You would need data from a large number of people, best from a varied age and gender. For each person you would need pulse rate readings of the person at rest not watching television, watching an unexciting television program and watching an exciting sporting event on television. The pulse rates taken not watching television and watching an unexciting program serve as a control and comparison to eliminate the conjecture that watching any television causes pulse rate to increase. You would also have to be sure that each person is watching a sport that they consider exciting rather than one that you consider exciting, not everyone finds the same things exciting. The larger the body of data you accumulate, the more convincing your argument will be.