With the temperature in Japan soaring well past 30 degrees centigrade and high humidity rates, Wilshere hopes that the tough test will prove fruitful for the future.
"It's so tough," he told the club's official website.
"There's no air and you're struggling to breathe at times. It's going to help us when we get back to England.
"I've been doing a lot of power work when I wasn't able to do the fitness side of things. Power-wise, I'm at the same level as all the other players but fitness-wise I'm a bit behind. But it's coming.
"I got 45 minutes and I felt good so in the next game hopefully I'll get an hour and then get a full game in the Emirates Cup."
The 21-year-old struggled with ankle and foot injuries last season and made just 25 Premier League appearances.
Next up for Arsenal is a clash against the Urawa Red Diamonds in their last match of the tour on Friday before returning home to host the Emirates Cup, which will include Napoli, Galatasaray and Porto.