[@Stern Algorithm]
Once again, Kanako did as Catherine instructed. She began by taking longer breaths than usual. This was easy enough for her as she had quite  a decent lung capacity. But when she tried the shorter ones, after a while, she felt it was beginning to take its toll on her stamina. It was as if she was not getting enough air inside her lungs.

"Haaa...haaa...haa...haa..." Kanako panted as she returned to her normal breathing pattern. "T-that was... quite tiring..."