmonary diseases (i.e., acute respiratory distress syndrome), alcoholic liver disease, and certain cancers. With the abundance of evidence, it is clear that alcohol use involves a wide range of risk that threatens your health.

The CDC recommends limiting your alcohol consumption to two drinks (equivalent to an 8-ounce glass of wine) or less per day for a man and one drink per day for a woman. But even then, if you do not want to compromise your health and immunity, it is best to avoid it entirely.  

Cigarette Smoking

Meanwhile, like alcohol, cigarette smoking also compromises your immune health. According to a review published in Oncotarget, smoking tobacco releases chemicals — nicotine, carbon monoxide, nitrogen oxide, and cadmium — that interfere with the growth and function of immune cells, thereby increasing your susceptibility to illness. 

In addition, the CDC also suggests that smoking can cause or worsen the following diseases:

• Rheumatoid arthritis (an autoimmune disease that causes the joints to swell and be painful);
• Viral and bacterial infections (especially of the lungs like pneumonia, influenza, and tuberculosis);
• Bacterial meningitis (a disease of the brain and spinal cord); 
• Post-surgical infections; and
• cancer

It cannot be stressed enough how dangerous cigarette smoking is to your health. If you want to quit smoking, many available resources can help you, including counseling, nicotine replacement products, and behavioral therapy.

RELATED: Alcohol: The World’s Most Harmful Drug

6. Manage Your Stress Levels

We all experience pressure and have to deal with stress. Some can handle it well, while others struggle with it. Stress prompts the body to release the hormone cortisol. The body requires it to limit inflammation and conduct its response to a stressor. However, too much cortisol leads to the increased production of inflammatory cytokines that reduce the immune system’s effectiveness.

Indirectly, stress can also affect the immune system by precipitating an individual to use unhealthy coping behaviors, such as smoking, drinking alcohol to excess, poor diet and lack of exercise due to time constraints, and lack of sleep. All these bad habits can negatively impact immunity. 

If you want to keep away from illness and infection, you must learn to manage your stress levels. While there are many effective stress-reduction techniques, finding what works for you is essential. To give you an idea, here are a few options for reducing stress:

• Accept your needs and identify what triggers your anxiety;
• Manage your time and prioritize your activities;
• Practice relaxation such as deep breathing, meditation, and progressive muscle relaxation;
• Avoid alcohol and drugs; 
• Take time for yourself and enjoy; and
• Talk to friends, family, a counselor, or a support group (NAMI Connection). 

Aside from the list above, there are many more stress-reducing activities for you to consider. Try doing at least one of them every day. 

RELATED: Posttraumatic Stress Disorder and the Rise of Chronic Diseases

7. Practice Proper Hygiene

While practicing proper personal hygiene does not directly boost your immune system, it is critical in preventing the spread of germs, including the virus that causes COVID-19. Reduce your exposure to harmful pathogens by practicing basic habits like washing your hands, using hand sanitizers, and distancing yourself from sick or infected people.

A 2020 study published in the Journal of Advanced Oral Research has found that hand sanitizers containing at least 60% alcohol can kill germs but are not as effective as washing your hands with soap and water. Make it a habit to carry a hand sanitizer with you in public and use it when soap and water are not accessible. 

Some people continue to wear masks in public places even when restrictions have loosened. They may be concerned about their immune status and would like to prevent taking a chance. It is conceivable that wearing masks during the peak of cold and flu season may become a regular practice. Physics of Fluid published a review about face mask materials and found that a stitched face mask made of cotton quilting consisting of 70 threads per inch was the most effective in preventing the spread of droplets (respiratory particles that could contain a virus). 

Nevertheless, don’t forget to cover your nose and mouth every time you cough or sneeze to prevent infecting the people around you (but not with your hand!).

Conclusion

It’s been more than two years since the pandemic began, but it does not seem to be ending anytime soon. The active cases have started to decrease since the introduction of vaccines, but we still need to do our part to strengthen our immune system. It is a powerful defense against potential pathogens that could harm the body. That is why you need to keep it healthy to optimize its function. 

A healthy lifestyle supports immunity. Exercising regularly, getting adequate sleep, staying hydrated, and managing your stress levels, among others, are all crucial to effectively fight against infections and diseases. 

While following these lifestyle tips will not guarantee absolute protection from viruses or a more severe COVID-19 infection, they can help improve the chances. 

Remember, staying healthy is a decision all of us can make every day. What you decide now will determine what your future will be.