Mogens (pronounced like "bones") Jensen is a former elite athlete and Iron Man competitor. As a chronic asthma sufferer, he is determined to summit Everest without supplemental oxygen. Mogens is a schoolteacher turned professional mountaineer from Denmark — a country with no mountains.

Asthmatic Mogens Jensen will attempt to climb Everest without supplemental oxygen for the fourth time this year. Last year, on entering the Death Zone, Mogens was hit by altitude sickness. He was so dizzy and nauseous he was afraid he would not be able to negotiate the climb down. A month later he tried again and failed for the fourth time. “I think there must have been a small cerebral thing, too," he says. "I had blurry vision and was off balance for almost two weeks after coming home."

On arriving home, Mogens also discovered that his fiancée had left him. But he’s back again and determined that this year will be his year. Is he dangerously obsessed? Russell wants him to abandon his ambition to climb without oxygen and is growing increasingly frustrated with him. Mogens plans to go faster and lighter and ahead of the main pack on the mountain.

Mogens’ weekly training includes biking 300 - 400 miles (500-600 km), running 60 miles (100 km), lifting weights and walking with a 150-pound backpack.

Meet the Dane with asthma who is determined to summit without supplemental oxygen