Insomnia has its perks. Just ask Bellingham endurance runner Daniel Probst, known to some of his friends as "The Danimal."

While other sleep-deprived competitors start hallucinating during the 100-mile or longer running races that are Probst's idea of a good time, his mind remains clear. His body doesn't seem to crave sleep the same way, thanks to the insomnia that used to force him to get by on three to four hours of sleep a night for months on end.

He didn't know then that he was training for ultras, which also are called endurance races.

"I've never hallucinated through a run, no matter how many hours," says the 29-year-old, who's happy running up mountains and down, mile after mile, hour after hour. "That's my strength."

Probst is some kind of Superman, then.

His longest stretch of racing, of just keeping one foot moving in front of the other without benefit of sleep? That would be 46 hours, 40 minutes during the Hardrock Hundred Mile Endurance Run in Colorado in July. Right behind that is the Arrowhead 135 Mile Winter Ultramarathon in Minnesota in February, only because he slept two hours during the 53 hours, 30 minutes it took him to complete the race.

Danimal, indeed.

"The high is just amazing," Probst says of finishing a 100-miler. "A lot of people kind of crash afterward but I just love it. Some people are just made to do things. I guess that's what I was made to do."

RUNNING UP NUMBERS

Ultras are continuous running events that are longer than the standard marathon distance of 26.1 miles. They're broken into lengths of 50 kilometers (31 miles), 50 miles, 100 kilometers (62 miles) and 100 miles. There are even 1,000-mile races.

Instead of distances, some races are defined by hours — 12, 24 and 48 — as well as six days. The goal is to cover as many miles in the specified time as possible.

The sport is increasing in popularity across the country, with notable hotspots such as the Seattle area, according to Dan Brannen, executive director of the American UltraRunning Association.

Brannen estimates the number of runners participating in ultras has grown by about 70 percent in the past 15 years to 12,000 to 14,000.

"(It's) still very small compared to the population of regular road runners," he says.

There also has been tremendous growth in the number of ultra events, according to Brannen, with more than 400 held each year in the U.S.

"The growth is overwhelmingly, almost exclusively, in the area of trail ultra marathons, off-road courses, courses that feature an adventuresome component," Brannen says. "I think a lot of it has to do with the nationwide attention over the past 10 years to 15 years on extreme sports, such as mountain biking and adventure racing. Trail ultra running is perceived by many as a version of that, which is very easy to do.

"You don't have to invest in equipment. You don't have to know how to do multiple sports. All you have to do is put one foot in front of the other," Brannen says.

TWO WHEELS TO TWO LEGS

Before he was crazy about ultra running, Probst was passionate about mountain biking.

He'd been riding a mountain bike since age 15. "I enjoyed mountain biking as it got me further into the woods and back to nature," Probst says.

He loved it so much that he raced what was then called the Iditasport, a 100-mile biking race in Alaska that took him through forests and over frozen lakes and snow.

"That's what got me hooked on ultra events, especially in the cold," says Probst of that race in 2000, in which he placed 16th out of 67 riders.

Although he loved long bike rides — his other accomplishments included riding across Washington state while still a teen and across the country after graduating from high school — Probst had no yearning to run races.

His one experience with it was in high school, when he ran cross-country at Ferndale.

"I had liked running, but running at full force for three miles on hard-packed, flat, wide open trails like you'd find at (Lake) Padden just wasn't my style," he recalls. "I was used to mountain biking on single track in the woods up on Galbraith Mountain. After the season ended I went back to the bike, never thinking I would get back into running."

Then came the winter of 2004-2005, when he was struggling with depression and insomnia and riding less because his mountain bike was old and he didn't have the money to buy a new one.

He decided to run his way out of his slump. "I was just running to get back to nature, to clear my head and to feel that feeling of strength back in my body I had felt when riding," Probst explains.

He ran short distances of five miles once or twice a week by himself but soon felt lonely. So he met up with others during the daily running events organized by Fairhaven Runners & Walkers. He started running with a Thursday night group and liked that they were running on trails.

But then he wanted more of a challenge. So he hooked up with the people who were doing "epic" runs of 1˝ to 2 hours on Wednesday nights.

"We went to Galbraith, a place where I had spent many hours on a mountain bike," he says. "We turned on our headlamps and headed up the mountain."

He remembers thinking the guys were fast and that "they run up the steep stuff." He thinks they ran about nine miles.

"I was more wiped than I could ever remember being before in my life. But I loved every minute of it. I knew at that point this is what I was looking for. So I came back week after week to go run in the dark on real trails. Each week it got just a little easier to hang on."

Bellingham resident Ron Linton remembers meeting Probst the first time he showed up for the Wednesday night runs, saying he was just there until he could get back on a mountain bike again.

"He, obviously, enthusiastically took to running. The first time he came out running with us he was hurting pretty bad," says Linton, 46.

Probst soon learned the guys were training to run the Chuckanut 50K. He trained with them and ran the race. It was his first ultra. He was dead-sick the day before, he says, but still he ran.

"This greatly improved my mood, and I was sleeping better, mostly due to running myself out of energy," Probst says.

"GUNG-HO"

He never looked back. After the Chukcanut 50K, he ran the Stormy, a 64K (39.6 miles) in Canada that summer.

"I was hooked for life," says Probst, a snowmobile mechanic and metal fabricator.

And then he learned about the hundred milers.

"When I heard there were hundred-mile runs that you ran all night, I thought, ‘Oh, I was made for this. Run all night for over 24 hours, I can do that.' "

Some of Probst's friends just shake their heads.

"Our starting line is: Dan's crazy, now what did he do," Linton says with a laugh.

His running friends say that casual can-do attitude is just who he is. He doesn't balk at the thought of running down and up the Grand Canyon or in a race in Colorado featuring a climb the equivalent of scaling three Mount Bakers.

"I think gung-ho probably would cover it," says Karl Jensen, a friend and fellow ultra runner from Vancouver, B.C. "He's very focused. He's very committed. He just keeps plugging along. He sets a goal and he goes for it."

Jensen, 58, is a member of the Vancouver running club to which Probst belongs. He started running ultras in 1990 and just completed his 100th ultra-marathon this month, 24 of them 100-milers.

He compares ultra's latest surge in popularity to that enjoyed by marathoning back in the late 1970s.

"We're at the start of that boom now," Jensen says.

That boom includes interest among younger runners like Probst, although the sport is still dominated by older athletes in their 40s and even in their 50s.

Some attribute the surge to marathoners who're looking for longer-distance runs. Some say it's the beauty that pulls at them.

"At 3 o'clock in the morning, you're out by yourself in the middle of nowhere, everything hurts and you're thinking is this misery going to end, and you're smiling," Jensen says of life on the trails.

"It's just quite amazing, especially if it's a clear night and you're literally out in the middle of nowhere. You look up and you just have this amazing sky. And the silence when you're running alone in the forest…" he adds.

Probst has run 21 ultras since his obsession began about three years ago. Five of those races have covered 100 miles.

He likes running in extremes. High temperatures are OK. Ditto for high elevation. And severe cold? Probst goes for the frosty temps like some kind of running snowman.

"I stay warm when it's cold, no matter how cold it is. I love to run on the snow. It's incredibly peaceful running on the snow. It's quieter. You hear all the little noise — the coyotes, the wolves."

Consider the Arrowhead 135 Mile Winter Ultramarathon in International Falls, Minn., which he started on Feb. 4 and completed in 53 hours, 30 minutes. He placed fifth overall in a race where just 10 runners finished, two of them women.

"(This is) the race where I spent the first day in shorts and spent the second night melting the ice off my shoes — all on less then two hours sleep," Probst says.

Temperatures ranged from 35 degrees during the day to 22 below zero at night. Probst had wanted to run all the way through but had to stop one night because his shoes were frozen. He figured he might as well get a little shut-eye while waiting for them to thaw. And, oh yeah, he was pulling a sled with 30 pounds of gear while he ran.

His other notable achievement is the Hardrock Hundred Mile Endurance Run, which he started on July 13.

Probst finished in 46 hours, 40 minutes, without a wink of sleep in all that time.

How does he do it? He'll say it's because you don't actually have to run the whole way, that it's more efficient to speed walk up hills and then run down. But when he says he's not running, that doesn't mean he's jogging either. Nothing that slow. Just slower than the runs he does on Wednesday nights in town, those two-hour sessions that he calls his "speed workout."

"When I run longer, I run slower," he says.

Probst says this with a laugh, with a shrug. Yes, some people might think it's crazy but it's natural to him. He swears he's not doing it because he likes pain and suffering. Heck, he doesn't even train all that much, figuring that he runs on average about 30 miles per week.

The way he talks, running is about the pure joy of movement, about being out in nature, about running at night with your head lamp on, about that feeling of running through the woods like you're a kid again.

"There's just something about climbing a mountain and being on single track. It's that time after about 30 miles … you just get into a groove, your body starts working good. It's absolutely amazing, the places you get to go and the things you get to see."

That's fun, even at 3 a.m. when he has to fight through extreme exhaustion, just because he can, just because he wants to do it. He's not running for the money, even though he admits it would be nice to get a sponsor or two to help defray the costs of traveling.

"I run because I enjoy it. I haven't got to the point where I want to win anything yet. Because there's a big, big step between doing well and winning. So far I haven't wanted to take that step. It doesn't look fun to me — yet."