Anyone who’s witnessed the jaw-dropping feats of riders who take to the Whistler Mountain Bike Park has an idea of what kind of guts are involved in zooming down scarily steep descents. But if you’ve ever wondered just how much of a workout riders actually get from blasting straight downhill, just ask Kelli Sherbinin.

The mountain-bike maven and co-owner of North Vancouver’s Endless Biking says there’s a lot more to downhilling than just going with gravity.

“It’s amazing the kind of exercise it is,” says Sherbinin, who teaches a variety of mountain-biking styles and used to race downhill. “Downhill race courses take between four to six minutes to come down, and you are pooped. I’ve never been in such good shape as when I was downhilling. You’re sweating so much; you’re just using everything you can.

“You’re really taxing your muscles,” she adds. “You’re working so hard because you’re standing up, not sitting down, and all your muscles are engaged to adapt to the terrain and to work with the terrain. You need core strength as well.”

The park at Whistler is closed for the winter, but mountain bikers are still on the trails across the region. Winter riding delivers the added challenge of having to pedal up steep hills like those throughout the North Shore in order to come down: it’s a serious workout. And now is the time for downhillers to cross-train.

Meanwhile, a new study out of UBC backs up Sherbinin’s claims about the effort involved in downhilling. Published in the Journal of Sports Sciences in October, it found that downhill biking is associated with significant physiological demands that yield benefits for people’s overall fitness level.

“One of the things that shocked me was that it’s a full-body workout,” says lead researcher Jamie Burr in a phone interview. (The kinesiologist was with UBC’s cardiovascular physiology and rehabilitation laboratory when the study was under way and now works at the University of Prince Edward Island.) “Road biking is mainly a leg workout and a bit of core, but when I’ve done downhill mountain biking I just wanted to let go of the handlebars because my arms were hurting so much.

“According to guidelines of the American College of Sports Medicine and the Canadian Society for Exercise Physiology, this qualifies as a potentially fitness-inducing sport,” he explained. “The demands are anywhere from moderate-intensity to vigorous-intensity exercise, depending on how much people are willing to push themselves.”

While the physiological demands of cycling have been well documented, the study was the first to look at the fitness benefits of downhill mountain biking. The adventurous sport typically involves lift-only access to trails, which can consist of natural obstacles as well as human-made features such as jumps, vertical drops, and banked walls.

“There’s no doubt that you’re working on the way up if you’re riding up a mountain; now we can conclusively say there’s sufficient physical work on the way down too.”

Sherbinin doesn’t race downhill anymore, but she still regularly rides her mountain bike when she’s not teaching, guiding, or toting her infant daughter around. She says the popularity of mountain biking in general continues to escalate, especially among women.

“Women tend to be really analytical, and with mountain biking there’s a lot to think about,” Sherbinin says. “It’s not an easy-peasy sport. You have to put your thinking cap on to navigate the terrain.

“Depending on the discipline, you might be thinking about your heart rate, your pedal strokes, what gear you’re in, how to be more efficient with the way you’re riding, how to stay balanced on the bike through whatever terrain is thrown at you,” she adds. “It really makes you think about what skills you have in your toolkit and what skills you need to go and learn.”

Mountain biking is accessible to people of all skill levels, from elite athletes like Sherbinin to novices. That doesn’t mean the sport is for everyone, though.

“We do recognize the potential risks associated with this sport,” Burr says. “Although we talk about the health benefits from a cardiovascular- and muscular-fitness point of view, people have to be careful with this. There is the possibility of traumatic injury.”

According to a study published in the journal Wilderness and Environmental Medicine in June 2012, fractures, particularly those in the upper extremities, were the predominant type of injury at Whistler’s bike park in 2009, followed by traumatic brain injuries.

“The downhill nature of this type of riding appears to lend itself to falling forward over the handlebars, with the rider landing on an outstretched hand and arm,” the study stated. “Alternatively, riders may fall to the side and use an arm to protect themselves.…Most injuries appeared to involve riders losing control of or falling off their bikes.”

Burr’s study, meanwhile, found other factors that might make people pause before investing in a hard-core mountain bike for downhill riding.

Study participants were found to have significantly elevated heart rates, which could be partly attributed to the effects of the sheer force involved in people’s hand grips to maintain control of their bikes. That spike in heart rate could have serious implications for people at risk of cardiovascular problems and those with heart disease.

But for folks who are comfortable on a mountain bike, regardless of the style they prefer, Sherbinin says the benefits go far beyond the physical.

“It gets you out into the forest, puts you with other people who appreciate the forest, and it makes you giggle,” she says. “It makes you face certain challenges and fears. It teaches you about yourself. Get fit and meet people; it’s a very big community.

“You’re getting out there and you’re seeing beautiful vistas and you’re getting exercise, but the adventure part of it has always been really exciting for me,” she adds. “It helps you discover what you’re capable of. It gives you a feeling of being strong and fit and like you could accomplish anything.”