On certain peaks the fatality rates are staggering, but on K2 they are mind-boggling. When a climber straps on his crampons with the intent of ascending K2, he knows he has a one-in-four chance of not making it off the mountain alive. One in four. And as bad as those odds are, they are even worse for women. Six women have reached the summit of K2, but five have died trying. (In addition to the three who died on descent, another two women died on ascent without reaching the summit.) For women the statistics are small but nonetheless powerful. The bottom line is that women have fared disastrously on K2.
Ironically, as bad as their experience on K2 has been, women actually die less often than men on the other 8,000-meter peaks. Although there has been almost no scientific research on the effects of high altitude on the female body, what little data there are actually indicate that women are better suited to the rigors of the Death Zone than their male colleagues. Recent studies suggest that as men and women climb higher, men’s initial advantage of muscle mass and brute strength equalizes out against women’s better endurance and ability to adapt to the thin air. Not only do women suffer high-altitude pulmonary edema less often, but they acclimatize better, they retain their base body weight better, and their more efficient circulatory systems lead them to suffer less frostbite—the formation of ice crystals in the cells that destroys their structure and constricts the oxygen flow, leading to infection and, if untreated, quickly to gangrene, resulting finally in amputation. There is also early evidence that the female sex hormone helps to guard women against the deadly effects of high altitude, but further research needs to be done to make that theory conclusive.
Aaargh, I wish there had been an end note or footnote or other form of reference here. I'd have loved to look up the research behind this.