Mt Whitney Zone Forums General Discussion Acclimatization: how long does it last?

This is a question for those of us "normal" ;)folks that are affected by AMS.

I'm planning on spending night at the Bancroft trail head (11600 ft) and summit the White Mountain 14k+ ft next day. Then rest 2 days and summit Whitney. My question is how long does the acclimatization effect last?

When I summited Whitney on 7/9 for the first time this year, I had hard time from the trail crest on.

One more thing... do people usually deal with the altitude better from second time on?

Thanks for your help. :)