Abstract
Official guidelines from the Centers for Disease Control and Prevention assert that the majority of health benefits from physical activity are obtained by walking 2 miles (3.2 km) briskly most days of the week (the energy equivalent of running 8 to 12 km per week). The objective of our study was to examine the dose–response relation in women between risk factors for coronary heart disease, particularly the concentration of high-density lipoprotein (HDL) cholesterol, and vigorous exercise at levels that exceed the official guidelines.