Five minutes alone with a beautiful woman can cause men so much stress it can damage their heart, new research suggests.
And men trying to court an attractive stranger they believe is not even "in the same league" can suffer an anxiety rate akin to jumping out of a plane.
Researchers from Spain's University of Valencia have reported on an experiment in which they asked 84 unsuspecting male students to share a space with beautiful young women.
The men were paid 16.50 to take part in a psychology experiment and then led into a room and given a Sudoku puzzle to solve.
They were then left alone with another person they understood was also taking part in a puzzle-solving experiment.
After five minutes the researchers took mouth swabs and saliva samples from the male subjects and then measured their cortisol levels.
The researchers discovered that cortisol levels stayed the same when two men were together but rose when a man was left alone with a woman he perceived as attractive.
The team concluded that "for most men the presence of an attractive woman may induce the perception that there is an opportunity for courtship".
"While some men might avoid attractive women since they might think they are 'out of their league', the majority would respond with apprehension and a concurrent hormonal response," the researchers said.
Small increases in cortisol give bursts of energy but in high quantities the hormone can cause stress and increase the risk of heart disease.