May 5, 2011 -- Somewhere in the middle of belting out "Total Eclipse of the Heart," Lauren Marks' life changed forever. A cranial aneurysm, silent and symptomless until that fateful night in a Scottish karaoke bar, ruptured, causing hemorrhaging in parts of her brain.
Within hours this 27-year-old graduate student would wake up from emergency brain surgery to find that she could no longer read and could barely speak coherently. The bleeding in her skull had damaged parts of her brain associated with language, leaving her with acquired aphasia, a loss of the ability to use or understand words.
Although smoking, hypertension, being female or having a family history of aneurysms are all chronic risk factors for these abnormal blood-filled bulges -- which can show up in a CT scan -- less is known about what causes a longstanding aneurysm to rupture.
New research from the Netherlands, published Thursday, offers some insight into how certain everyday activities and emotional states, such as having sex, drinking caffeinated drinks and being startled can increase the likelihood of an aneurysm erupting.
A brain aneurysm rupture such as Marks' occurs when a section of brain artery becomes weakened, resulting in stroke or hemorrhaging.
Although the effects of a ruptured aneurysm can be devastating, it's important to remember that aneurysms themselves are somewhat rare: It is estimated that between 2 percent and 5 percent of Americans live with a brain aneurysm, and the vast majority will never experience a rupture. Among those who do, half will die, and half of those who survive will live with permanent disability.
Doctors suspect that a sudden increase in blood pressure puts strain on the wall of an aneurysm, increasing the chances that it will break, says Dr. Khaled Aziz, director of the Center for Complex Intracranial Surgery at Allegheny General Hospital in Pennsylvania.
Thursday's study, which identifies eight activities or states most associated with a rupture, supports this theory: They can all be tied to a sudden spike in blood pressure.
"We want to sort out whether the prescription of anti-hypertensive drugs in persons with [brain aneurysms] may prevent the growth and rupture of these aneurysms," says Dr. Ale Algra, co-author of the study and a neurologist at the University Medical Center Utrecht in the Netherlands.
Doctors have long had anecdotal evidence that certain activities, such as sex or straining on the toilet, were risk factors for ruptures, but this study is the first to assess just how risky these behaviors can be for those who have aneurysms.
The following are the eight routine activities that researchers found to be associated with an increased risk of aneurysm rupture.
Daily Cup O' Joe
Drinking coffee was the risk factor most commonly associated with a ruptured aneurysm, although the study found it increased the likelihood of rupture only slightly. After surveying 250 patients who had aneurysms, researchers found that the odds of a rupture were 1.7 times higher in the hour after drinking a cup of joe.
While the increased risk among coffee drinkers was not huge, the frequency with which most people drink coffee makes it a good target for change, says Algra. For those in the population who know they have an aneurysm -- or who have a family history of aneurysms -- this data suggests that they should refrain from drinking coffee.
Vigorous physical exercise has also been a well-noted trigger for an aneurysm rupture, and Thursday's study found that hard exercise upped risk of rupture 3.5 times. This could mean that those with known, particularly large aneurysms should avoid very hard exercise, but for the most part, doctors believe that exercise shouldn't be excluded.
"The long-term benefits of exercise probably outweigh the short-term risks," says Algra.
Caffeine is most likely the culprit behind the 3.4 increased risk of rupture noted among those who drank soda in the hour before their aneurysm ruptured. Cola may be more apt to ramp up caffeine intake because people tend to drink more of it than they would coffee.
Doctors said that soda may also be on the list of things to avoid for those with known aneurysms.
Sex and Masturbation
Doctors treating aneurysms note that patients often report a splitting headache -- the most common sign of a rupture -- right after sex or while straining to to make a bowel movement, says Dr. Ciaran Powers, assistant professor of medicine at Ohio State University.
Postcoital aneurysm rupture was the most commonly reported trigger by doctors ABC News spoke to, and Thursday's study supports what these doctors have always suspected: Sex is a leading risk factor for aneurysm rupture.
Researchers found that sexual intercourse increased risk of rupture by 11.2 times, while masturbation increased it by 5.9 times.
This doesn't mean that those with aneurysms should declare celibacy. It might be better to manage high blood pressure in other ways, says Aziz.
A Shock or Startle
Although seemingly insignificant, a simple startle was enough to increase risk of rupture by 23.3 times -- the most significant trigger found in the study. There's not a whole lot doctors can advise patients regarding this particular trigger -- "how can you avoid life?" says Dr. James Ausman at UCLA Medical Center.
Staying away from scary movies and fun houses might not hurt though.
Getting Worked Up
Anger was the only emotional trigger of significance, the researchers found. Study participants were 6.3 times more likely to suffer a rupture if they got worked up about something in the hour preceding it.
Anger may also tie into general prevention advice among those at risk for aneuryism. They should limit stress, says Aziz. To Marks, who's an actress and had been on stage countless times before her karaoke performance in Scotland, it seemed unlikely that stress had caused her aneuryism to rupture. "How many thousands of times I've been onstage," Marks recounts, "I don't know why that one time would have been different, but I don't know."
Blowing Your Nose
Blowing one's nose increased the risk of rupture 2.4-fold. Aziz said this was often true as well for coughing, because both activities increase pressure inside the skull, which in turn increases the chance that the weakened artery will burst.
Straining on the Toilet
Last but not least, straining on the toilet while constipated was another common risk factor, both in the study and anecdotally among doctors who treat aneurysms. It was also one of the few that doctors recommend treating in those with identified aneurysms.
"We think it is feasible to advise persons with [brain aneurysms] to refrain from coffee drinking and to use laxatives when constipated," says Algra.
As for Marks, two brain surgeries and tons of speech therapy later, she is essentially recovered. As a writer, she says she notices hiccups in her language processing every day, but that in some ways relearning to read and speak has left her "better than before."
Aside from keeping up an overall healthy lifestyle, she has not been advised by her doctors to avoid any particular behaviors, although given the new findings, she says she might give up coffee.