The most effective way to avoid catching a cold is layering several simple habits: washing your hands properly, sleeping enough, staying active, and managing your indoor environment. No single trick eliminates your risk, but combining these strategies can cut the number of colds you get each year significantly. Here’s what actually works.
Wash Your Hands for 20 Seconds
Handwashing reduces respiratory illnesses like colds by 16 to 21% in the general population. That’s a meaningful drop from something that costs nothing and takes half a minute. The key detail most people skip is duration: washing for 15 to 30 seconds removes substantially more germs than a quick rinse. The widely accepted target is 20 seconds with soap and water, which is roughly the time it takes to hum “Happy Birthday” twice.
Timing matters as much as technique. The highest-value moments to wash are after you’ve been in a public space, before eating, after blowing your nose, and after touching shared surfaces like doorknobs, elevator buttons, or shopping carts. When soap and water aren’t available, an alcohol-based hand sanitizer works as a backup, though it’s less effective on visibly dirty hands.
Keep Your Hands Away From Your Face
Cold viruses enter your body through your eyes, nose, and mouth. The main vehicle is your own fingers. Most people touch their face dozens of times per hour without realizing it, transferring viruses picked up from contaminated surfaces directly to mucous membranes. Rhinovirus, the most common cause of colds, can survive on hard surfaces like stainless steel, countertops, and plastic for up to three hours. That’s long enough for a doorknob touched by a sick coworker in the morning to still be infectious at lunch.
Building awareness of face-touching is one of the simplest and most underrated prevention strategies. If you tend to rest your chin on your hand or rub your eyes, try to notice the habit and redirect it. Keeping tissues nearby for nose itches and using a knuckle instead of a fingertip to scratch can help break the chain of transmission.
Sleep 7 to 8 Hours a Night
Sleep is one of the strongest predictors of whether you’ll catch a cold after being exposed to one. People who sleep five hours or fewer per night are 44% more likely to report getting a cold compared to those who sleep seven to eight hours. Interestingly, oversleeping doesn’t help either: sleeping nine or more hours is associated with a 20% higher likelihood of illness, possibly because excessive sleep can signal or contribute to other health issues that weaken immune function.
The sweet spot is consistently getting seven to eight hours. This isn’t just about one good night before a flight or a holiday gathering. Your immune system’s ability to fight off viruses depends on sustained, regular sleep patterns. If you’re chronically short on sleep during cold season, that alone could be one of the biggest risk factors you’re not addressing.
Exercise Regularly at a Moderate Pace
People who follow a moderately active lifestyle get sick less often than those who are sedentary. You don’t need intense gym sessions to see a benefit. A moderate routine looks like daily 20 to 30 minute walks, biking a few times a week, or going to the gym every other day. The goal is consistency over intensity.
There’s a nuance here worth knowing. Moderate exercise supports immune function, but prolonged, intense exercise (like marathon training) can temporarily suppress it. If you’re already active at a high level, the cold-prevention benefit comes from maintaining your routine without overtraining, especially during peak cold season in late fall and winter.
Manage Indoor Humidity
Dry indoor air, common during winter when heating systems run constantly, helps respiratory viruses spread more easily. Research from the U.S. National Science Foundation found that keeping indoor relative humidity between 40% and 60% is associated with reduced transmission of respiratory viruses. Below 40%, the tiny droplets carrying viruses shrink and float in the air longer, and your nasal passages dry out, making them less effective as a barrier. Above 60%, you risk mold growth, which creates its own set of respiratory problems.
A simple hygrometer (available for under $15) lets you monitor humidity levels at home or in your office. If your air is consistently dry, a humidifier can bring levels into that 40 to 60% range. Clean it regularly to prevent bacteria and mold from building up inside the unit.
Get Enough Vitamin D
Vitamin D plays a direct role in immune defense, and people with low levels get sick more often. In one study, 70% of people with severely deficient vitamin D levels reported respiratory illness, averaging three infections per year, compared to about 50% of those with adequate levels. During winter months, when sun exposure drops, many people fall into insufficient or deficient territory without realizing it.
You can maintain healthy vitamin D levels through a combination of moderate sun exposure (10 to 15 minutes a few times per week for lighter skin, longer for darker skin), foods like fatty fish and fortified milk, or a daily supplement. If you live in a northern climate or spend most of your time indoors, a supplement during the colder months is a practical option. A blood test can confirm where your levels stand if you’re unsure.
Consider Probiotics
There’s growing evidence that certain probiotic bacteria can reduce how often you catch upper respiratory infections. Multiple clinical trials have found benefits from various Lactobacillus strains, with studies showing reduced cold incidence and duration in groups ranging from children to older adults to people under high psychological stress. The effects likely come from probiotics strengthening the immune response in your gut, which is closely linked to overall immune function.
The research is promising but not yet definitive enough to recommend specific strains or doses with confidence. If you want to try probiotics, look for products containing well-studied strains like L. rhamnosus GG or L. casei Shirota, which have the most clinical data behind them. Fermented foods like yogurt, kefir, and kimchi are another way to support gut bacteria without committing to a supplement.
What About Zinc?
Zinc lozenges are widely marketed for colds, but the evidence is more about treatment than prevention. When dissolved slowly in the mouth (not swallowed whole), zinc lozenges providing over 75 mg of elemental zinc per day have shortened cold duration by about 33% in clinical trials. The benefit appears to come from zinc acting locally in the throat rather than being absorbed systemically. For actually preventing colds before they start, though, the current evidence isn’t strong enough to make a firm recommendation. Zinc lozenges are better thought of as something to reach for at the first sign of symptoms rather than a daily preventive habit.
Avoid Sick People When You Can
This sounds obvious, but it’s worth being deliberate about. Colds spread through respiratory droplets when someone nearby coughs or sneezes, and through direct contact like handshakes or shared objects. During periods when respiratory viruses are circulating heavily in your community, the CDC recommends considering additional measures like physical distancing and wearing a mask in crowded indoor spaces, especially if you or the people around you are at higher risk for complications.
Improving ventilation also helps. Opening windows, using air purifiers with HEPA filters, or simply spending more social time outdoors rather than in stuffy rooms reduces the concentration of airborne virus particles. When someone in your household is sick, simple steps like having them use a separate bathroom, wiping down shared surfaces, and sleeping in a different room can meaningfully limit spread within the home.