Cold weather and a lack of sunlight can suppress the immune system — learn how to fight back.

1) Attack of the Germs

Cold and flu season is officially upon us, and when you pair all those germs with a poor diet, you’re creating the perfect situation to get sick. Click on through to see what you’re doing daily that’s wrecking your immune system and how to remedy the situation—stat.

2) Not Getting Enough Sleep

Your body needs rest to heal and generate properly. When you cut your snoozing time short, you’re lowering your immune system and the number of protective “killer” cells that fight infections. If you find that you’re waking up tired it may be a sign that you’re not sleeping enough or getting quality shut eye.

The Fix: Aim to get 7-9 hours of quality sleep every night. If you have several events to attend, try to grab a catnap if possible or prioritize your events.

3) Overdoing It On Party Foods and Drinks

A poor diet is a common occurrence during the holiday season. There’s a good chance you’ll be faced with a number of office parties, friend get-togethers, and family gatherings. But if you consume too much alcohol, fats, and sugars at these events, your immune system can become compromised by reducing the effectiveness of white blood cells. Foods high in sugar can lower the ability of white blood cells to kill germs, starting about 30 minutes post-ingestion and lasting as long as five hours. As for excess alcohol will make your liver work harder to detoxify your blood, ultimately robbing your immune system of precious nutrients to fight off bacteria. Consuming three or more alcoholic drinks are enough to do just that. And lastly, fat lowers your antibody production and can cause a slow reaction to an infected area.

The Fix: Before arriving at the party, eat a balanced meal or snack. This will keep you from attacking the buffet and digging in to foods you might not normally eat. Look for vegetable platters with hummus or salsa, salads without creamy dressings and lean proteins like chicken skewers and shrimp cocktails are great to add to your plate, too. For dessert, try fruit and if you need a cocktail go for a wine spritzer with ice and seltzer, or sip vodka with seltzer and lime. It’s fine to put a small portion of a treat or two on your place, just make sure it’s surrounded by healthy foods.

(Learn the other 6 “Worst Things for Your Immune System” on Muscle & Fitness Magazine)

If you’re not feeling sore right after your workout, just wait, because you will.

There’s nothing better than the feeling you get after a hard workout, but when you don’t feel sore the day after, you might feel like you didn’t get the hardcore pump you thought you did. Just wait! As the day goes on, muscle soreness will creep up and you’ll feel as if you’ve moved mountains. The reason: delayed onset muscle soreness or what is better known as DOMS.

What is DOMS?

There was the belief that delayed onset muscle soreness results from a buildup of lactic acid or metabolic waste. That theory has since been dismissed. Delayed muscle soreness happens when there are small tears in connective tissue followed by inflammation to the muscle fibers. These tears happen during the eccentric (lengthening) part of the movement. For example, running down hill or during the lengthening part of a bicep curl.

Everyone can fall victim to DOMS, from the newbie who’s just starting out to the seasoned bodybuilder. The only real difference is that a bodybuilder may not experience the same severity as a first timer. The reason: seasoned athlete’s muscles are more accustomed to the workload put on it.

Delayed soreness is usually present 24-48 hours after the muscles have been exercised. This is because the muscles are stressed more than what they’re used too. This can also be a sign that the muscles are getting stronger or are growing (hypertrophy). You should notice the pain disappearing in about two to three days after the initial workout. Now, if you find that the pain is not disappearing or letting up, this could be a sign that something more serious may be wrong. Always listen to your body and never push a muscle if the movement is painful.

(Read more on Muscle & Fitness Magazine)