It’s well established that cardiovascular diseases are a leading cause of disability and death worldwide, of which coronary artery disease and heart failure are the most common.  Even though there has been great progress in diagnostic and therapeutic strategies for coronary artery disease and heart failure over the past 30 years, the prognosis remains poor, greatly affecting one’s quality of life as well as placing a high burden on healthcare systems worldwide. To reduce the risk for adverse events, such as heart attack or stroke, heart patients are encouraged to participate in a cardiac rehabilitation program that may include patient education, dietary changes, smoking cessation, psychosocial support, stress management, and exercise. While any type of exercise can be considered heart healthy, is there a best type of physical activity for heart patients?

High-intensity interval training (HIIT) is a form of exercise that involves short intervals of near-maximal effort—sprinting or stair climbing, for example—separated by intervals of moderate-intensity exercise—such as jogging or fast walking. In the last decade, several studies have praised HIIT as being as or more effective than traditional moderate-intensity continuous training (MICT) for burning fat, reducing fatty liver, improving blood pressure, staving off cognitive decline, and managing chronic pain.  It's even thought to be beneficial as prehabilitation to reduce the risk for surgical complications and shorten hospital stays. Because a HIIT session takes less time than more traditional exercise routines, patients are more likely to enjoy the process and continue exercising.

In a 2022 systematic review and meta-analysis, researchers reviewed data from 15 studies that included a total of 664 patients with either heart failure or coronary artery disease that compared HIIT and MICT with respect to factors like exercise capacity and specific cardiac measurements. The research team found that over a longer time frame, both forms of exercise are effective for improving prognostic markers like anaerobic threshold and left ventricular ejection fraction. However, participants in the HIIT interventions experienced greater benefits in the short term, suggesting this form of exercise may provide faster results.

For an individual starting a cardiac rehabilitation program who doesn’t enjoy regular moderate-intensity exercise, they should consider HIIT. The trick is to find a form of aerobic exercise you enjoy (walking, biking, jogging, or swimming, for example) and go at it with vigorous intensity for short time frames (30 seconds, for example) separated by periods of lesser intensity. As fitness improves, increase intensity levels and high-intensity interval times or shorten low-intensity periods to get the most from the workout. Of course, this information isn’t just for heart patients. Everyone at all age levels can benefit from increased cardiorespiratory fitness (consult with your doctor before starting an exercise program) as being physically fit not only reduces the risk for adverse cardiovascular events but should they occur, you may be more likely to survive.