You are deceived by the fact that Japanese people aren't fully on the obesity bandwagon yet and plenty of them have teenager-like slim builds well into their 40s.
If you look at his hair, it is graying already quite a bit.
He's in his 40s and an ex-maritime self defense force member.
The man is in his life 40s sp certainly not young young
Wow! Well, I guess given Japan's life expectancy of 84, he's got half of his life still.
Life expectancy is counted from birth, not age 40.
That makes it even higher since infant mortality drags down the averages.
Your odds of making it to 84 only go up the older you get.