Exercise Helps the Heart, But Can Manual Labor Hurt? By Batya Swift Yasgur, MA May 12, 2021 -- All exercise is not created equal, and the exercise you get during leisure time is better for your heart health than on-the-job exercise. In fact, on-the-job physical exercise may actually be harmful to heart health, according to a study published in April. The difference in leisure-time exercise and workplace exercise is a phenomenon sometimes called the “physical activity paradox,” lead study author Andreas Holtermann, PhD, of the National Research Center for the Working Environment in ...