For many non-Irish, who are not exactly sure what St. Patrick’s Day is supposed to commemorate (and for many Irish who presumably do know the roots of the holiday), St. Patty’s is best celebrated at the local pub overindulging Jamison’s and Guinness with green-haired fun loving mates in a mutual state of inebriation.  If you awake the next morning with a hangover, and this is your annual tradition, a new study shows that you have doubled your risk of suffering a brain stroke.  One hangover/year is all it takes, according to researchers at the Institute of Public Health and Clinical Nutrition at the University of Eastern Finland. 

The effects of alcohol on the brain are complicated.  Research shows that light alcohol consumption may provide a protective effect on the cardiovascular system, but heavy drinking increases the risk of disease.  But how much is too much?  Moreover, the way alcohol is consumed is just as important to consider as how much alcohol a person drinks.  Sipping wine all evening provokes a different physiological response than downing shots in rapid succession, even if the total amount of alcohol consumed is the same.  Studies have shown that binge drinking in particular increases the risk of cardiovascular disease, for example.

The new study examined 2466 men in Finland over a 15.7 year period.  The results showed that the risk of suffering a brain stroke was more than doubled in those who reported having one or more hangovers/year.   Brain stroke can be a serious disorder, leading to sudden life-altering disability or death.  Even after correcting for other known risks for stroke, such as age, smoking, cholesterol levels, cardiac disease, etc., a single hangover a year significantly increased the risk of stroke to over twice that of people who reported no hangovers/year according to these researchers.   “The study shows that at least one hangover a year is related to an increased risk of ischemic stroke in men,” the researchers conclude.

Unfortunately the study included no women or elderly, and only people of one race were involved.  Another possible issue is that the data rely on self-reporting, and definitions of what a hangover is can vary among individuals.  Underreporting could also skew the results.  Nevertheless, the biological mechanisms underlying the increased risk of stroke following binge drinking are quite clear.  They include increased blood pressure during heavy alcohol consumption, changes in cholesterol, reduced blood flow to the brain, abnormal heartbeat (atrial fibrillation), and many other biochemical and toxic effects on brain tissue.

So enjoy the Guinness and green, but don’t press your luck on St. Patty’s Day by greeting the next day with a hangover.

The study by S. H. Rantakomi and colleagues is reported in Acta Neurological Scand.  (2013) 127:186-191.

This article was first published on my Psychology Today Blog