Below is a sortable list of individuals who died as a result of running a marathon.

The most frequent causes are:

1. sudden cardiac death, triggered by a congenital or acquired heart disorder;
2. exercise-associated hyponatremia or other electrolyte imbalance;
3. exertional heat stroke or severe hyperthermia.

The age distribution ranges widely, from the teens through the sixties.

In 2016, a systematic medical review found that the risk of sudden cardiac death during or immediately after a marathon was between 0.6 and 1.9 deaths per 100,000 participants, varying across the specific studies and the methods used, and not controlling for age or gender. This translates to a few published marathon deaths worldwide in a typical year, although the authors lamented the lack of a central registry for the information.^[1]

The second major risk arises from imbalanced fluid or electrolyte levels, particularly hyponatremia (sodium deficiency, overhydration, or water intoxication). As a marathon medical director described the counter-intuitive and under-publicized risk in 2005: "There are no reported cases of dehydration causing death in the history of world running, but there are plenty of cases of people dying of hyponatremia."^[2]

Heat stroke is an emergency condition in which thermoregulation fails and the body temperature rises above 104 °F (40 °C). It becomes a greater risk in warm and humid weather.^[3]