The most effective ways to avoid getting sick come down to a handful of consistent habits: washing your hands properly, sleeping enough, staying active, and keeping up with vaccines. None of these are surprising on their own, but the details matter more than most people realize. Small adjustments to how you do each one can make a measurable difference in how often you catch colds, the flu, and other common infections.
Wash Your Hands for a Full 20 Seconds
Handwashing is the single easiest thing you can do, and most people don’t do it long enough. Scrubbing for at least 20 seconds removes significantly more germs than shorter washes. That’s roughly the time it takes to hum “Happy Birthday” twice. Proper handwashing reduces respiratory illnesses like colds by 16 to 21% across the general population, according to the CDC.
The key moments are before eating, after using the bathroom, after blowing your nose, and after touching shared surfaces in public spaces like door handles, elevator buttons, or grocery carts. Soap and water outperforms hand sanitizer for most situations, but alcohol-based sanitizer (at least 60% alcohol) works when a sink isn’t available.
Prioritize Sleep Over Almost Everything Else
Your immune system does critical maintenance work while you sleep. When you’re sleep-deprived, your body ramps up inflammatory signals and becomes less effective at fighting off infections. Prolonged sleep loss triggers a cascade of immune disruption: elevated levels of inflammatory proteins, accumulation of certain white blood cells that signal the body is under stress, and dysfunction across multiple organ systems. In animal studies, extended sleep deprivation produces something resembling an out-of-control inflammatory response throughout the body.
For practical purposes, most adults need seven to nine hours per night. Consistently getting six or fewer hours leaves you measurably more vulnerable to whatever virus is circulating at your office or your kid’s school. If you’re the type to cut sleep to fit in an early workout, it’s worth reconsidering that tradeoff during cold and flu season. Sleep does more for your immune defenses than most other interventions combined.
Move Your Body Regularly, but Moderately
Regular moderate exercise appears to boost your body’s ability to detect and respond to infections early. Physical activity increases the circulation of antibodies and white blood cells, potentially helping them find and respond to pathogens faster. People who follow a moderately active lifestyle tend to get sick less often than those who are sedentary.
You don’t need intense training sessions. A moderate program looks like daily 20 to 30 minute walks, biking a few times a week, or hitting the gym every other day. The benefits seem to come from consistency rather than intensity. Extreme endurance exercise, like running a marathon, can temporarily suppress immune function, so more is not always better.
Keep Indoor Humidity in the Right Range
Dry winter air isn’t just uncomfortable. It helps viruses travel farther and survive longer. The commonly recommended range for indoor relative humidity is 40 to 60%, and there’s real science behind that number. At higher humidity levels, respiratory droplets from a sneeze or cough absorb more moisture and fall to the ground faster, which means less viral material stays floating in the air for you to breathe in. Viruses also tend to lose viability more quickly in humid conditions compared to dry air.
If your home drops below 30 to 35% humidity in winter (common in heated buildings), a simple humidifier in your bedroom and main living space can help. You can pick up a basic hygrometer for a few dollars to check your levels.
Clean High-Touch Surfaces Regularly
Viruses survive much longer on hard, non-porous surfaces than most people expect. On materials like plastic, stainless steel, and glass, infectious virus particles can persist for days. A 99% reduction in viable virus on these surfaces takes roughly 72 hours under normal indoor conditions, meaning that doorknob or light switch someone touched while sick on Monday could still carry live virus on Wednesday.
On porous surfaces like fabric, cardboard, and paper, viruses typically become undetectable within minutes to hours. Focus your cleaning efforts on the non-porous surfaces people touch most: phone screens, countertops, faucet handles, remote controls, and keyboards. Standard household disinfectant wipes or sprays are effective. During peak illness season, wiping down these surfaces once a day takes under five minutes and meaningfully reduces your exposure.
Get Your Flu Shot (and Stay Current on Vaccines)
The flu vaccine’s effectiveness varies by season, but it consistently reduces your risk of getting sick enough to need medical care. For the 2024-2025 flu season, preliminary CDC data shows the vaccine reduced outpatient flu visits by roughly 42 to 56% across all ages, depending on the monitoring network. For children and adolescents, effectiveness estimates ranged from 32 to 60%.
Those numbers aren’t perfect, but a coin-flip reduction in your odds of getting the flu is substantial, especially considering the vaccine takes about 15 minutes of your time. Even in years when the vaccine is a less precise match to circulating strains, vaccinated people who do get sick tend to have milder and shorter illnesses. The same principle applies to staying current on COVID boosters and other recommended vaccines.
Manage Chronic Stress
Stress doesn’t just make you feel run down. It physically weakens your immune defenses through a specific biological pathway. When you’re chronically stressed, your body produces elevated levels of stress hormones that directly interfere with T cells, the white blood cells responsible for identifying and destroying infected cells. These hormones alter the internal structure of T cells, disrupting their ability to activate properly and migrate to where they’re needed. The result is a measurably suppressed immune system and increased susceptibility to infections.
This isn’t about occasional deadline pressure or a bad day. It’s the sustained, unrelenting stress that lasts weeks or months: ongoing work conflicts, financial strain, caregiving burdens, or relationship problems. The interventions that help are the ones that genuinely lower your baseline stress level, whether that’s regular exercise, adequate sleep (which does double duty here), social connection, or professional support. Simply knowing that chronic stress makes you physically more vulnerable to illness can help you prioritize stress management as a health behavior, not just a lifestyle preference.
What About Supplements?
Two supplements have reasonable evidence behind them, though neither is a magic shield.
Zinc lozenges can shorten colds once you already have one, but the dose matters enormously. Clinical trials consistently show that daily zinc doses below 75 mg have no effect at all. Above that threshold, zinc acetate lozenges reduced cold duration by about 42%, while other zinc formulations reduced it by about 20%. Across all high-dose trials, the average reduction was 32%. The key is starting within the first 24 hours of symptoms and using lozenges that deliver enough elemental zinc per dose to hit that 75 mg daily total.
Vitamin D plays a role in immune function, and deficiency is common, especially in winter and among people who spend most of their time indoors. The recommended daily intake is 600 IU for adults up to age 70 and 800 IU for those over 70. If you suspect you’re deficient (limited sun exposure, darker skin, or living at a northern latitude), getting your levels checked and supplementing accordingly is reasonable. Mega-dosing beyond recommended levels hasn’t shown clear benefits for preventing illness and can cause harm.