You need to be fit and determined! Only those who have trained well have a good chance on Mont Blanc. You need to be hill fit, used to long mountain days carrying a pack, and long scrambles over broken mountain terrain. Don't train for the minimum and hope you will get away with it. An ascent of Mont Blanc will probably be the toughest physical effort of your life.

The summit day involves around 12 hours of almost constant exertion at high altitude. This is best trained for by going hill / mountain walking or mountaineering. Working out in a gym is a lot better than nothing but is not a replacement for the real thing. The physical challenges of climbing Mont Blanc can be easily under-estimated resulting in climbers running out of energy and having to turn around on the mountain. It’s not necessary to go very fast on the mountain, but we do need to move consistently for about an hour and a half at a time between brief rest stops. In addition to a high level of general fitness, stamina and determination are also required to climb the mountain with a decent safety margin.

You can find out more about how to prepare for high-altitude here.