This is the habit that does the most for the least effort. Dr. Westley Spiro, a board-certified emergency medicine physician at Mount Sinai, told ELLE that people who sleep under six hours “are several times more likely to get sick after exposure” than people who sleep seven or more.

There’s research behind that. In a study in the journal Sleep, 164 healthy adults wore sleep trackers for a week, then were given nasal drops containing a cold virus. Those who slept under six hours a night were about four times as likely to develop a cold as those who slept more than seven. It was a small study, so treat the exact number loosely, but the message is clear: short sleep makes you easier prey.

If the clocks changing has thrown off your rhythm, these tips for sleeping well when daylight saving time ends can help.

Spiro lists keeping vitamin D “in a healthy range” among the basics that help your immune system do its job, and notes that vitamin D levels tend to dip in fall. If you’re not sure where yours are, ask your doctor rather than guessing with high-dose supplements.

What about oranges and orange juice? They won’t prevent or cure a cold, according to ELLE, though the fluids can help you feel better when you’re sick. A normal, balanced diet is enough; there’s no need to stock up on garlic.

Cold viruses don’t only spread through the air. The CDC says droplets from coughs and sneezes can get into your body if you touch a contaminated surface, or shake hands with someone who’s sick, and then touch your eyes, nose or mouth.

That makes Spiro’s two basics a pair: wash your hands, and keep them away from your face. Wash before eating, after your commute and whenever you’ve been around someone sniffly.

Eight glasses of water a day won’t stop you from catching a cold. But fluids matter once you’re sick. Spiro says rest and hydration help your body clear the virus, and warm drinks, broth or chicken soup are comforting and hydrating.

Regular exercise is on Spiro’s list of habits that help your immune system. You don’t need a marathon; a brisk walk counts. Just ease off hard workouts if you’re already coming down with something.

Spiro also names managing stress and not smoking among the basics. Stress tends to shift with the season, along with sleep schedules. Anything that genuinely helps you unwind counts, whether that’s a walk, a call with a friend or a phone-free evening.

Cold weather itself doesn’t give you a cold. Colds are caused by viruses, and the CDC notes you can catch one any time of year. But Spiro says several things stack up in fall:

He adds that rhinoviruses, the biggest cause of colds, peak in spring and fall. Some of what feels like a cold at the change of season can also be allergies.

A warm bath or shower won’t kill a virus, but it’s a lovely way to switch off before bed. Then get into cozy pajamas and go to sleep a little earlier, which brings you right back to tip number one.

According to Spiro, the speed of onset is the biggest clue.

COVID-19 can look like any of these, Spiro says, so if you’re unsure, test. The CDC adds that flu, RSV and COVID-19 can cause cold-like symptoms but aren’t colds, and are more likely to cause severe illness. It recommends getting tested if you suspect COVID-19 or flu, especially if you’re at higher risk, because antiviral treatments work best when started soon after symptoms begin.

Spiro’s advice is to treat the first scratchy throat like the start of any illness: “Slow down early rather than pushing through.”

Colds are caused by viruses, so antibiotics won’t help. For more on that, read our things you should know about colds and flu.

The flu vaccine won’t stop colds, but the flu is a bigger deal than a cold and is worth preventing. The CDC says everyone 6 months and older should get a flu vaccine every season, with rare exceptions. For more ways to stay well, see our list of ways to avoid getting sick in cold and flu season.

Most colds run their course on their own. Spiro says to see a doctor if:

Also check in sooner if you’re pregnant, have a chronic health condition, or are caring for a baby or an older relative who’s sick.

Can you actually prevent a cold?

Not completely; more than 200 viruses cause colds, and you’ll be exposed to some of them. But hand-washing, keeping your hands away from your face, enough sleep, exercise, managing stress and not smoking all lower your odds.

Why do people get more colds in the fall?

More time indoors in close contact with others, cold dry air that dries out the lining of the nose, changes in sleep and stress, and dipping vitamin D levels, according to emergency physician Dr. Westley Spiro. Rhinoviruses, the most common cause of colds, also peak in spring and fall.

How can you tell a cold from the flu or allergies?

A cold creeps in with a scratchy throat, congestion and little or no fever. The flu hits fast with fever, chills and body aches. Allergies cause itchy eyes, sneezing and clear mucus, with no fever or aches. If you’re unsure, especially about COVID-19 or flu, get tested.

Does dairy make a cold worse?

No. Dr. Spiro says dairy doesn’t make your body produce more mucus, and studies haven’t shown it makes colds worse.

When should you see a doctor for a cold?

If you’re not improving after ten days, you develop a high fever or trouble breathing, or you get worse after starting to feel better.