While taking their usual bath, the boys discuss how much Kyotaro is like an old man. The next day, when they go to school, they find themselves exhausted by climbing up the stairs... and learn that they're all becoming old men!
No one's around yet, so the room isn't warmed up, 
which lowers their body temperature.
لا يوجد أحد في الغرفةِ بعد، لذا فهي غير
دافئة، ممّا يخفّض درجة حرارة الجسم
Es ist noch niemand da
und der Raum ist daher kalt.
Dans une salle vide,
la température est plus basse,
Visto che non c'è nessuno, la stanza non si è ancora
riscaldata e questo riduce la temperatura corporea.
Ninguém chegou ainda, então a sala não está
quente, o que baixa a temperatura do corpo.
В комнате ещё никого нет,
поэтому воздух тут холодный.