Monday Morning Is No Longer Peak Time for Cardiac Arrest Monday mornings used to be the peak time for people to have a heart attack. Not anymore. A new study shows that cardiac arrests are most commonly reported in the afternoon. The study also found that Monday was not the day when most heart attacks happen anymore. There was a small spike in Sunday incidents. The changes might have to do with our updated 24/7 lifestyle and better reporting on when the cardiac arrests happened. How aware of you about your heart health? What precautions have you taken to help minimize the chances of a heart attack?