It's long been said that pretty women are hard on men's hearts -- country musicians can attest to that.

But a new study says one-on-one contact with an attractive female might also be harmful to men's health, raising stress hormones to dangerously high levels.

And when men are in the presence of a beautiful stranger they view as "out of their league," the risks are even higher, with cortisol levels rising so high that heart attacks and strokes become real possibilities, the Spanish researchers found.

"This is another case of hard science proving the obvious," Toronto-based psychiatrist Irvin Wolkoff, who was not involved with the study, quipped to CTV's Canada AM.

For the study, researchers at the University of Valencia tested 84 male students by asking each one to sit in a room and solve a Sudoku puzzle. Two strangers, one male and one female, were also in the room.

When the female stranger left the room and the two men remained sitting together, the volunteer's levels of the stress hormone cortisol did not rise. However, when the volunteer was left alone with the female stranger, his cortisol levels rose, as measured by a saliva swab.

In some cases, the levels rose so high, researchers compared them to those experienced when someone jumps out of an airplane.

The researchers explain that "for most men, the presence of an attractive woman may induce the perception that there is an opportunity for courtship."

"This study showed that male cortisol levels increased after exposure to a five-minute, short social contact with a young attractive woman. It provides evidence that interpersonal interaction can influence the secretion of cortisol," they write.

Wolkoff says it all boils down to evolution. Since cavemen days, men have been hardwired so that when they see an attractive woman, their cortisol response kicks in to tell men to seek out that woman for mating purposes.

Even though today's man is sophisticated and enlightened, Wolkoff says underneath, he's still "Mr. Ogg from the cave." When he sees an attractive female, he feels stress about wanting to mate with her, and worrying about whether she might already have a mate or be unresponsive.

"So by definition, sexual encounters are in the same general category as fighting or fleeing. These are stressful situations," he says.

Toronto-based sexologist Jessica O'Reilly says she thinks that the physiological wiring of men's brains is certainly at play in these responses. But so are sociocultural factors.

"Men are taught to value women for the way they look. That's kind of our cultural capital in the mating game, where women are expected to be attractive and attract mates with our bodies," she told Canada AM.

"So of course, there's the evolutionary evidence, but there are also just the cultural notions of what makes the woman valuable."

Wolkoff says there's nothing wrong with feeling cortisol or andrenaline in small doses. But he says if elevated levels are sustained over extended periods of time, stress can be very unhealthy.

"Adrenaline can give you high blood pressure, coronary artery disease, etc. Cortisol impairs the immune system. So if you maintain elevated levels of cortisol long enough, you will develop infections, you might even develop malignancies," he says.

"It's not good to be overstressed for too long. So you need to get out of that room with the beautiful woman pretty quickly," Wolkoff says.

"But that's not to say that being around beautiful women is going to induce heart attacks or high blood pressure," adds O'Reilly.

"We wouldn't want this kind of study to be used to argue that women should cover up, or that men can't be productive in the presence of beautiful women. Absolutely they can. We just need to kind of reframe our thinking so that we don't just see women as one-dimensional."