The dependent variable in the experiment given above is THE HEART RATE.
In every experimental set up, there are usually two major type of variable, these are dependent and independent variables. Dependent variable refers to those variable that their values depend on the value of others while independent variable refers to those variable whose values do not depend on any other variable. In the question given above, the heart rate is the dependent variable because its value depend on the type of exercise that a participant undergo.
