Multiple choice general knowledge science & technology Most heart attacks occur between the hours of ... and ... AM. 4 and 5 AM 6 and 7 AM 7 and 8 AM 8 and 9 AM Reveal answer Fill a bubble to check yourself D Correct answer Explanation Most heart attacks occur between 8-9 AM due to the natural morning surge in blood pressure and cortisol levels. This is part of the body's circadian rhythm that increases cardiovascular stress in the morning hours.