Many forms of fasting have become popular in recent years due to research supporting its potential benefits for metabolic health. Some people skip food and drink for a certain number of hours á la intermittent fasting, while others exercise on empty, also known as fasted cardio. And while working out without fueling first might provide some payoffs, it definitely depends on your goals, the type of exercise you do, and how your body reacts to working out without food.
Here, we break down exactly what fasted cardio is, the potential pros and cons, and who might benefit most (or least) from the practice.
What is fasted cardio?
Simply put, fasted cardio means you don’t have anything to eat before you engage in physical activity, says Jamie Kyei-Frimpong, MS, FNP-BC, nurse practitioner at Parsley Health. You typically work out first thing in the morning, so you fast overnight for at least eight hours. The cardio itself can range from low intensity to high intensity. Typically, people start out with short bouts of fasted cardio, like 20 to 30 minutes, but others go for even longer.