But she won't be alone.
"There's always someone who gets you the next mile or something. So yeah, absolutely. The days you don't have them around, you just don't do as well," Bell added.
Her female running group will be right beside her. Some of them are veterans.
"I used to live here," Diane Gunderjahn said. "We used to train as a big group. So it's a big social group."
Some are rookies. "I had a very lazy summer and I kind of needed to do something to get a bit of energy and into shape," Yvette Wilson said.
Elite runners like Elva Dryer, the defending champion in the Houston half-marathon, says it is not surprising to see a surge in female entrants.
"Not only is it getting more and more competitive at the elite level, but it's a sport that the average person can get in and set goals for themselves," Dryer said.
While Diane Bell and her running group may finish an hour or two behind Dryer, just getting to the finish line is enough for them.
On-air coverage of the marathon will also be streamed live on abc13.com starting at 7am Sunday. We'll also have live streaming video of both the marathon and half marathon finish lines.
"The Finish Line" postrace show will air Sunday night at 10:35 on ABC13.
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