The Honolulu Marathon is Dec. 10, and those of you who will be participating should be in your final phase of training.

This phase includes the longest training runs, which over the course of a few months, has been built up to 3 to 4 hours.

The final long run — from 15 to 20 miles, or 2 1/2 to 3 1/2 hours of running — should be done in the next few days. Afterwards runners should start to taper off their distances.

By slowly increasing the length of the long run over weeks of training, you are gradually increasing stamina and improving your ability to tolerate longer periods of stress.

In other words, you are allowing your body to adapt properly and gradually.

Local banker Robert Gardiner, 38, has run three marathons.

"Without (an) adequate slow build-up of long training runs, I would not be able to achieve my marathon goal," he said. "In addition, I fear injury may result from just going out and doing a marathon without these runs."

Direct benefits of the long run include the body becoming more efficient in carrying oxygen to the muscles, the muscles receiving increased blood and strengthening the heart.

It also teaches your body how to burn fat more efficiently, which is important in marathons.

There are two types of fuel that you run on: fat and glycogen (sugar).

There is an abundance of fat in your body, but glycogen is not as plentiful. Increasing your ability to burn fat will enhance performance because your body will use more fat as fuel.

Glycogen is critical fuel for your body that will burn quickly. Therefore, it is important to conserve as much of this glycogen as possible, because when you run out of glycogen that is when you "hit the wall."

Like a car, the more fuel you have, the farther it will go at a constant speed.

The long training run should be done at a conversational pace or at a low heart rate. Running it slow and relaxed means that you are running with more oxygen. This is what is going to increase the percentage of fat that you can burn and make you last longer.

The thing to remember during your long training run is that the time spent running is important, not the intensity.

Angela Sy, 39, a research evaluator for the John A. Burns School of Medicine, finds long runs enjoyable.

"Long runs carry less pressure to have to run hard and it is easy to carry on a conversation with a fellow runner," she said. "I almost always run them with a partner or group. I see it as being engaged in physical activity and in the company of others."

Long runs will teach your body to adapt and eventually run for longer distances at a pace you were able to run at a shorter distance. This is how long runs increase stamina and endurance. Over the course of your training, your body will allow you to run longer periods of time at a lower heart rate.

In addition to helping your body adapt to the marathon distance, long runs will help you build mental discipline.

It will not make the marathon distance seem as daunting if you have already been running several hours in training.

"Running these runs will let you know how your body feels and teach you how to pace yourself properly," said Sy, who will be running in her eighth marathon. "Mental adaptations come when I do long runs. It gives me the ability to experience things that might come up."

The marathon is an endurance event, so the goal is to last longer at a certain pace. This is why long runs are a key component when training for a marathon. It will help determine whether you are going to have a good marathon and may help you avoid hitting that dreaded "wall."

Mike Kasamoto, 57, a veteran of five marathons, summed it up.

"Long runs help adapt your legs and body and mind to the rigors of the marathon. I would definitely hit the wall sooner without those long runs," he said.

Jonathan Lyau is a 12-time kama'aina winner of the Honolulu Marathon. He will be writing a series of articles leading up to The Honolulu Marathon.