If you are running 50 miles per week, and knocking out 19 and 20 milers before the race, then it sounds like you are certainly prepared! There are many factors that can impact a marathon completion, and training (the most important factor) is something that you are doing well.

On top of the training, I would be sure to load carbohydrates for a couple of days before the race, and then plan on using gels during the race. How many gels you will need is something you can figure out when you do your 20 milers. To figure out how many gels I need, I add up the number I use in a 20 miler, and then add three more for miles 20, 22, and 24.

Anxiety is normal prior to attempting something this big. Just imagine yourself crossing the finish line!

One final thought - you have put in hundreds of miles of training, and 20 mile runs, all without crowd support, aid stations, or the promise of a medal at the end. You have already done the hardest part, and I think you will find race day to be a wonderful experience.

As everyone above has stated, you've done the hardest part...the training. Now trust it. It is structured a certain way to derive the benefits during the actual 26 miles. You may not understand the why's of doing things a certain way in training (yet), but it works to get you through.

Remember, about the only thing you cannot control is the weather or the make up of the field of runners that you'll be amongst. But you have a great deal of control over many other things, like what you wear, what you take as supplemental energy, how fast you run (particularly at the beginning of the race).

Going out too fast is probably the one thing to really be on the look out for. A person I know, training to run her first marathon at the same time I was training for mine, did all the training and it was clear that she was much faster than I was (and that I may ever be given the difference in age). Realistically, she thought that her time would be around 3:45-4:00 (or about an 8:35-9:09 pace). She went out in a race a couple of weeks before I ran mine and bonked at mile-16. The last ten miles were "brutal."

She finished in 5:35, nearly two-hours behind her best optimistic pace. She was disheartened by that. I finished in 5:10 and I ended up with a minor tear of my left Achilles tendon from rolling my foot downhill at mile-14 by stepping on a sweetgum seed pod. I was on pace up to that point for a 5:00 finish, so even though I couldn't run effectively uphill, I still didn't lose too much time. So what happened to her and why did she end up finishing a flatter course than mine in a time much slower than mine? She was caught up in the speed of the crowd and didn't monitor her pace because she felt fine.

That is right up to mile-16 and then the wheels fell off. But she was also running at a pace of around 7:30/mile, nowhere near what her training would support. So, two hours and 16-miles into her marathon, she was gassed and she spent the next 3:35 walking to the finish. She was one of those slow-moving zombies.

So, the best advice for your anxiety...monitor you pace at the start of the race, particularly in the first three miles. Don't be afraid to intentionally go slower. What extra energy you burn off then cannot be "recovered" later in the race. I've had that happened to me....once. Lesson learned.

Otherwise, if you trust your training, you'll do great!