Training for a marathon? It takes many months to properly train and prepare for a marathon. During the later part of this training period, most runners choose to dramatically cut back on their mileage in the weeks before the race.

After the hard workouts are done, it’s tempting to just sit back on the couch and load up on carbohydrates with a big plate of pasta. But don’t let your guard down too much, since many athletes get sick prior to a big event.

Here’s a look at why runners might fall ill before a marathon and how to prevent it from happening to you.

Tapering is the last step in a marathon training regimen. This is the practice of decreasing the distance and length of your workouts in order to give your body time to rest and recover before the race.

Depending on your running plan, your taper will likely start two or three weeks before the race. Your mileage will decrease significantly during this time. Your last and probably longest distance run (likely 18 to 20 miles) should be completed before you start to taper.

It’s important to keep up with shorter runs and workouts during the last weeks of training to maintain the level of fitness that you worked so hard to reach. The hard workouts are over, but you still want to stay in shape.

Your body should feel relaxed and ready on race day, not sluggish and heavy. That being said, many runners get nervous and overtrain instead of backing off.

In general, moderate runners, fitness enthusiasts, and master’s athletes are a healthy bunch. When asked, 60 to 90 percent of these individuals reported having fewer colds than their peers who didn’t work out.

But elite and endurance athletes who train more intensely might be at a greater risk for upper respiratory tract infections (URTI). A study published in The Journal of Sports Medicine and Physical Fitness found that many Los Angeles marathon participants self-reported infectious episodes both during periods of intense training and after the race.

Why? Experts believe immune function might be altered and may even be suppressed for a period of time after prolonged or intensive exercise.

According to Dr. David Neiman’s open window theory, in the three to 72 hours after an intensive training session or race, your immunity may be suppressed. That means it might be easier for viruses and bacteria to take hold, increasing your risk for infection.

If tapering begins immediately after your most intense period of training, the open window theory would explain why runners get sick during this time. But more research is needed to understand exactly what’s happening to the immune system in endurance athletes.

Regardless, it’s especially important to rest and not overexert yourself both before and after a marathon.

Think about your marathon taper as a short breather before the main event. You’ll cut back on workouts, leaving more time for relaxation and rest.

Here are some ways to stay healthy while tapering before a race.

1. Don’t go carb crazy.

Adding an extra serving of carbs to each meal the week before the race is a good idea. Carbohydrate loading can increase the amount of glycogen in your muscles, giving you more energy for an endurance event. But don’t go overboard on bread and pasta. Runners who eat too many carbs may experience weight gain, mostly from water weight. This can slow you down on race day.

To avoid this, stick to your normal diet as much as possible. Adding a banana or small piece of bread to each meal will give you the extra energy you need. The night before the race, eat a well-balanced meal: a good amount of quality carbs with a balance of healthy proteins and fats.

2. Don’t try anything new.

If you are about to run a marathon, this isn’t the time to try any new activities like backcountry skiing or bungee jumping. You want to stay injury-free and let your body rest before the race. If you’re running a destination race, stick to light walking and schedule sightseeing for after the race.

Also avoid the urge to try new foods like lentils or turnip greens for the first time. Untested foods may lead to gastrointestinal issues during your race. Sticking to your regular diet as much as possible will keep your digestive track happy.

3. Hydrate.

You know you need to stay adequately hydrated before your race. It helps improve performance, and dehydration can hurt your performance.

Steer clear of alcohol, coffee, and soda when possible.

4. Avoid overtraining.

It’s natural to be nervous before the marathon. Most runners question if they trained hard enough to make it through, especially if it’s their first race. But it’s important to trust the training and miles you put in. Overtraining prior to the race will just leave you fatigued and irritable at the start line.

5. Sleep.

It’s crucial to get plenty of rest in the week before a marathon. Resting your body will help you recover from training. Even if your nerves keep you from getting much sleep the night before the race, you’ll still feel great at the start line.

After months of planning, training, and anticipation, it can be tough to decide whether or not you should skip the race because you’re sick. But running while you’re seriously ill or injured can be dangerous.

Consider the neck rule. If your symptoms are above the neck, like a runny nose or sore throat, you probably won’t endanger yourself by racing.

But if it’s something more serious like a chest cold, bronchitis, or a full body ache, you need to take time off and see your doctor. If you have a fever above 99˚F, stay home. There will always be another race to sign up for.