THE EFFECTS OF EXERCISE: A “Chemical Snapshot.” “Exercise-associated changes were seen in more than 20 metabolites, reflecting processing of sugars, fats and amino acids as fuels as well as the body’s utilization of ATP, the primary source of cellular energy. Several changes involved metabolic pathways not previously associated with exercise, including increases in niacinamide, a vitamin derivative known to enhance insulin release.” If exercise were a pill, everyone would be taking it.