There have been recent studies done on this. Check out this article from Time magazine.
Exercise, especially vigorous exercise, can stimulate hunger. As your body burns more calories, it wants you to replenish them!
Other studies have found a link that the more people exercise, the more they think they can eat. Often underestimating how many calories they burned and how many they’re eating. Psychologically they think that all the exercising they’re doing gives them the ok to eat more! Thus, they’re hungrier! This is a common problem, and often spoken about, amongst endurance athletes.