I think you might be right...He climbed to the base-camp of the Himilays last year...(whatever that is)...he has quite a regime he goes through before these excursions...
Probably a lot of high altitiude training, dealing with the lack of oxygen is really difficult. I do not mean to trivialize trekking, far from it. Technical climbing may have higher physical requirements and allow you to reach everywhere, but that comes with a much higher risk of injury.