Hot temperatures are a risk to people and their health, and often lead to health problems and deaths related to cardiovascular disease, such as heart disease and stroke. The objective of this project is to look at how hot temperatures affect the heart health of Canadians. There is limited research focusing on the effect of hot temperatures on morbidity and, where research exists, the findings have been inconsistent, with several studies finding an increased risk for cardiovascular disease-related hospital admissions with high temperatures. By identifying who is at the highest risk, we will be able to add to the information on climate change and its effects on heart disease and stroke. Generating this information is important as, without it, it is difficult to take any action to improve the heart health of people most at risk. Knowing where the greatest needs are will allow governments and health organizations to implement programs that can have a real impact and lower the number of people with heart disease and stroke. By studying how hot temperatures affect emergency department visits, hospitalizations, and deaths for heart disease and stroke, we hope to improve the quality of life of people living with heart disease or stroke and decrease the number of Canadians ending up in the hospital or dying due to hot temperatures.