This is an interesting article that claims, based on research performed on climbers at Everest Base Camp (EBC) and after their climb that those with lower levels of anxiety had a higher rate of summiting (and a high altitude achieved):
Perhaps not surprisingly, those with high levels of anxiety did not, on average, make it as high up the mountain as those who reported they were relatively calm. Specifically, “each point decrease on the 22-point anxiety scale increased a climber’s odds of summiting by 25 percent,” writes lead author Greg Feldman, a research psychologist at Boston’s Simmons College.
The more interesting point is how they found that the opposite was true for rock climbers:
Conversely, a prior study linked anxiety with performing well in a rock-climbing competition. Feldman and his colleagues write that while fear may be helpful in that sort of short-duration exercise (it can keep the mind sharp and help climbers avoid accidents), these benefits “may be outweighed by costs that may become evident in longer, high-altitude climbs,” such as “distress-related physiological depletion.”
The other interesting item is the small reward motivation…staring up at a summit that is 6,000 feet above you isn’t necessarily motivating for most people. But reaching the next ledge, or the next camp, or crossing or conquering the crux…these smaller goals provide less of a moving target and more of a risk reward system that makes continued progress more manageable.