High Altitude Mask For Training?

[Bluejeep]

They are more of a gimmick then a training device. Do some HIT training at the gym (High intensity, short duration) and once a week or so so some hills with your pack on and a sandbag. That's what I've started doing and I feel it has made a big difference for me.

But also be prepared to spend some money. Doing all the extra miles with my pack on really showed me how crappy it was and forced me to buy a Kifaru pack