When you’re already fighting a cold, flu, or other respiratory illness, pneumonia is one of the most serious complications that can develop. The good news: most cases of secondary pneumonia are preventable with deliberate steps to keep your lungs clear, your airways moist, and harmful bacteria out of your respiratory tract. Here’s what actually works.
Why Being Sick Makes You Vulnerable
Viral infections don’t just make you feel terrible. They physically damage the lining of your airways. When a virus like influenza attacks your respiratory cells, it strips away the protective barriers that normally keep bacteria out. The tight junctions between cells break down, and bacteria that would normally be trapped and expelled can now slip deeper into your lungs.
Your body also responds to viral infection by displaying certain proteins on cell surfaces that bacteria, particularly pneumococcus, latch onto more easily. Meanwhile, the fluid balance in your airways shifts. The damaged lining leaks fluid, blood cells, and immune cells into the tiny air sacs where gas exchange happens, making it harder to breathe and creating a warm, moist environment where bacteria thrive. This is why pneumonia so often follows a bad bout of flu or another respiratory virus rather than appearing out of nowhere.
Keep Your Lungs Expanded
When you’re sick, you tend to breathe shallowly, lie still, and avoid deep breaths that might trigger coughing. That’s exactly what sets the stage for pneumonia. Shallow breathing allows the small air sacs at the base of your lungs to partially collapse, a condition called atelectasis. Once those areas close off, mucus pools there, and bacteria move in.
Deep breathing exercises are one of the simplest and most effective countermeasures. If you have an incentive spirometer (the plastic breathing device often given after surgery), use it for 10 to 15 slow breaths every one to two hours. Breathe in slowly through the mouthpiece, hold for three to five seconds, then exhale. If you don’t have one, you can do the same thing without the device: sit upright, inhale slowly and deeply through your nose until your lungs feel fully expanded, hold for a few seconds, and exhale slowly. Repeat 10 times, and do this several times throughout the day.
The key word here is “sit upright.” Lying flat compresses your lungs. Propping yourself up at a 30 to 45 degree angle, even while resting, gives your lungs more room to expand and helps mucus drain downward rather than pooling in the lower lobes.
Move, Even a Little
Prolonged bed rest weakens your respiratory muscles, reduces circulation, and increases the risk of lung collapse. You don’t need to exercise while sick, but you do need to get up and move periodically. Even short walks around your home, standing up to stretch, or sitting in a chair instead of lying in bed makes a meaningful difference. Early movement helps maintain muscle strength, improves oxygenation, and supports the mechanical process of clearing mucus from your airways.
Aim to get up and walk for a few minutes every couple of hours during waking hours if you can manage it. If you’re too weak for that, simply sitting upright in a chair and doing your deep breathing exercises is far better than lying flat all day.
Stay Hydrated to Keep Mucus Thin
Your airways are lined with a thin layer of mucus that traps particles and pathogens, and tiny hair-like structures called cilia sweep that mucus upward and out. This system works well when the mucus is properly hydrated. When you’re sick, especially with fever, you lose fluid faster through sweat and rapid breathing. Dehydrated mucus becomes thick and sticky, harder for cilia to move, and more likely to clog small airways.
Your body regulates airway hydration through ion transport across the cells lining your airways. Drinking fluids doesn’t directly thin mucus the way water dissolves sugar, but adequate systemic hydration supports the cellular machinery that keeps your airway surfaces moist. Water, broth, herbal tea, and electrolyte drinks all count. A good rule of thumb is to drink enough that your urine stays pale yellow. If you’re running a fever, increase your intake beyond what feels natural.
Don’t Suppress Your Cough Entirely
A productive cough, one that brings up mucus, is your body’s primary mechanism for clearing debris and bacteria from your lungs. Reaching for a cough suppressant every time you cough can work against you by allowing mucus to accumulate deeper in your airways. If your cough is productive, let it do its job during the day. Cough suppressants are more appropriate for dry, non-productive coughs that interrupt sleep and don’t serve a clearance function.
When you do cough, make it count. The “huff cough” technique is more effective than a weak, half-hearted cough: take a medium breath, then force air out in a sharp “huff,” like you’re fogging a mirror. This generates enough airflow to move mucus up without the violent force that can collapse small airways.
Brush Your Teeth
This one surprises people, but oral hygiene has a direct connection to pneumonia risk. Your mouth harbors billions of bacteria, and when you’re sick, lying down, or breathing through your mouth, those bacteria are more easily inhaled into your lower airways. A study of hospitalized patients found that those who brushed their teeth twice or more daily were 33% less likely to develop pneumonia than those who didn’t maintain an oral care routine. Hospital-acquired pneumonia is largely caused by inhaling germs from the mouth and throat, and the same principle applies at home.
Brush at least twice a day, and consider using an antiseptic mouthwash. This is especially important if you’re spending a lot of time lying down or if your illness involves vomiting, which coats your mouth with additional bacteria.
Optimize Your Indoor Air
Dry air irritates your airways, impairs the mucus lining, and makes it harder for your cilia to function. The Mayo Clinic recommends keeping indoor humidity between 30% and 50%. A simple room humidifier can help, particularly during winter months when heating systems dry out indoor air. If you don’t have a humidifier, placing a bowl of water near a heat source or spending time in a steamy bathroom after a hot shower provides temporary relief.
Keep your humidifier clean if you use one. A dirty humidifier sprays mold and bacteria into the air, which is the opposite of what you need. Change the water daily and clean the unit according to the manufacturer’s instructions.
Make Sure Your Vaccines Are Current
Vaccines won’t help you right now if you’re already sick, but they’re the single most effective long-term strategy against pneumonia. The CDC recommends pneumococcal vaccination for all adults 50 and older, and for adults 19 through 49 who have certain risk conditions like diabetes, heart disease, lung disease, or a weakened immune system. Current options include PCV15, PCV20, or PCV21. If you receive PCV15, a follow-up dose of a different pneumococcal vaccine is recommended.
An annual flu shot also reduces pneumonia risk indirectly by preventing the viral infections that most commonly lead to secondary bacterial pneumonia in the first place.
Warning Signs That Pneumonia May Be Developing
Even with good prevention, pneumonia can still develop. The classic pattern is a “double hit”: you start feeling better from your original illness, then suddenly worsen again with new or more severe symptoms. Watch for these specific changes:
- Fever spiking to 102°F (38.9°C) or higher, especially after your original fever had started to improve
- Cough producing yellow, green, or bloody mucus, particularly if it was previously dry
- Shortness of breath or rapid breathing that feels out of proportion to your activity level
- Chest pain that worsens with coughing or deep breaths
- Rapid heart rate, confusion, or bluish discoloration of your lips or fingernails
Any of these, particularly in combination, warrants prompt medical evaluation. Pneumonia caught early responds much better to treatment than pneumonia that has had days to progress. Adults over 65, people with chronic health conditions, and anyone with a weakened immune system are at highest risk and should have a lower threshold for seeking care.