Calvin's new issue of Chewing magazine tells how to set up a fitness regime. Calvin says they recommend interval training. He tells Hobbes it's a grueling workout, but you build strength and endurance. Hobbes rolls his eyes and says all the glory makes it all worthwhile. Calvin says you also develop "chewer's jaw", which drives the girls wild.

Calvin's mouth is hanging open. He tells Hobbes he's doing stretches. As he pulls his cheeks and jaws, he says you should warm up before chewing gum. Neglecting to stretch is a leading cause of chewing gum injuries. Hobbes asks about falling down while chewing and walking. Calvin puts on a helmet saying that with a good helmet, the risk is surprisingly small.

Calvin's new Chewing magazine reviews gum chewing apparel. There is a jersey that wicks away perspiration. There is a mesh collar for ventilation and zippered pockets to hold spare gum. Hobbes asks why it's covered with logos. Calvin says that gives a psychological edge of pretending you're sponsored. Hobbes wonders how you tell if you're reading an advertisement, a product review, or the product itself.

Calvin says he needs a heart rate monitor to make sure he's chewing at his aerobic threshold. He wants to see he's chewing more gum, faster, harder, and longer. Hobbes asks the point of attaching a number to everything you do. Calvin says if your numbers go up, you're having more fun. Hobbes calls it science to the spirit's rescue once again.