A good thing about doing sport is that one has lots of erotic dreams. The good thing about having lots of erotic dreams is self evident. And yet it is also a very well known fact that these dreams are rarely fully satisfying. Is that latent dissatisfaction the reason why we always tend to go back for more?
It makes good evolutionary sense that dreams shouldn't completely appease. No matter how good one's power for visualization is, internally generated images can never actually be a substitute for the real thing: as Shakespeare put it, you cannot “cloy the hungry edge of appetite by bare imagination of a feast”. If you could make yourself feel full by thinking of a plate of spaghetti carbonara, you would never bother to get up and go hunting for bacon. But why after sport in particular?
It doesn't make sense, especially for those who were born bankrupt: you lose the match, waste a lot of energy in the process, nobody asks you out (because you are a loser), and then you make a fool of yourself by dreaming the impossible while wasting more calories. And then you go back for more of the same next week. Is it possible instead that we find such talents as doing some sport or other to be attractive in others, because they serve as an externally visible signature of good genes? A marker for a superior product, a sort of 'truth in advertising'. That would mean that it is not actually our own activity that causes the dreaming, but the memory of our sport mates (oh-la la).
The answer is much less contorted. Evolution has no foresight (or hindsight, for that matter). Ultimately it makes no difference to the brain how our reward pathways are activated, as long as they are activated. The desire to be successful (and therefore attractive), the need to follow rituals, to fight, are driven by the same neural activity whether one wins or loses, as long as one fights: the brain uses a carrot-and-stick system to ensure that we pursue and achieve the things we need to survive and spread our genes. The famous four “f”s of our survival instinct: flee, fight, feed or fornicate.
In this way a stimulus from the outside (your opponent) is registered by the limbic system which creates an urge that is consciously acknowledged as desire to whack him/her. However, sport has developed in society not in the environment where we evolved, and therefore requires suprainstinctual application of reasoned deliberation and willpower. That's why, most of the times, a bout does not proceed unchecked toward a murderous frenzy. The brain knows about these supraregulations but doesn't like them.
The activity that follows the feeling of aggression sends messages back to the limbic system which releases opioid-like neurotransmitters which in turn raise circulating dopamine which create a feeling of satisfaction. Or dissatisfaction. In both cases, the loop is activated and does not stop when one goes to bed, because it is here that the brain will try to accommodate one's primeval instincts to modern social dictates.
To the brain, it makes no difference: suddenly deprived of the outside sensory stimulus, in the absence of temporal and spatial limitations (not to speak of the general ugliness of reality) the brain picks up where it left when it was awake and takes it to its logical evolutionary conclusion: hallucinatory mating. The inevitable distortions of a re-play in absentia then make us creative, and et voila': your sexy dream.
Hasta la victoria, companeros. Siempre.
Gianna