Your birthday is the yearly returning day associated with a roughly 22 percent increase in the chance of having a heart attack. A population-based study in Ontario, Canada, compared emergency-department admissions on people’s birthdays with the number expected on an ordinary day. It found 97 acute myocardial infarction admissions on birthdays versus 80 expected, an increase of about 21 percent, commonly rounded to 22 percent.
The finding does not mean that a birthday directly causes a heart attack, or that every person faces the same increase. Researchers were observing a statistical association in a large population. Possible explanations include emotional excitement, stress, disrupted sleep, heavier meals, alcohol, physical exertion, or postponing medical care until after a celebration. The study also reported increases in stroke and transient ischemic attack admissions on birthdays.
This fact is sometimes confused with research about holidays such as Christmas, sporting events, or a surgeon’s birthday. Those studies examine different populations and mechanisms. A birthday-related increase is a population-level pattern, not a personal medical prediction; established risk factors such as smoking, high blood pressure, diabetes, and cholesterol remain far more important.