The first time I heard the words "aerobic" and "anaerobic" exercise was in my elementary school health class around the time we had "the talk" (we girls later received packets of pads and powder fresh deodorant; I'm not sure what the boys got, but I'll leave that to your imagination). Though I knew oxygen had to do with what set the two types of activity apart, the difference never really stuck. If you're curious, too, let's take a deeper dive with the help of Miho J. Tanaka, MD, associate professor of orthopedic surgery and director of the women's sports medicine program at Johns Hopkins Hospital.
Dr. Tanaka explained to POPSUGAR that our bodies have several ways to convert food into cellular energy that, in turn, allows for muscle activity. One, she said, is the aerobic pathway that "requires the presence of oxygen. This type of pathway is commonly found in type I, or slow-twitch, muscle fibers, which are used for sustained, lower-intensity activities such as walking and cycling." (Generally speaking, anything that's cardio is considered aerobic exercise, she said.) Anaerobic activity, in contrast "does not require the presence of oxygen. This pathway is found in type II, or fast-twitch, muscles fibers, which typically provide explosive, high-intensity activities for a short duration of time . . . approximately 30 seconds." This includes interval training, sprinting, and weightlifting. HIIT, Dr. Tanaka noted, can be a mix of both: "It is unique in that it is designed to be a combination of aerobic and anaerobic exercises."
Dr. Tanaka further explained that each muscle has both types of fibers (slow-twitch and fast-twitch), activated depending on the exercise you're doing. "For example, long distance running would recruit the slow-twitch muscle fibers that are used for endurance-type activities, while sprinting would recruit the fast-twitch muscle fibers that constitute anaerobic activities."
What Are Anaerobic and Aerobic Exercise Good For?
Aerobic activities that require endurance are good for cardiovascular fitness and weight loss, which according to Dr. Tanaka "has been shown to decrease risk of cardiovascular diseases such as heart attack, hypertension, and stroke." She emphasized running as an example. Anaerobic exercises like weightlifting "are often thought of as being helpful in improving explosive muscle power and strength. It's become popularized in terms of interval training and high-intensity workouts due to its ability to increase strength and muscle mass." We also know that HIIT, specifically, is proven to help reduce fat.
"Although, any activity level can increase your metabolism and contribute to weight loss to some degree," Dr. Tanaka said. "A combination of both aerobic and anaerobic are needed, particularly in athletes." Her last tip? No matter what kind of exercise you're doing, try to prevent injury by properly warming up, stretching, and "avoiding sudden increases in activity levels." And, remember, diet is an important factor whether you're trying to lose weight or gain muscle. Now go get your workout on!