There Are Two Types Of Cardio—Here’s Why They Both Matter

Sure, you can deadlift serious poundage and you just ran a 10k, but do you know the difference between aerobic and anaerobic exercise? (It’s OK—it’s not totally obvious.)

Here, we refer to the experts for a breakdown on the two different types of cardio that do a body good.

Aerobic: Moderate impact for sustained use

Aerobic exercise pumps oxygenated blood from the heart to the muscles. It’s powered by oxygen and fat, which is why it’s associated with weight loss, according to the American Journal of Medicine.

Aerobic exertion is typically low to moderate (think: hiking, swimming, or biking at a comfortable pace), which means it can be sustained over a longer period of time. If you can talk while you’re doing it, you are probably doing an aerobic activity.

Dani Urcuyo, Family Medicine resident at the Cleveland Clinic and CrossFit specialist, explains: “Predominantly aerobic exercises have many benefits, including optimizing cardiovascular health, improving mood, and reducing the risk of many chronic disease like diabetes, high blood pressure, and obesity.”

In fact, regular aerobic exercise has been shown to help reduce glycosylated hemoglobin (or blood sugar levels) in patients with type 2 diabetes, according to Sports Medicine, as well as effectively promote mood stability, according to the Journal of Clinical and Diagnostic Research.

Anaerobic: Short, high impact

Anaerobic exercises, on the other hand, can be categorized as high-intensity activities sustained over short bursts of time (hello HIIT class). If you engage in a full-on sprint where you can’t produce enough oxygen to go for a long period of time (hence the shorter intervals), you’re exercising anaerobically. This sort of exercise is also beneficial for weight loss and muscle growth.

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With this form of exercise, glycogen begins to be used as fuel (since there’s not enough oxygen to power the body). With a lower presence of oxygen in the blood during these quick bursts of anaerobic activity, carbohydrates break down in our body and leave behind lactic acid, which causes fatigue and discomfort. This is the anaerobic threshold (a.k.a., the “wall”) you eventually hit when you exercise as hard as you can.

Don’t let the short intervals fool you: Anaerobic exercise offers plenty of benefits: “Anaerobic exercise helps to develop muscle mass, which in turn boosts metabolism,” Dr. Urcuyo says.

In fact, according to one study, a group who did anaerobic exercise after aerobic exercise (versus only performing aerobic exercises) showed the greatest reduction in their body mass index (BMI), according to the World Journal of Cardiology.

The Bottom Line: Go for Both

Think of aerobic and anaerobic cardio as your go-to tag team—both are beneficial for your health. In fact, both energy systems are active when we exercise, but, notes Dr. Urcuyo, “It’s the duration of the activity that dictates the proportion each of these energy systems is active.”

During a 5-K run, for example, the aerobic system is more active than the anaerobic system. But if you hit the track for an hour of 100-meter sprints with short rest periods between each one, then your anaerobic energy system is getting the most use.

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“Nature doesn’t make a distinction between exclusively aerobic or anaerobic exercise,” explains Dr. Urcuyo. “Rather, both systems function on a continuum, and that’s how we should train.” If you alternate short bursts of riding a bike or running as fast as you can in-between a more moderate running or biking pace, you’re engaging in both aerobic and anaerobic exercise.

To get the most out of your exercise routines, Dr. Urcuyo recommends using functional movements as the foundation of a 15-minute workout, three times a week. One workout he suggests: “In 12 minutes, complete as many rounds as possible of 10 deadlifts, five pull-ups, and a 200-meter run.” An additional weight-lifting session can be added for optimized training, and a long run, row, or swim—which counts for aerobic cardio—makes for a great recovery day activity.

Variety keeps our workouts interesting and maximizes the benefits of exercise by engaging different parts of our bodies in different ways. By creating routines that utilize both aerobic and anaerobic cardio, we reap the positive effects of each.

As Dr. Urcuyo says, “Predominantly aerobic and anaerobic exercises should be included in almost everyone’s training, primarily because that’s exactly what life demands of us.”