Fainting may be in our genes, which may explain why keeling over at the sight of blood tends to run in families, according to researchers in Australia.
The researchers located a specific region on chromosome 15 that is thought to be a prime suspect for “vasovagal syncope,” a drop in blood pressure followed by loss of consciousness.
The study “strengthens the evidence that fainting may be commonly genetic,” said neurologist Samuel Berkovic of the University of Melbourne in Victoria, Australia, author of the report published this week in the journal Neurology.
Berkovic’s team interviewed 44 families with a history of fainting, six of them with a significant number of relatives who faint. One family included 30 people in three generations.
What triggered the fainting? Pretty predictable stuff, such as the sight of blood, injury, a medical procedure, pain, frightening thoughts and prolonged standing.
Scientists have been debating whether fainting is genetic, environmental or both. Some suspect fainting may have an evolutionary benefit; falling over and lying still in response to blood loss increase survival chances.
Last year, Berkovic published findings of a study that showed identical twins were twice as likely to share the fainting trait than were fraternal twins. Fainting among nontwin relatives was low, suggesting that the way fainting is inherited is usually not by a single gene.
Other research suggests there may be a genetic link that makes people susceptible to blood phobias, but that substantial environmental factors come into play.
A person may have a predisposition to react strongly to trauma, such as the sight of blood, with a heart-pounding “fight or flight” reaction, then with a counter-reaction that slows down the pulse and blood so much that it causes loss of consciousness.
And there’s nothing like passing out, or watching mom or dad pass out, to teach the brain to fear what brought it on. Phobics may then start reacting in anticipation of giving blood, for instance, dooming them to the same loop of tension-fear-faint. The genetic component, scientists argue, comes only in the fainting part.
So, you probably can thank mom and dad, either way.
The holiest plant of the Christmas season may be a raggedy shrub with peeling bark that seems to grow best in a dusty backyard in Tempe, Ariz. This is Boswellia sacra, better known as the frankincense tree. The shrub’s gum resin is one of the three biblical gifts that the wise men bestowed on the infant Jesus. Until recently, Americans who wished to cultivate their…
FRESNO, Calif. — Federal law now allows visitors to carry guns in national parks, but you can’t just slip a loaded pistol into your backpack and take a hike. Pay attention, because this is a little complicated. You will need a concealed weapons permit to carry the loaded gun in the backpack. But you don’t need any kind of permit if you just want to…
Move over, large lap pools. Smaller swimming holes are making a big splash. Sure, the economy is playing a role in making this luxury littler: Smaller pool equals smaller budget. But it's more than that, says Brett Berry, owner of Landscape Renderings, a Missouri business that designs and builds outdoor living environments. “You can create a fantastic sense of intimacy and atmosphere with a small…
A few weeks ago, a reader sent me an eloquent email complaining about a story in which I'd suggested paddling on the northern branch of Sparks Lake as an alternative to more crowded portions of the popular lake. The writer said that over the decades, he'd seen Central Oregon “loved to death. ” Now, powder is tracked out in 30 minutes, Sparks Lake is always…
A barred owl that drew crowds of onlookers while swooping around at Farewell Bend Park earlier this year may well be dead. The owl was seen from mid-January into last month, regularly hunting for mice and voles along the Deschutes River just upstream of the Old Mill District. It then disappeared about a month ago. Two photographers found a dead owl March 3 about 10…