If you are one of the 22,000 runners preparing to run this weekend’s Houston Marathon or Half Marathon, you might be wondering how you should spend the final hours leading up to the big day. Odds are you will make at least one bad decision, especially if this is your first big race.

But don’t worry; to save you some agony, I’ve put together a list of the top 10 things you should NOT do between now and the Sunday morning start.

10. You decide to hit the drive-thru on your way to the marathon. Bacon? Waffles? Frappuccino?!

Sure ... you're about to burn 2,600-plus calories during your trek through Houston, but you better save your indulgences for after the race. The last thing you want to do is try some new breakfast the day of the race and end up feeling sluggish with stomach problems. Stick to what you know works for you and that probably means a high-carb, low-sugar, and low-fiber meal a few hours before.

9. Go to El Tiempo Saturday night and down two margaritas because you are already in celebration mode. Why not?

The main reason is dehydration. I’m not saying you can’t have a glass of wine with your Saturday dinner, but just don’t overdo it. Start hydrating now so that you don’t guzzle water the morning of the race and spend the day waiting in lines at the porta potties. The night before, just eat and drink what you normally do and include a little extra carbs or pasta.

8. Decide to “go for it” even though your last long run was a 10-miler this summer. If you haven’t been training properly, you have a greater chance of hurting yourself and getting an injury.

Sure, you can brag to your friends about how you strained your IT band at mile 18, but you will be limping for weeks. Adrenaline can only get you so far, and rarely last 26.2 miles. Be smart and that might mean opting for another race this spring.

7. You are tired of looking bad in your race photos, so you slather on self-tanner before you head out the door. Yes, we all want to look cute and get some Facebook worthy photos from brightroom, but putting on makeup or anything that will streak is just wrong.

It will sweat off by mile three and you’ll end up looking like a tiger. Save it for your celebration Sunday night!

6. You assume your iPod is packed with rockin’ tunes, but really your playlist hasn’t been updated in six months. Beware, because you could have leftover “Poetry Off the Shelf” as your last upload. The last thing you want to find at the start line is that your only motivational tool is Edgar Allan Poe. Finish your playlist today, make sure it’s uploaded and that iPod is charged.

5. You didn’t want to get those pretty new shoes and laces dirty at Memorial Park, so you are going to debut them on race day! Yay! Not quite. Be prepared for blisters, possible shin splints and even knee problems.

Your shoes can make or break your race, so be sure to run in a pair you have trained in, ones that you know work for you.

4. You sample some new cool “Xtreme Gel” with chocolate and 5x caffeine at the Expo and decide to use it as fuel during the race. The Marathon Expo is a great place to get new gear, gadgets and food and there are always free samples of the latest and greatest race gels.

It may taste good at the Expo, but if you haven’t tried it out during one of your training runs …don’t do it Sunday! Stick to what you know works for your stomach and odds are it won’t have the word “Xtreme” in it.

3. You get the sudden urge to hit the gym on Saturday because you think your quads could be a little stronger. Please stay away from the leg press, or any heavy weights for that matter.

By now there is nothing left to do to but relax and do some easy stretches. You aren’t going to make yourself any stronger or faster the last week before a race. So, you might as well chill and avoid pulling out your back, hamstring or quads.

2. You wake up not so bright-eyed Sunday morning and accidentally put on your significant other’s Nike capri pants and head out the door. Sunday morning is not the time to try a new outfit or make last minute decisions.

So, lay out your outfit the night before and include everything from your hat, socks, hand warmers and gels. Also, we all know how unpredictable H-town weather is, so include disposable outer layers like a jacket and poncho. Most likely you will have to toss it in the trash along the way, so don’t wear anything good.

1. Freak Out. Yes, we all want to get PRs and claim this was our best race ever. But, you’ll do best if you relax, put your feet up and prepare to just have fun the day of the race.

Look for the Elvis impersonators, cloggers and thousands of funny signs to get you through (My favorite from last year was “That’s not sweat … it’s your fat cells crying!”). You can do it! I’ll see you at the finish line.

Cari Shoemate is an ACE-certified personal trainer, group fitness instructor and certified yoga instructor. You can get more of her fitness tips at Cari-fit.com.