Some of the blame for Conor McGregor's loss to Nate Diaz at UFC 196 this past March was blamed on his lack of cardio after the Irishman faded in the second round before getting submitted (see it again here). Granted, "Notorious" was already training for a Lightweight title fight against Rafael dos Anjos, but nothing could prepare him for the rigors that came with facing a bigger Homer Simpson man at Welterweight who has cardio for days.
On the heels of McGregor's first UFC loss, his head trainer John Kavanagh fine-tuned his training camp ahead of the rematch.