Exposing the body to cold causes biological changes that can lead to sudden cardiac arrest.
SCA was found to be high during winter months (in the U.S), where between 167-175 people per 100,000 population suffered. The warmer months only saw 131 per 100,000. Studies also conducted in Germany, Korea, China, Finland and UK showed similar results.
So, why do more people suffer from cardiac arrest during winter months? There are many reasons, but cold weather exposure increases blood clot formations in the body. Therefore, there is an increase in the red cell count, increases in plasma cholesterol and increases in glycoprotein (fibrinogen) which promoted clot formation. Exposure to cold inhibits the increase in protein C which has a protective effect against clot formation.
Source: E Times