On May 19, 2003, Peggy Foster was 7,700 metres up the south side of Mount Everest when she started gasping for air. She was outfitted in a Russian-made breathing apparatus to help her manage the rarefied atmosphere, but it wasn't creating a proper seal on her face to allow the vital mix of life-giving oxygen and ambient air.

In her first attempt at the world's highest peak, Foster was a mere 1,150 metres from the summit. At that moment, as she struggled to breathe, the climber knew that instead of making her final push to the roof of the world, she was about to make her descent to base camp, abandoning months of training and preparation, 60 days of acclimatizing on the mountain slopes and tens of thousands of dollars in expedition fees. "I could have kept going," she recalls, "but I had to do what was optimal, which was to turn around. And that was hard, because it was a piece of equipment, not me, that failed."

"People don't fail because they can't achieve their goals. They fail because they stop just short of achieving them."

Such a monumental setback would crush the spirit of most ordinary people. But Foster, 44, has made a life of overcoming the challenges that define elite athletic endeavours. Rather than representing the end of her dream, the frustrating retreat was merely a bump in the road to becoming the first Canadian woman to climb the fabled Seven Summits - the highest peaks on the world's seven continents. "The most self-limiting trait we have is to let fear control our lives," she says. "If you go through your fears and address them, they get smaller. If you turn around and ignore them or walk away from them, they generally get bigger."

Born in Sault Ste. Marie, Ont., Foster grew up in Ottawa, the daughter of a federal Member of Parliament. She was the only girl in a family of four children and was a self-described tomboy. "I was never treated differently from my brothers," she says. "I had a lot of freedom in what I thought I could do." She proved herself capable of great physical challenges, first with endurance running, then as a marathoner, a competitive Ironman triathlete, an ultra-distance runner and a rock climber. At the age of 34, mountaineering and the lure of pursuing peaks across the globe captured her imagination. "When I climb, I get more clarity," she explains. "There are moments of truth I can't deny."

TOP: Peggy Foster. ABOVE: The Mount Everest expedition of 2003. (Photo courtesy Borge Ousland)

In the scant decade since she took up mountaineering, Foster, who is the mother of a 16-year-old son, has achieved six of the sacred Seven Summits. Since 1997, she has climbed North America's Denali (a.k.a. Mount McKinley), 6,194 metres; the 6,962-metre-high Aconcagua in South America; Europe's giant Mount Elbrus, 5,633 metres; Kilimanjaro, 5,963 metres, in Africa; Antarctica's Vinson Massif at 4,897 metres; and 2,230-metre Mount Kosciusko in Australia, which she added to her list two years ago. (Since Canadian Pat Morrow's groundbreaking Seven Summit quest some 20 years ago, debate has raged in climbing circles about whether the 4,884-metre Carstensz Pyramid in Indonesia or Mount Kosciusko rightly represents the Australian continent's highest peak.) "Persistence is a big thing we need to instill in ourselves," Foster says. "Most people don't fail because they can't achieve their goals. They fail because they stop just short of achieving them."

And Foster views her initial Everest setback as an apt life lesson that merely serves to fire her determination to try again. Having raised the $40,000 (U.S.) she needs to finance the expedition, she'll return this spring to the base of the 8,850-metre mountain to tackle the North Ridge. "I'm going back and will attempt to achieve that goal, yet I don't think I'll be a better person if I make it," explains Foster. "There's been beauty in the longer journey, and that will make the achievement much more satisfying.

— Alec Ross