Which study design describes the investigation into exercise's impact on myocardial infarction risk?

The study design that investigates the impact of exercise on the risk of myocardial infarction is a cohort study. In this type of study, a group of individuals is followed over time to see how exposure to a certain factor—in this case, exercise—affects the development of an outcome, such as myocardial infarction.

Cohort studies are particularly effective for assessing the relationships between exposures and outcomes, as they allow researchers to observe the natural progression of health events in real-time. Participants are categorized based on their exercise levels (e.g., those who exercise regularly versus those who do not) before any instances of myocardial infarction occur. This longitudinal approach helps establish whether a correlation exists between exercise and the risk of heart attacks.

In contrast, other study designs would not provide the same clarity in establishing cause-and-effect relationships. For instance, case-control studies look retrospectively at subjects who already have the outcome and compare them with those who do not, which may introduce recall bias regarding exercise habits. Case series simply report outcomes in a defined group of individuals, lacking a comparison group. Cross-sectional studies provide a snapshot in time without establishing temporal relationships, making it difficult to determine whether exercise influenced the risk of myocardial infarction. Thus, a cohort study is the most