What causes sudden adult death or in there sleep ?

There are many: causes of SCD but most are related to heart conditions such as a weakened muscle, coronary artery disease or genetic abnormalities affecting the electrical aspects of the heart (Long QT).

Many causes: There are literally dozens upon dozens of reasons for dying from both reasons, usually cardiac or pulmonary origins. Heart attacks, collapsing lungs, serious infections, severe allergic reactions, acute trauma, bleeding from a wound in the wrong part if the body, severe overheating or severe cold, old age, the list goes on and on