MONTREAL - Running 25 kilometers is hard enough, but try swimming the distance through a churning, wind-swept sea amid a thrashing mob while the scorching sun bakes your back.
And then try loving every second of it.
That's the life of open-water swimmers, the curiously content marathoners at this week's world swimming championships.
"It's definitely more fun going out into the ocean or a lake as opposed to doing laps and flip turns in a pool all day," said 17-year-old American Chip Peterson, a silver medalist in Sunday's 5-kilometer race, the first of three open-water events in the weeklong competition.
Peterson finished second to Germany's Thomas Lurz, who won the 5K in 51 minutes, 17 seconds. On the women's side, 16-year-old Russian Larisa Ilchenko took the women's gold in 55 minutes, 40 seconds.
The 10-kilometer race is Wednesday and the men's and women's 25K events are this weekend.
Though the roots of the sport can be traced to the first crossings of the English Channel in the late 1800s, it's relatively new in its current form. FINA, swimming's world governing body, started recognizing open-water racing in 1986 and it still isn't in the Olympics.
American coach Rick Walker thinks it will get there soon.
"There's no reason it shouldn't," he said. "I see this as the purest form of swimming, in an uncontrolled environment, where there are no walls or barriers."
In Montreal, the competitors are finding conditions more placid than they encounter in other parts of the world, where races are held in jungle rivers, mountain lakes or expanses of ocean.
Here, competitors are racing in a glassy enclosed basin that was used as the rowing venue in the 1976 Olympics. The freshwater is pumped in from the nearby St. Lawrence River.
The calm surface belies how violent things can get under the water, mostly in the shorter races. The two dozen or more swimmers shove, grab, kick and tug other competitors' bathing suits for an edge.
On Sunday, four-time world champion Edith Van Dijk took a shot in the mouth while winning the bronze in the 5K.
"There were so many bodies and you get kicks from everybody as some people swam across you," said the 31-year-old Van Dijk.
South African Kenneth Smith finished 29th in the 5K after taking a bruising smack to his left shoulder.
"You mix it up. It can be pretty rough and tumble," said Smith, who will compete in the 10K. "One of the Italian guys got hit in the eye by an Egyptian guy and got all cut up."
The cutthroat tactics don't end with pro wrestling moves.
Swimmers smear Vaseline over their bodies before each race to limit abrasions from their suits. They avoid putting it on their hands to keep it from smearing their goggles. But a few sneaks coat their feet with the jelly, knowing that opponents' hands might rub against their feet during races.
Referees oversee the races from small pontoons and can disqualify swimmers for interference. They can also call drafting if they see swimmers saving energy by traveling in the wake of others, similar to race-car drivers using the clean air behind other drivers.
FINA also has set conditions for open-water venues - minor currents, a minimum water temperature of 57 degrees and a minimum depth of one meter.
But the parameters still provide wide variation.
One recent race snaked down the Parana River in Argentina. Another crossed Lake Geneva in the Swiss Alps. A Hong Kong event plunged swimmers into the Indian Ocean.
"There is just no other race like any other one," said 25-year-old German Britta Kamrau, the defending world champion in the 10K and 25K. "You always have to examine yourself, but you also have to consider the weather, wind, waves, water temperature and, of course, the competition."
And the special moments keep them all coming back for more.
At an event in Hawaii, Kamrau watched sea turtles glide beneath her. When American Erica Rose won the first 5K championship seven years ago in Perth, a school of dolphins followed her to the finish.
In Argentina in March, Alaskan Sean Seaver of Ketchikan saw thousands of fans cheering on the banks of the Parana as he finished 11th in an 88-kilometer race that had a $10,000 purse. Seaver was the only American man to finish.
"The places you travel and the things you see are amazing," said Rose, who's from Cleveland. "The favorite memories of my life are in these races and with these people."
Of course, not all the venues have such perks.
Australian Brendan Capell, the reigning 25K champion, remembers a vicious storm turning a race in China into a real test of survival.
"We were out there for 10 hours," Capell said. "Really, really bad."
Even when conditions are normal, things are hardly easy.
Food breaks are the only things that interrupt the monotony. In most events, coaches on boats are allowed to deliver power bars and cups of water with sticks. With a carefully timed roll, the swimmers swipe the treats, toss them into their mouths and continue.
In Montreal, swimmers travel around a 2.5-kilometer oval and can drift to one of several platforms for a handoff.
The swimmers say their minds never wander.
"It's really not boring at all," said American Sara McLarty, who competes in triathlons and finished fourth in the 5K. "You're constantly aware of the things around you and the things happening inside of you."
And when the race is over, the competitive nastiness subsides.
"It takes a certain, special kind of person to do open-water swimming and we kind of all have a bond doing it together," said Rose, a 2004 Northwestern graduate. "It's definitely competitive, but you're also wanting every competitor, not just your teammates, to overcome all the challenges and finish the race, too. That's unique to open water."