New European research has found that the risk of having a heart attack is higher on Christmas Eve and during certain holiday periods than at other times of the year.
Carried out by researchers at Lund University, the Karolinska Institutet, Uppsala University, and Örebro University, Sweden, the new study is believed to be the largest research to date to use heart attack data from a well-known registry to look at whether national holidays and major sports events may play a role in triggering a heart attack.
The researchers looked at the exact timing of 283,014 heart attacks which were reported over a 16-year period in Sweden, setting the two weeks before and after a holiday period as control periods.
Published in the Christmas issue of The BMJ, the findings showed that Christmas was the holiday which appeared to increase the risk of heart attack the most, by 15 per cent compared with the control period, with the risk of heart attack peaking at around 10 p.m. on Christmas Eve, particularly for older and sicker people.
The researchers suggest that as Christmas Eve is the main day of celebration in Sweden, it may be the time when emotional stress also reaches its peak.
Midsummer holidays were also associated with a 12 per cent higher risk of heart attack.
People were also more likely to experience a heart attack early in the morning at 8am and on Mondays.
The increased risk was greater for seniors over the age of 75 and those with diabetes and heart disease.
Perhaps surprisingly, New Year's Eve, which is usually the main day for celebration ringing in the new year, was not associated with an increased risk. Instead people were more likely to experience a heart attack on New Year's Day itself, which the researchers say was "possibly explained by a negligence and masking of symptoms due to alcohol."
Unlike in previous studies, no increased risk was seen during sports events or during the Easter period.
As an observational study, the researchers point out that no firm conclusions can be made about cause and effect and that other factors not included in this study may also be at play.
However, previous studies have shown a rise in heart attacks across the western world during Christmas and New Year celebrations, and during Islamic holidays in Muslim countries. The team also noted that emotions such as anger, anxiety, sadness, grief and stress have also previously been linked to an increased risk of heart attack, as well as physical activity and lifestyle changes, both of which may occur during national holidays.
