User blog comment:FairyRaven/Fairy Tail Chapter 423: Do It All for Love, Review and Commentary/@comment-194.103.203.254-20150309125626/@comment-24038953-20150309180113

To respond to FairyRaven, they are much more like each other than you think.

First, Luffy only trained under Rayleigh for a year and a half, and he was only trained on haki. Whose to say that Gildarts didn't spend time to train Natsu after the chapter where they met up, and it has been shown that Gildarts is one of, if not the most powerful person in Fiore.

Bluenote might have spent time in prison due to him being in Grimoire Heart, and was only released following the Tartarus FT guild war. He wouldn't have been able to train as much in the year due to him also teaching the new guild.

Actually, there is an explanation for not being affected. Gildarts wasn't really affected by it due to his immense physical strength, and it has been shown that Natsu's power has been drastically increased. He has probably reached a point of strength great enough for the change in gravity to not mean much if anything.