Sports fans who strongly associate with their teams may actually have physiologic response from watching their team win or lose.
Studies have examined male fans attending games with teams that are rivals. The fans provided saliva samples before and after the games, and testosterone levels were checked.
The testosterone level of fans increased the same amount as the players who were actually in the game.
The testosterone levels increased up to 20% in the winners, and decreased about 20% for the losing side!