Frequent colds, infections, and fatigue are signs you may have a low immune system - here's when to see a doctor

Tabitha Britt,Jason McKnight

Jan 15, 2021, 22:50 IST

Frequent colds, infections, and fatigue are signs you may have a low immune system - here's when to see a doctor

Symptoms of a low immune system include fatigue, frequent colds, and increased stress levels.Roos Koole/Getty Images

A low immune system can be caused by a number of factors including, diet, certain medications, infections, or having an autoimmune disorder.
If you're having frequent colds, difficulty fighting off infections, persistent fatigue, or digestive issues, you may have a weakened immune system.
Eating a balanced diet, getting plenty of sleep, and exercising regularly may help strengthen your immune system.

There are many reasons why you might have a weakened immune system. Some you can control, such as your diet, stress levels, and the amount of sleep you get. If you're immunocompromised or required to take certain medications (like chemotherapy drugs), however, you may have less control over your immune system.

According to the Bulletin of Atomic Scientists, there are an estimated 10 million people living with a compromised immune system in the United States.

"There's no magic pill for improving the immune system," says Abisola Olulade, MD, a board-certified family medicine physician. Instead, Olulade says limiting your alcohol intake, getting plenty of exercise, an adequate amount of sleep, and lifestyle choices such as avoiding smoking, is the key to maintaining a healthy immune system.

Here's what it means to have a low immune system, how to spot the signs and symptoms of a weakened immune system, and how to implement positive changes into your everyday routine.

What are the signs of a weak immune system?

"There are certain telltale signs of weakened immunity," says Olulade. "If you keep getting infections, if it takes you longer to get better from infections, or if your wounds take longer to heal, you may have a weakened immune system."

Signs and symptoms of a potentially low or weakened immune system include:

Constant cold. Experiencing two-to-three colds per year is normal, but if you find that you're catching colds frequently, it could be a sign that your immune system could use some support.
Frequent infections. Individuals with a weak immune system tend to get pneumonia, bronchitis, and meningitis, among other infections often.
Fatigue or exhaustion. Sure, everyone feels a bit lazy from time to time, but if you find that you're struggling to stay awake, your immune system may be compromised. This is because sleep and the immune system have a "bidirectional relationship" - being sick or having a viral infection can negatively impact your sleep whereas consistent sleep can strengthen the immune system.

Increased stress levels. According to the American Psychological Association, long-term stress and loneliness can have a negative impact on your immune system. This is because stress lowers your lymphocyte levels, making it harder for your body to fight off infection. So if you tend to get sick following an exam or big project at work, you may want to consider implementing stress management into your daily routine.
Digestive issues. Diarrhea, gas, bloating, cramping, and even constipation could be a sign that your immune system isn't working properly. When the "good" gut bacteria (probiotics lactobacilli and bifidobacteria) goes awol, your immune system takes a hit.

The good news is that your doctor can check your immune system with a series of blood tests.

"You can check your immune system by having blood tests that tell you if you have sufficient levels of antibodies like immunoglobulin, white blood cells, platelets, and immune system cells," says Alex Ruani, a doctoral researcher in nutrition science education.

What causes a low immune system?

Common causes of a weakened immune system include:

Smoking
Alcohol
Poor nutrition
Medication like chemotherapy or other cancer treatments
Infections like. the flu, mono, and measles
Autoimmune disorder
HIV or AIDS

When your immune system isn't working as it should, doctors may tell you that you have an "immune system disorder" - meaning you may have one or more of the following conditions:

Immune deficiency. Immune deficiency is something that you're born with. This is known as a "primary immunodeficiency disease" (PIDD). PIDDs are genetic disorders that may damage the immune system or cause it to malfunction. Though rare, PIDDs affect approximately 500,000 people in the US.

Acquired immune deficiency. HIV, which causes AIDS, is an acquired viral infection that demolishes the body's white blood cells and weakens the immune system. Individuals who have HIV/AIDS have more difficulty fighting off diseases/infections, especially if they aren't getting treatment.

Overactive immune system. When an immune system is hyperactive, it responds to environmental substances such as mold, dust, and pollen.

Autoimmune disease. When you have an autoimmune disease your body is unable to distinguish the difference between your own cells and foreign cells (or potentially harmful antigens), causing the immune system to work against itself. There are more than 80 types of autoimmune disorders, including but not limited to type 1 diabetes, lupus, celiac disease and rheumatoid arthritis.

How do you fix a low immune system?

Although there's still research to be done, exercise, diet, and psychological stress have been proven to affect the immune system. For immunocompromised individuals, improving the immune system isn't as simple. Depending on why you're immunocompromised, a weakened immune system could be permanent.

If you're immunocompetent (aka you have a working immune system), here are a few things you can do to get your immune system in gear.

Eat a balanced diet. Incorporating more fruits and veggies, fiber-rich foods, prebiotics (garlic, onions, leeks, etc.), and probiotics (kefir, yogurt, kombucha tea, etc.) into your diet could help you boost your immune system.

"Specific foods or supplements cannot make us immune," says Ruani. "But a nutritious diet that includes all essential nutrients in sufficient quantities can help."

To ensure you're doing all that you can to boost your immune system, you should eat plenty of:

Citrus fruits (oranges, grapefruit, and lemons)
Leafy greens (spinach, kale, and collards)
Red bell peppers
Yogurt
Ginger

"Besides fiber, prebiotics, and probiotics, to support immune function we also need adequate protein, fiber, omega 3 fats, vitamins D, C, B, A, E, and K, and minerals like iron, calcium, selenium, and zinc," says Ruani.

Get an adequate amount of sleep. When you're asleep, your body unleashes its healing powers - aka protective cytokines. Protective c ytokines are proteins that are released during sleep to help your body do two things: Encourage sleep and fight off infection. Sleep deprivation reduces the number of protective cytokines your body produces, making it harder for it to fight off infection.

Stress management. If not managed, stress can wreak havoc on your health. Stress can affect your body, mood, and behavior.

"Chronic, elevated levels of stress hormones like cortisol, adrenaline, and noradrenaline can be immunosuppressive, which means this can diminish infection-fighting responses while increasing inflammation in the body," says Ruani.

Effective stress relievers include:

Exercise
Meditation or yoga
Laughing
Journaling

Practice good personal hygiene. The best way to keep your immune system intact is to start at the source: Your body. By following good personal hygiene habits, you can stop an infection before it begins.

Good personal hygiene practices include:

Washing your hands regularly (before preparing food, after using the toilet, etc.)
Covering your mouth when you cough
Keeping wounds, cuts, and scrapes clean and bandaged

Exercise regularly. In addition to keeping your bones strong and healthy, research shows that physical activity has the potential to flush bacteria out of the lungs and airways (reducing your chances of getting a cold or the flu) and decreases your chances of developing heart disease.

Insider's takeaway

In the end, there's no one answer to "fixing" your immune system. However, there are ways to support it, including maintaining a healthy and active lifestyle, eating nutritious foods, and ensuring that you're getting plenty of sleep.

"Don't rely on supplements," says Olulade. "Get vaccinated, exercise, sleep, eat a healthy diet, go in for checkups with your doctor so that chronic conditions can be detected, limit your alcohol intake, and practice good personal hygiene (including safe-sex practices). All of these things can help to maintain a healthy immune system."