In reply to llanberis36:
> Would usually go and sit up at the midi
Since actually performing exercise at higher altitude has almost nothing to do with triggering the physiology of acclimatization (with goal of performance at 3500 - 4500 meters temporarily for 7-10 days), just sitting at the top station of the Midi lift is actually the most effective strategy (or perhaps spending a night at Refuge des Cosmiques).
. (and there a couple of tricks of chemistry and physics that help speed up the acclimatization physiology for that sort of goal, but likely you're already including those in your programme).
Ken
Post edited at 00:29