Aerobic vs. Anaerobic Exercise: The Differences & How Often To Do Each

We know that regular exercise is key to good health. From blood pressure regulation to weight management and even disease prevention, movement offers research-backed benefit. And doing some exercise is always better than doing none. That said, is anaerobic or aerobic exercise more effective?

Aerobic exercise, also known as endurance or cardio activity, is defined by the American College of Sports Medicine (ACSM) as any activity that uses your large muscles in a rhythmic manner and can be maintained continuously. 

Engaging in aerobic activities increases your cardiovascular endurance, strengthens your heart, and improves your body's ability to use oxygen efficiently.

Research also shows1 that aerobic exercise can reverse and prevent cardiovascular disease, reduce the risk of chronic diseases, improve cholesterol, and aid in weight management when combined with a balanced diet.

So, how can you know if you're in an aerobic zone? One option is to keep tabs on your heart rate during exercise using a heart rate monitor. Aim for a heart rate between 60 and 80% of your maximum heart rate during aerobic activities. No heart rate monitor? You can also use rate of perceived exertion (RPE) to measure intensity level. 

Anaerobic exercise involves short bursts of intense activity, pushing your muscles to work without oxygen.

This type of training promotes muscle growth, increases strength, and enhances power and speed. Research indicates1 that anaerobic exercise can boost fat metabolism, improve insulin sensitivity, and support weight loss. Anaerobic exercise may also benefit the cardiovascular system. 

To engage in anaerobic exercise, focus on high-intensity, short-duration activities that leave you breathless. If you can't sustain the activity for more than a minute or two, you're likely in the anaerobic zone. 

Again, your heart rate tracker can help you estimate when you're in this zone. "In the absence of having a VO₂ max test completed in an exercise science or sports performance lab and understanding your true max heart rate and lactate and ventilatory thresholds, everyday athletes can estimate their aerobic and anaerobic zones using heart rate data from a wearable tracker," says Reed. "For instance, WHOOP defines the anaerobic zone as 80% of your max heart rate or higher (zones four and five)." 

Although most people associate aerobic exercise with cardiovascular health1, cardiologist Michael Twyman, M.D., says there isn't a clear winner because both types of exercise offer distinct and complementary benefits. 

Aerobic exercise enhances cardiovascular endurance and overall stamina. From a health perspective, aerobic exercise can help lower blood pressure and improve lipid profiles for cholesterol management. Anaerobic exercise improves heart strength by building a stronger heart and enhancing its pumping efficiency. Anaerobic exercise also increases VO₂ max, the body's ability to use oxygen during intense exercise. 

Both aerobic and anaerobic exercise have been shown to improve mood and reduce depression2. "Aerobic exercise has been traditionally associated with endorphin release3 and stress reduction," says Nicola. "While anaerobic exercise, particularly strength training, has been linked to improvements in mood and self-esteem." 

Studies suggest5 that engaging in regular aerobic activities like brisk walking or jogging can increase life span. However, a combination of aerobic and anaerobic exercises provides comprehensive health benefits and can contribute to longevity by reducing risk factors for chronic diseases. 

Exercise has short- and long-term effects on hormones and cortisol levels3. Exercise physiologist Alyssa Olenick, Ph.D., explains that both aerobic and anaerobic exercise will increase cortisol (the stress hormone) as this is a general response to exercise. However, the response will be higher for high-intensity training and long-duration aerobic exercise. 

"It's not that one's better or one's worse than the other. It's that people misuse or abuse the intensity of cardiovascular training," says Olenick. "People tend to have too much HIIT or too much moderate- to hard-intensity training all the time and not enough of the lower-intensity aerobic training that's more recoverable and not as stressful on your body to be doing." 

The key, says Olenick, is to balance training intensities across the week, especially for those who do a lot of higher or even moderate volumes of cardiovascular activity and to consume adequate energy (food) to support training. 

The ACSM and CDC recommend that all healthy adults aged 18 to 65 participate in moderate-intensity aerobic physical activity for a minimum of 30 minutes five days per week or vigorous-intensity aerobic activity for a minimum of 20 minutes three days per week. The Physical Activity Guidelines (PAG) also recommend that adults participate in resistance training for a minimum of two days per week.

"Exercise prescription always depends upon the individual and what works for their short- and long-term health and performance goals," says Reed. "But generally, we want to think about meeting the PAG as your first benchmark—at least two days of resistance exercise weekly (technically anaerobic if you are lifting appropriate loads) and at least 150 minutes of moderate-intensity cardiovascular (or 75 minutes of vigorous-intensity cardiovascular) exercise per week."

If you're doing more training volume across the week than the PAG, Olenick says you want most of your training to be aerobic, lower intensity, and then some of your training each week (around 20 to 30%) to be that high-intensity, short-duration exercise so you can balance the intensities and recover properly. 

Research has indicated that combined aerobic and anaerobic training (concurrent training) may improve aerobic performance8 more than aerobic training alone. High-intensity interval training (HIIT) is an example of concurrent training.

"Combining anaerobic and aerobic training in HIIT provides both cardiovascular and muscular benefits in less time," says Nicola. "It can be more engaging and diverse than steady-state workouts and may lead to significant improvements in endurance, strength, and weight loss." 

On the flip side, Nicola adds that concurrent training comes with a higher risk of injury due to the intense nature and, therefore, might not be suitable for everyone, particularly those with certain health conditions. HIIT can also lead to overtraining or burnout without proper rest and recovery. 

High-intensity interval training has become so colloquialized that many people don't truly understand what it actually is and isn't. The ACSM defines HIIT as alternating between periods of very high-intensity work (performed at 80% maximum heart rate or higher), followed by varying periods of recovery performed at 40-50% of maximum heart rate—or total rest. 

"True HIIT is very difficult and uncomfortable and is meant to stress and train your anaerobic energy pathways. What we tend to see more often in the group fitness or digital fitness areas are better described as interval training," explains Reed. "Rather, they're staying in heart rate training zones 3, 4, and 5, alternating between higher intensity work and steady state moderate intensity work—never returning to the 40 to 50% actual recovery between 'all out' efforts." 

Both anaerobic and aerobic exercise can support a number of health goals—from increasing strength to staving off cardiovascular disease. Most of the literature on exercise physiology suggests that doing a mix of both is the most effective way to train.

Experts recommend doing anaerobic exercise (i.e., weightlifting, running) two to three times a week for 20 minutes at a time and aerobic exercise (i.e., jogging, swimming) three to four times a week for 30 minutes at a time. This is a good place to start, though the ideal workout regimen will vary from person to person. And any physical activity is better than none!

Doing both types of training may also reduce your risk of injury. Doing too much anaerobic activity without balancing it out with more sustainable aerobic activity can lead to injury, burnout, and hormonal imbalance. While you can do anaerobic and aerobic training in the same HIIT-style workout, doing this too often can lead to burnout and injury.

The Physical Activity Guidelines (PAG) for Americans is very clear in stating that the benefits of physical activity far outweigh the risks for all people. However, Reed advises that there are some best practices to be mindful of. 

"Gradual progression is key with any exercise program. Doing too much too soon can not only increase the risk for injury or cardiac event, but it can also become less enjoyable, making it harder to sustain positive exercise behaviors long term," she says. 

If you have been told not to engage in vigorous-intensity training, consult a doctor or exercise physiologist before starting a structured training program. "If you have uncontrolled heart disease, hypertension, or other cardiometabolic diseases, working with a certified exercise physiologist can help mitigate the risk and ensure you're responding appropriately to the new-to-you-stress of exercise," adds Reed.