The Duke Activity Status Index (DASI) is a validated questionnaire developed in 1989 as a practical tool to estimate functional capacity in patients, particularly those with cardiovascular disease. Functional capacity is a key determinant of health outcomes, influencing both quality of life and prognosis, especially in populations undergoing cardiac evaluation, preoperative assessment, or management of chronic disease.

Traditional assessment methods, such as treadmill exercise testing or cardiopulmonary exercise testing, provide precise measurements of exercise tolerance but are resource-intensive, costly, and sometimes impractical in routine care. The DASI provides a simple alternative by linking self-reported ability to perform daily tasks with estimated peak oxygen consumption.

The DASI includes 12 activities, ranging from basic tasks (e.g., dressing, eating, walking indoors) to more physically demanding actions (e.g., climbing stairs, sexual activity, or recreational exercise). Each activity is assigned a weight corresponding to its energy expenditure, with total scores ranging from 0 (unable to perform any activity) to 58.2 (full capacity). Higher scores correspond to better functional status and greater VO₂ max.