It is commonly said that once reached a certain age a normal person completely ceases to sprint. While it is untrue, people still sprint under some circumstances but on average it becomes something so rare that there's no conditioning on such extremely high intensity efforts and they can become potentially harmfull.
Like it's the case for Claire that you can see in the picture: she wasted time and she missed the bus to go to her first day at the new job. You can see her running as fast as she can to reach a different station before it's to late. The effort is so heavy that her heart is now beating at 187 bpm, 100% of her maximum heart rate; a rhythm that clearly can't be held for much time, especially given the fact she barely workout at all.
















