What Counts as Aerobic Exercise? Here’s Everything You Need to Know About How to Get the Cardio You Need

Medically Reviewed
woman running outdoors wearing purple
Aerobic exercise, or cardio, makes you more efficient at delivering oxygen to the rest of the body, helps heart health and lung function, and more.Ivan Gener/Stocksy

Whether you call it aerobic, cardiovascular, or endurance exercise, you’re probably talking about the same thing: getting your heart pumping faster and oxygenated blood flowing, with the goal of improving your cardiorespiratory fitness. But it benefits more than just your heart.

The technical definition of aerobic exercise is “any form of exercise or activity that uses the aerobic metabolism — meaning oxygen is heavily involved in the cellular reactions that provide the body with the energy necessary to perform activity,” explains Michael Jonesco, DO, an associate professor of internal and sports medicine at The Ohio State University Wexner Medical Center in Columbus. “You’re making yourself more efficient at delivering oxygen to the rest of the body.”

That means aerobic exercise makes the heart more efficient and capable of moving more oxygen-carrying blood with every beat. The lungs adapt to take in more oxygen, and the muscles become more efficient at using oxygen.

Another way to think about aerobic exercise, or cardio, is that it's the type of workout that increases your heart rate and breathing but not so much that you feel like you need to stop and rest after a short period of time. Think running, speed-walking, stair-climbing, cycling, and swimming, among other activities.

RELATED: A Complete Guide on How to Start Exercising

Aerobic Exercise Boosts Heart Health and Your Entire Cardiovascular System

Cardiovascular fitness is defined by your capacity to exert yourself, says Nicole Belkin, MD, the chief of orthopedic surgery and rehabilitation and regenerative medicine at NewYork-Presbyterian Hudson Valley Hospital in Cortlandt Manor, New York. “Regular physical activity trains the cardiovascular system to expand the level of demand and increase its capacity. This results in increased blood flow and blood volume to the heart.”

When you’re doing aerobic exercise, cells throughout the body increase the number and size of mitochondria, the microscopic powerhouses of a cell. Mitochondria use oxygen to create energy that can fuel important reactions throughout the body, Dr. Jonesco explains. They make up the part of the body’s cells that turn oxygen into the energy each cell uses to function, according to The Cell: A Molecular Approach.

These changes yield major heart health benefits, with research published in The American Journal of Cardiology showing that aerobic training is the most efficient mode of exercise for improving cardiovascular health.

Regular aerobic exercise helps lower your cholesterol, control blood sugar to reduce your risk of type 2 diabetes, improve immune function, and lower high blood pressure (hypertension), Jonesco says. And those heart benefits are important considering that cardiovascular disease is the leading cause of death for adults in the United States, according to the Centers for Disease Control and Prevention.

“The heart is a muscle that benefits from a workout just like any other muscle in the body. Aerobic exercise, which includes activities like brisk walking, running, swimming, and biking, conditions the heart to pump blood more efficiently to the whole body,” says Eduardo Sanchez, MD, MPH, the chief medical officer for prevention at the American Heart Association.

RELATED: Research Finds Strength Training May Be Underestimated in Promoting Heart Health

Aerobic Exercise Benefits Your Mood, Your Waistline, Your Posture, and More

The many health benefits of aerobic exercise, however, don’t stop with your heart, says Dr. Sanchez: “Physical activity can help manage body weight, lower blood pressure, decrease LDL ("bad") cholesterol, improve blood sugar control, reduce stress, and improve sleep and memory.”

Here’s what the evidence shows:

  • Mental Health Benefits Getting moving boosts your mood. In a study of 1.2 million people published in September 2018 in The Lancet Psychiatry, exercisers enjoyed about 1.5 fewer days of poor mental health compared with nonexercisers.

    While all exercise improved mood, the biggest benefit came from team sports, cycling, and gym and aerobic workouts. Aerobic exercise has been shown to reduce the risk of anxiety and depression in adults; it helps people manage stress via sleep and mood-regulating benefits, according to the Anxiety & Depression Association of America.

  • Weight Loss Benefits Aerobic exercise burns up calories, which in combination with a healthy diet, can help you burn fat and shed excess weight, Jonesco says. Cardiovascular exercise can be part of an effective weight management strategy for those who have obesity, per StatPearls. Aerobic exercise also tones your muscles and improves posture.
  • Fitness Benefits Aerobic exercise (over time) gives you more energy to work out, which can set the stage for an overall healthier lifestyle. By improving your body’s ability to take in and use oxygen for fuel, aerobic exercise can increase your stamina, giving you more energy for both work and play, Jonesco adds.
  • Bone and Joint Benefits Moderate- or vigorous-intensity aerobic exercise like running or jumping rope can help increase bone density in older individuals and for those with osteoarthritis or other rheumatic conditions, notes the U.S. Department of Health and Human Services (HHS).

     
  • Brain Health Benefits Physical activity has been linked to lower risk of dementia and may improve cognition as you age.

Guidelines Say You Should Be Getting Some Aerobic Exercise Most Days, and More if You Can

According to the most recent Physical Activity Guidelines for Americans, published by the HHS in 2018, aerobic exercise varies by three components:

  
  • Intensity How hard a person works to do the activity, such as moderate (the equivalent of brisk walking) and vigorous (the equivalent of running or jogging) pace
  • Frequency How often a person does aerobic activity
  • Duration How long a person does an activity in any one session

According to the HHS, to maintain fitness, adults should aim to get 150 minutes to 300 minutes of moderate-level physical activity or 75 minutes to 150 minutes of vigorous-intensity aerobic physical activity a week. The HHS notes that it is preferable to spread this activity throughout the week on most days.

In addition to this recommendation for aerobic exercise, the HHS recommends performing balance and stretching activities to enhance flexibility as well as muscle-strengthening workouts that target large muscle groups (such as body weight or weightlifting) two or more times a week. All of these components are part of a well-rounded fitness routine.

The World Health Organization also recommends the same duration of weekly aerobic activities, as well as strength exercises for the major muscle groups twice weekly, according to recommendations published in 2020.

This is in line with the American Heart Association recommendations for exercise, too.

RELATED: New Physical Activity Guidelines Say We Should Be Moving All Day Long

Yet data published in the HHS guidelines report shows that nearly 80 percent of adults are not meeting the key standards for both aerobic and muscle-strengthening activity, which contributes to 10 percent of premature mortality.

Types of Aerobic Exercise and How to Get Started

Before beginning any exercise program, especially if you have heart or other health issues, talk to your doctor.

If you’re not doing much aerobic exercise at all currently, Sanchez says that beginners can “start small and work your way up.”

He suggests building in opportunities for movement throughout the day, such as a 10-minute break to walk or do a few jumping jacks. Many people find success in focusing on walking as their exercise and gradually increasing time spent walking to reach the recommended 30 minutes per day on most or all days of the week, says Sanchez. As you gain aerobic fitness, you will be able to increase your exercise intensity.

As the names would imply, the difference between moderate-intensity exercise and high-intensity exercise is the intensity of the workout, or the degree to which you’re pushing yourself.

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How to Do Moderate-Intensity Aerobic Exercise

You’re exercising at a moderate intensity if you can keep up a conversation during the activity. To determine if you’re there, you should be able to get out three or four sentences in a row without gasping for air. It’s a sign that you’re maintaining an intensity that is truly aerobic, meaning aerobic metabolism is supplying the vast majority of your body’s energy, Jonesco says.

Your heart rate should be roughly 60 percent of your maximum heart rate. To find your max heart rate, subtract your age from 220. Multiply that number by 0.6 to obtain your target heart rate for moderate-intensity aerobic exercise, Jonesco says.

How to Do High-Intensity Aerobic Exercise

If you’re active and healthy, and have already built up a base level of aerobic fitness, you can shoot for a higher target heart rate, up to 80 or even 90 percent of your maximum heart rate, Jonesco says.

At this intensity, you will likely be able to say a couple of words before becoming out of breath and needing to gasp for air. You may not be able to talk at all. Keep in mind, however, that intensity predicts duration, so you won’t be able to keep up this intensity for as long as when you’re exercising at lower intensities.

High-intensity interval training — alternating between bouts of all-out effort and low-intensity recovery — is a great way to improve cardiovascular fitness when you’re short on time, Jonesco adds.

Examples of Aerobic Exercises

You have lots of options when it comes to getting your aerobic exercise in, so set a goal to try activities that you enjoy. Depending on your preferences and abilities, aerobics, walking (outside or on a treadmill), bicycling, hiking, aerobic dancing, rowing, and gardening are all quality forms of aerobic exercise that you can easily integrate into your day and can yield big benefits even if you’re doing them in small spurts.

A study published in the European Journal of Applied Physiology showed that exercisers who broke their aerobic workouts into 10-minute bouts throughout the day improved their arterial stiffness, a marker of cardiovascular health, even more than those who performed the same amount of daily aerobic exercise but all at once.

The thinking has also changed somewhat on whether there’s a threshold minimum workout duration required to improve aerobic fitness and reap cardiovascular health benefits from aerobic activity. The most recent HHS physical activity guidelines eliminated the long-standing recommendation that exercise had to last at least 10 minutes to count toward your daily total. The new guidelines emphasize that small bouts of activity throughout the day can add up to big health benefits. Even five minutes counts.

 

Additional reporting by K. Aleisha Fetters, Nicol Natale, and Jessica Migala.

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