For all the cozy scenes pictured in the holiday ads, the Christmas season can be an intensely stressful time. Take the anxieties surrounding money, family, and unrealistic expectations, throw in extra alcohol and sugar consumption, and the most wonderful time of the year can take a toll on physical health.
That stress may have deadly consequences. Researchers in Sweden looked at data on 283,000 heart attacks that took place in the country between 1998 and 2013. (Researchers in Sweden have access to data of this breadth thanks to a national database that collects information on every acute cardiac patient in the country, known by the endearing acronym SWEDEHEART.)
They found, as previous studies of coronary incidents have, that heart attacks happened more frequently in the early morning hours and on Mondays. They also noted that the risk of heart attacks spiked during the holiday season, with a peak at 10pm on Dec. 24—the day when most Swedes hold their Christmas family gatherings, according to a new paper in the BMJ. Heart attacks were 37% more likely to happen on Christmas Eve than during the control period, and 20% more likely on New Year’s Day. Throughout the week between Christmas and New Year’s, heart attack risks were 15% higher than other days in December.
Sweden isn’t the only place where this phenomenon has been identified. In 2004, cardiologists in Los Angeles, California noted an increase in heart attacks and other acute cardiac episodes during the period between Christmas and New Year’s.
Correlation isn’t causation, and researchers pointed out that the risk rates may be affected by factors they’ve overlooked. The patients who experienced an acute coronary incident on Christmas tended to be older than 75, with diabetes or a known history of heart problems. Still, they note, given that previous studies have documented a link between acute stress and coronary incidents, it’s possible that holiday stress does in fact prove fatal for some.