Joshua lost his IBF, WBA and WBO heavyweight titles as he was knocked down four times before a seventh-round stoppage in New York – one of boxing’s biggest upsets.
The pair will fight again in Diriyah, Saudi Arabia on 7 December.
“Boxing was always the easiest part for me. The struggle was always keeping my life in check,” Joshua, 29, told AFP.
“There will be no aftershock after the first fight. I will be smarter. Getting knocked down was good.
“I have made some drastic changes, lifestyle stuff. Family, circles, what is important, priorities. The effort it takes to stay on the straight and narrow is challenging.”
The pair faced off on Thursday during an international media tour for the rematch with Ruiz – who fights under a Mexican flag – wearing a sombrero throughout the news conference.
Joshua vowed to regain his titles and insisted “stopping isn’t in my DNA”.
“As long as I have breath in me I will keep on fighting for the passion of boxing,” said Joshua.
“I faced defeat as an amateur in my third fight. If I had stopped then there would be no now. I lost in the European quarter-finals. If I stopped then, there would be no now.
“Everyone in this room has been through certain things where no-one believed in them.
“I am not gun shy and I am looking forward to getting back in there and regaining my belts.”
The bout has attracted criticism since it was announced it would be in Saudi Arabia.
Human rights organisation Amnesty International has highlighted the country’s “abysmal” human rights record. Heavy restrictions on freedom of expression and women’s rights have been raised, as has the use of the death penalty for offences not recognised as crimes under international law.
The Kingdom has sought to stage sporting and entertainment events in a bid to attract visitors and move away from its oil-dependent economy.
Joshua said: “I have heard it [criticism of Saudi Arabia’s human rights record] ever since the fight was announced. It’s a point of conversation but it’s a good thing that we are talking about it and they are acting on it to make a change.
“They are making good changes and after having these types of conversations, I start realising that yes, there is an issue there. My trips to the Middle East have been to Dubai and I have had fun. The reception has been good.”
Speaking to DAZN, promoter Eddie Hearn said: “We cannot ignore the potential for boxing in the Middle East. I think this is a changing of a guard in many respects. Every promoter in boxing tried to get to Saudi Arabia for a mega event.
“Not just Saudi but Dubai, Abu Dhabi and Qatar will be bidding for fights in future. You either embrace the change or turn your back on it and be an idiot.”
McCracken ‘flack’ and no New York return
Following the defeat at New York’s Madison Square Garden, Joshua said he favoured a return to the American city until the lucrative offer to bring the fight to Saudi Arabia was confirmed.
“It was part of the plan [to fight in New York again]. That was my preferred option,” Joshua said.
His shock defeat in June – the first of the Briton’s career – led to some calls for Joshua to part company with Robert McCracken, who has trained him since his teenage years.
“It was a pretty tough night,” McCracken said. “I don’t think Anthony was himself that night but that looks like an excuse as Ruiz was fantastic on the night. We know he will be better prepared.
“I took flack for the loss, I have no problem with that as the head coach. I wouldn’t have said do the rematch if I didn’t think Anthony could get his titles back. Anthony’s sole mission is the belts back.”
Article courtesy of BBC Sport
Photo courtesy of Ed Mulholland/ Matchroom Boxing