Sarah Thomas is pushing the limits of open-water swimming

Sarah Thomas has completed the English Channel, the Catalina Channel and the Manhattan Island Marathon Swim, as well as this record-setting 80-mile swim across Lake Powell and back. Ken Classen

The Horsetooth Open Water Swim in Colorado is an annual test for the hardiest of swimmers. Men and women, wearing swim caps and goggles, dive into the Horsetooth Reservoir, a dagger-shaped body of water just west of Fort Collins at more than 5,400 feet above sea level. They challenge themselves over a variety of distances, from just under a 2K up to a 10K.

In August of 2007, Sarah Thomas decided to try the 10K, though she'd never done such a long distance. She'd been good at longer races in the pool as a high school and college athlete, but she'd never tackled 6.2 miles. It seemed daunting as she stared out at the lake before the race.

"Really, I was thinking a 10K straight, without stopping, might be the farthest I could ever swim," says Thomas, from her home in Conifer, just southwest of Denver.

Yet Thomas was the second woman and fifth swimmer overall (out of 60) to finish, in 2 hours, 39 minutes, 8 seconds.

"I got out of the water, and I was fighting back tears because I loved it so much," she recalls. "I remember thinking, 'Why didn't I do this sooner? That was so much fun.'"

In the years since, Thomas, a 34-year-old recruiter for a health care company, has had loads of "fun" in marathon swims across the U.S. and Europe. Ultradistance swims have become her passion. She's completed the English Channel, the Catalina Channel and the Manhattan Island Marathon Swim (the triple crown of open-water swimming), plus Loch Ness in Scotland and Flathead Lake in Montana. She's also done back-and-forth crossings of Lake Tahoe and Lake Memphremagog (between Vermont and Canada).

Then, this past October, she completed her longest swim, a record-setting 80-mile, nonstop route across Lake Powell and back that took 56.5 hours. After, the Marathon Swimmers Federation gave her the Solo Swim of the Year award for the effort, calling it "the longest known nonstop, solo" swim in a "current-neutral" body of water.

The swim spanned two nights. On the first, it was so clear and dark that Thomas could see shooting stars through her goggles. But then the next night was so foggy that she and her support group had to feel their way through the lake, trying to avoid rocky outcroppings and steep canyon walls. At one low point, she swam in the wrong direction for about 30 minutes.

Thomas had been worried beforehand about going that long without sleep, but that didn't prove to be a problem. Small amounts of caffeine in the electrolyte supplement she drank during the swim -- along with nutrition drinks -- kept her awake. Still, how does a person swim continuously for more than 56 hours?

"I think that's where my gift is," Thomas says. "I can hold a pretty solid pace for a long time. I don't have the prettiest stroke when people watch me, there's a lot I could probably do if I wanted to swim faster, but I don't necessarily have issues with shoulder pain. ... So, as long as I've trained well, I can usually not fall apart."

She did have "a little mental breakdown" at 30 hours, because that was her previous longest nonstop swim. But she fell back on an old trick she uses during long swims. "Do my arms hurt?" she asks herself. "No. Am I sick? No. So what's your excuse for quitting? Nothing."

That Thomas fell in love with marathon swimming was no surprise. She began the sport early and was part of a year-round swim team by age 10. In high school she started out swimming short distances in the breaststroke, then gradually moved to the 200 and 500 freestyle, finally swimming the mile for the first time as a senior. At the University of Connecticut, she specialized in the longer distances up to a mile.

After graduating from UConn with a degree in political science and journalism, she moved on to the University of Denver to get her master's in legal administration. With so much going on -- school, part-time work, internships -- she stopped swimming. But once she graduated and started working in the human resources field, she eased into a more regular schedule and joined a master's swim team. That put her back in the pool a few times a week. When she heard people talking about the 10K swim at Horsetooth she was intrigued.

The open-water experience was more invigorating than anything she'd done before. "It was exhilarating to be in the open water and not have to do flip turns. And the people that do open water are a little bit more laid back. ... No lane ropes, being outside. It all fits."

That led to bigger things.

"When you're in the open-water community, you start meeting people who are like, 'Yeah, I did the English Channel' or 'I swam the Catalina Channel,' and you start thinking, 'That sounds like fun.'"

In 2010, she went for the 20-mile Catalina Channel swim in California -- and it was anything but fun. Though she finished it in a strong 9 hours, 6 minutes, she hated it. "It was the most painful swim I've ever done in my life," she says. "When I got done with it, I said I was never, ever swimming again. But clearly, that was a lie."

The long exposure to the salt water caused her tongue to swell. She chafed in places she didn't know she could chafe. She didn't get her nutrition right and hit the wall midchannel.

Despite all that, after she recovered, she vowed to give marathon swimming another shot. In 2011, she did the 28.5-mile Manhattan Island Marathon Swim. Supported by her boyfriend, Ryan Willis (now her husband), she had a great time. This time, she figured out her nutrition and pain management. "I was jumping up and down saying, 'Can I go around again? I want to go again,'" she recalls about the end of the race.

To keep up with the training for marathon swimming requires intensity, though. And not just in the water. To make her life work, Thomas schedules everything. "It drives my husband crazy, especially in the summer, when I'm really training," she says.

To make sure she's getting the miles she needs, she'll move things around on the schedule. If they want to do something on Saturday, that means doubling up on another day, or swimming seven days instead of six.

She works 8 a.m. to 5 p.m., so she gets up at 5 a.m. and does a 90-minute swim, then gets in another hour after work. On Saturdays -- when it's not winter -- she'll often do an early swim at Chatfield Reservoir, then a later session at Wellington Lake. She says that 98 percent of the time, that level of commitment is a satisfying part of her life.

But that 2 percent gets loud sometimes.

"I would say every summer there's probably a time when my husband is holding me, and I'm sobbing because I'm exhausted and burned out," she says. "And if it gets to that, I give myself a day or two off and kind of refocus. But mostly I enjoy it, especially the lake swimming."

Right now, Thomas hasn't figured out what her next big goal is. But there will be something else. "I was hoping to find my limit in 80 miles (at Lake Powell) and didn't find it. So my inner voice is saying, 'Sarah, go farther.'"