Hummingbird Effect

Hummingbird Effect manga summary: A few generations ago, a mysterious phenomenon occurred. Humans now die after 1.5 billion heart beats; half the heart rate they originally had. Schools began teaching students how to control their emotions and regularly preformed heart rate tests. No one is allowed to use more than the number assigned per week. This is the story of 2 girls that chose to love in this world regardless of their heartbeats.