Abstract: At 2:45 p.m. on July 11, 2017, an employee was delivering mail on a park and loop city mail route. The carrier parks the mail vehicle, loads the mail satchel with mail and packages, walks to deliver the mail and back to the vehicle to get more mail or move vehicle then load satchel again. The employee collapsed on the porch of a residential mail customer during delivery of mail on the assigned mail route. The autopsy revealed extensive enlargement of the heart with multiple blockages of the arteries of the heart. The manner of death was listed as natural as a result of arteriosclerotic and hypertensive cardiovascular disease. High risk factors for a heat-related injury, due to working in a high temperature and humidity zone in an unacclimatized state after a three week absence from work. Based on the employee's unacclimatized condition after being away from work for three weeks, he was at risk for a heat-related injury which could have contributed to his cardiovascular collapse.