The immune system is the body’s defense against harmful germs and infections. It also responds to physical injuries, helping to heal wounds and repair tissue.

The immune system contains specialized cells and proteins that help fight threats like disease-causing bacteria and viruses. Practicing healthy habits can help keep your immune system strong—preventing illness and speeding up recovery when you do get sick.

Your body repairs itself while you sleep. During deep sleep, your immune system produces proteins called cytokines, which help fight infections and inflammation. Studies show that people who don’t sleep enough are more likely to get sick after exposure to viruses like the common cold.

Here are a few tips for getting better sleep:

• Go to bed and wake up at the same time every day, even on weekends
• Aim to sleep for at least seven hours per night; if needed, take short naps to recharge
• Avoid phones, TVs, and computers at least an hour before bed
• Create a relaxing bedtime routine, like reading a book, taking a warm bath, or listening to calming music
• Make your room sleep-friendly; keep it cool, dark, and quiet
• Avoid alcohol and too much caffeine close to bedtime

Regular exercise and outdoor light exposure during the day can also help regulate your sleep cycle.

Research is ongoing, but exercise may help strengthen the immune system. Physical activity might help clear bacteria from the lungs and airways, reducing the risk of infections like colds and the flu. Exercise also causes disease-fighting white blood cells to circulate more quickly, possibly allowing the body to detect illnesses earlier.

The temporary rise in body temperature during exercise may also help fight infections, similar to how a fever works. While regular exercise can support immunity, too much intense exercise—like marathon training—can weaken the immune system.

Here are a few tips for getting enough exercise:

• Find an activity you enjoy: Walking, dancing, yoga, or biking are great options.
• Aim for 30 minutes a day: Even small amounts of movement can help you reach your goal.
• Don’t overdo it: Too much intense exercise can weaken your immune system temporarily.

Staying hydrated is essential for a strong immune system, as water helps the body fight infections and recover from illnesses. Dehydration can weaken immune function by disrupting fluid balance and reducing the ability of immune cells to communicate and respond to threats.

Proper hydration also helps regulate body temperature and supports the movement of essential nutrients that aid in immune defense. Drinking enough water, along with getting key vitamins and minerals, can help prevent illness and speed up recovery when sick.

Here are a few ways to stay hydrated throughout the day:

• Carry a water bottle with you and sip throughout the day
• Drink water with meals instead of sugary drinks
• Choose low-calorie beverages like plain tea, coffee, or sparkling water
• Eat hydrating foods, like fruits and vegetables
• Increase water intake during hot weather or exercise to replace lost fluids
• Watch for signs of dehydration like dark urine, dry mouth, or headaches
• Set a goal, like drinking a liter of water by midday, to stay on track

Too much sugar can weaken immune cells, making it harder for them to attack harmful bacteria and viruses. High sugar intake has been linked to increased inflammation and a higher risk of infections.

Eating too much sugar can also weaken the immune system by disrupting the balance of good bacteria in the gut, replacing beneficial bacteria with harmful bacteria that lower protective immune responses.

A few ways to reduce your sugar intake include:

• Choose whole foods: Eat fresh fruits, vegetables, and lean proteins
• Read food labels: Avoid processed foods with added sugars
• Limit sugary drinks: Swap soda and juice for water or herbal tea

Talk with your healthcare provider about ways you can reduce your sugar intake and stick to a nutritious diet that is right for you.

Stress increases cortisol levels, which may weaken the immune system. Some evidence shows very high cortisol levels can suppress immune cell activity and make the body more vulnerable to infections.

While short-term stress can temporarily boost immunity, long-term stress disrupts immune function and increases the risk of illness. Effectively managing stress is important for maintaining a strong immune system and overall health.

Here are a few tips for managing your stress levels:

• Practice mindfulness; try deep breathing, meditation, or yoga
• Get regular exercise
• Get enough sleep every night
• Avoid too much caffeine
• Stay social; spend time with friends and family to relieve stress

Certain vitamins and minerals are crucial in boosting immune function, helping your body defend against illness. Research shows that a diet rich in vitamins A, C, D, and E, as well as selenium, zinc, and antioxidants, can enhance immune system strength and resilience.

The body absorbs nutrients better from whole foods than supplements, so getting vitamins and minerals through a balanced diet is essential. Here are a few ways to ensure you’re getting immune-boosting foods and nutrients in your diet:

• Eat colorful fruits and vegetables: For a variety of nutrients, choose vibrant options like oranges, spinach, bell peppers, kiwis, pomegranates, and carrots.
• Mix up your vegetables: Eat various vegetables, such as mushrooms, onions, and broccoli, to add diversity and boost your immune system.
• Incorporate healthy proteins: Foods like fish, eggs, beans, and nuts help support the production of immune cells.
• Add flavorful condiments and spices: Ingredients like ginger, garlic, and turmeric provide extra immune-boosting benefits.
• Limit processed foods: These often lack essential nutrients and can hinder your body’s ability to stay healthy.

Vitamin D plays a key role in activating immune cells. Research shows that low vitamin D levels have been linked to a higher risk of infections, including respiratory illnesses.

You can get vitamin D in three ways:

• Get out in the sun: Exposing your skin to sunlight is one of the primary ways to get vitamin D. However, make sure to moderate your sun exposure as too much could lead to skin cancer and aging.
• Eat vitamin D-rich foods: Salmon, eggs, and fortified dairy products are good sources.
• Consider supplements: If you live in a place with little sunlight, your healthcare provider may recommend taking a vitamin D supplement to maintain healthy levels.

Your gut contains trillions of bacteria that help regulate your immune system. Your immune system and gut are closely connected because 70% of your immune system is in your digestive tract. They work together to protect you from infections and create beneficial bacteria to keep your body strong.

When your gut microbiome is unhealthy, it can weaken your immune system and increase your risk of autoimmune diseases, where your immune system attacks your body.

Here are a few ways to support your gut health:

• Eat probiotic foods: Yogurt, kimchi, and sauerkraut contain good bacteria that can improve gut health.
• Increase fiber intake: Whole grains, fruits, and vegetables are rich in fiber, which feeds good bacteria in the gut and helps move things through the digestive tract. The recommendation for older children, adolescents, and adults is to eat 21-38 grams of fiber each day.
• Avoid unnecessary antibiotic use: Overusing antibiotics can kill beneficial bacteria and lead to antibiotic-resistant bacteria, making antibiotics less effective in the future.

Alcohol can weaken the immune system and make you more vulnerable to infections. Excessive drinking reduces the number of immune cells in your body, making it harder to fight off illness.

Consider these tips to reduce your alcohol consumption:

• Drink in moderation; limit alcohol to one drink per day for women and two for men
• Manage your triggers; if certain people or places tempt you to drink, consider doing alternative activities
• Choose healthier alternatives; opt for nonalcoholic drinks when possible.
• Get professional help to quit if you need it

In addition to the methods above, you can also:

• Take supplements if needed: Supplementing with vitamin C, zinc, and elderberry may help strengthen your immune system, but check with a healthcare provider first.
• Get vaccinated: Vaccines train your immune system to recognize and fight specific viruses.
• Practice good hygiene: Wash your hands regularly and avoid touching your face.

If you experience the following symptoms, you may have a weakened immune system:

• Frequent infections or illnesses
• Slow wound healing
• Constant fatigue
• Digestive problems
• Ongoing stress or anxiety

See a healthcare provider if you have these symptoms often, as they may indicate an underlying health condition.

A Quick Review

The immune system is the body’s defense against harmful germs and infections. Taking care of your immune system is essential for staying healthy and avoiding illness.

Prioritizing sleep, exercising regularly, eating a nutritious diet, and managing stress can strengthen your immune system. Limiting added sugar and alcohol and practicing good hygiene can also help.

Seek medical guidance if you frequently experience infections or illness, slow wound healing, and tiredness. These may be signs of a weakened immune system.