Most activities can be performed aerobically or anaerobically. For example, you could walk briskly on the treadmill at 3.5 miles per hour and feel warm and slightly out of breath (aerobic), or you could walk very briskly at 4.5 miles per hour and feel very out of breath (anaerobic). The same is true for biking, swimming, dancing, or virtually any other activity. The intensity of the workout determines whether an activity is aerobic or anaerobic, and all you need to do is pace yourself to elicit the type of training you desire.
It should be noted that the MET approach was designed to build a classification system of different activities for research purposes - MET values "do not estimate the energy cost of physical activity in individuals in ways that account for differences in body mass, adiposity, age, sex, efficiency of movement, geographic and environmental conditions in which the activities are performed. Thus, individual differences in energy expenditure for the same activity can be large and the true energy cost for an individual may or may not be close to the stated mean MET level as presented in the Compendium." (as quoted from the main page of the Compendium of Physical Activities)

Imagine that you're exercising. You're working up a sweat, you're breathing hard, your heart is thumping, blood is coursing through your vessels to deliver oxygen to the muscles to keep you moving, and you sustain the activity for more than just a few minutes. That's aerobic exercise (also known as "cardio" in gym lingo), which is any activity that you can sustain for more than just a few minutes while your heart, lungs, and muscles work overtime. In this article, I'll discuss the mechanisms of aerobic exercise: oxygen transport and consumption, the role of the heart and the muscles, the proven benefits of aerobic exercise, how much you need to do to reap the benefits, and more.


Start with the basics: your shoes. Trainers are best, with very flexible soles; too rigid and you won’t be able to feel your entire foot. They should have a boxy front rather than one that tapers, so you can feel every toe. Most trainers are a little bit wrong, and Hall is now developing her own. But, she says, by the time you know what you’re doing, you can wear almost anything.
Walking doesn't burn calories as quickly as a number of other aerobic exercises, including jogging, swimming or riding a bicycle. Walking, however, is a low-impact exercise that is ideal for a wide range of people, including those who contend with joint pain and aren't physically able to perform more up-tempo exercises. If you choose to use walking as your main source of aerobic exercise, set your weekly schedule to allow for a minimum of 2.5 hours of walking.
In normal daily activity, adults cover about 2-3 miles. About 2,000 steps equal a mile. To make walking a beneficial activity, you would need to come up with at least another 4,000 steps in a day. You can find ways to add steps here and there, such as walking farther from parking lots, taking stairs when available instead of escalators and elevators, walking the long way to get somewhere in your office building, walking your children to school, having a walk/talk meeting instead of sitting down in a conference room, or planning a short walk around the block as a break.
Walking programs have generally been studied for effectiveness. The Ottawa Panel recently concluded that aerobic walking combined with stretching and strengthening exercises, education, or behavioral programs is recommended to improve pain relief, functional status, and the quality of life of adult individuals with OA.32 Cycling is another form of aerobic exercise that can be beneficial. Low-intensity cycling was shown to be as effective as high-intensity cycling in improving function and gait, decreasing pain, and increasing aerobic capacity in subjects with knee OA.36 Cycling should be considered for those with arthritis who may have difficulty with a walking program because of joint pain.
Use the 1-to-10 scale of perceived rate of exertion to measure endurance. Think of 1 as watching TV; 10 is gasping for air (you can't go any further). Daily walks, for example, are 5 or even 6-6.5 sometimes. Twice a week, crank it up to 7, 8, or 9 on a steep hill for a few minutes. Now you're burning serious calories and building real aerobic fitness through interval training.
When comparing the results of the most recent National Runners’ Health Study with the National Walkers’ Health Study, researchers found that the energy used for moderate-intensity walking and vigorous-intensity running resulted in similar reductions in risk for high blood pressure, high cholesterol, diabetes and heart disease over the study’s six year period.
Your body’s immune system should function properly at all times to prevent infections, diseases, and death. Walking is a great way to boost your immunity. Walking at least 30 minutes a day can help bolster the activities of the immune cells, namely, the B-cells, T-cells, and the natural killer cells (13). It helps release the WBCs at a faster rate, thereby allowing your body to heal quickly (14).

Taking a walk alone can be great for clearing your head or blowing off some steam but it also provides a great opportunity to bond with friends and family—far away from electronics and other distractions at home. Even better, you set a powerful example because when they see you reaping in the benefits of walking, they’ll be encouraged to walk more, too, according to a study published in Psychology of Sport and Exercise.  Try these walking workouts that will keep your walking group interesting.
At the other end of the spectrum, walking can also help meet children's health needs, says Charles Corbin, MD, author of the NASPE's physical activity guidelines. "Kids need to expend enough calories during the day to maintain desirable weight," he says. "Plus, they need to expend energy consistent with building bones and muscles for fitness and normal growth and development."

A higher percentage of fat is burned during aerobic exercise than during anaerobic exercise. Here's why. Fat is denser than carbohydrate (fat has nine calories per gram and carbohydrate has four), and so it takes more oxygen to burn it. During aerobic exercise, more oxygen is delivered to the muscles than during anaerobic exercise, and so it follows that a higher percentage of fat is burned during aerobic exercise when more oxygen is available. When less oxygen is present, like during anaerobic exercise, a higher percentage of carbohydrate is burned.
Your heart beats approximately 60-80 times per minute at rest, 100,000 times a day, more than 30 million times per year, and about 2.5 billion times in a 70-year lifetime! Every beat of your heart sends a volume of blood (called stroke volume -- more about that later), along with oxygen and many other life-sustaining nutrients, circulating through your body. The average healthy adult heart pumps about 5 liters of blood per minute.
Can you up those numbers? The more you weigh, the more calories you’ll burn, no matter the activity—that’s because it takes more energy to move more weight. If you’re specifically looking to up calorie burn, adding a 20-pound weighted vest would up your calorie burn to 8.7 and 15.1 per minute for walking and running, respectively. It’s simple physics: “The majority of calories burned in running [or walking] comes from supporting body weight while moving up and down,” says Hunter. “With more weight, there will be a greater energy cost in doing this due to a greater gravitational force.”

Whatever your preferred exercise intensity, it’s also important to choose activities that you enjoy and will stick with over the long term. Walking, biking, hiking, dancing, and gardening are all great forms of aerobic exercise that you can easily integrate into your day. After all, aerobic exercise can greatly improve your health even if you perform it in shorter segments throughout the day.
Their conclusion was the same as the plea issued by the Surgeon General: "Every U.S. adult should accumulate 30 minutes or more of moderate-intensity physical activity on most, or preferably all, days of the week." The researchers determined that intermittent as well as sustained activity can be beneficial. In other words, on days when you can't fit in a 30-minute walk, you can still garner fitness benefits by taking two or more shorter walks squeezed in throughout the day. This may seem somewhat confusing to those of you who are well acquainted with previous recommendations to exercise for a sustained period of 20 to 60 minutes. The Surgeon General's report is not meant to overshadow or replace these previously recommended exercise guidelines.
And when equal amounts of energy were expended (meaning walkers spent more time exercising), one study found runners still lost more weight.Greater weight loss from running than walking during a 6.2-yr prospective follow-up. Williams PT. Medicine and science in sports and exercise, 2013, Nov.;45(4):1530-0315. In this study, not only did the runners begin with lower weights than the walkers; they also had a better chance of maintaining their BMI and waist circumference.
Sedentary lifestyles have repeatedly been held partially responsible for the excessive poundage. This is why many groups, including the American Heart Association (AHA), the National Association for Sport & Physical Education (NASPE), and AARP, are now promoting campaigns on how to incorporate physical activity into daily life. And since these organizations recognize the challenge of getting people moving, many have included fitness walking into their recommendations.
The last thing I noticed, was how much walking helps with the writing process. There’s been research into this, too; into the synchronicity between walking and writing. Joyce walked, Wordsworth walked; so did Virginia Woolf. Dickens used to walk 20 miles a day, which makes me feel… competitive. Walking, researchers believe, helps with memory and promotes new connections in the brain. It definitely shifts whatever writer’s block I have ever experienced; if I ever get stuck: I just go for a walk. Walking always fixes it.
High intensity interval training, which involves alternating periods of intense effort with recovery periods, can help you blast away calories. In 2014, researchers for the journal Applied Physiology, Nutrition, & Metabolism found that a 20-minute high intensity interval training workout boosted metabolism just as much as 50 minutes of cycling at a steady pace during the 24 hours following the exercise. In the study, participants in the interval training group cycled at a sprint pace for 60 seconds and then recovered for 60 seconds following each sprint. Add high intensity interval training to your routine to increase your metabolism in less time!
Classes are great for people who like to exercise with others, who like to dance, who like music and rhythm, who want the extra motivation and energy that an instructor and class provides, and who prefer the structure and schedule of a regular class. Classes, equipment, and videos are all great ways to stay fit and healthy, but if you're limited by injury or other conditions, then aerobic exercise chair workouts may be just the thing (see resources for online vendors). The instructor leads you through a workout in a chair and it's great exercise. You might not need chair exercise, but you may have a parent or friend who does. Exercise videos and DVDs make great gifts!
A sedentary lifestyle has led to an exponential growth of one of the most common diseases – diabetes. Scientists recommend no less than 5,000 steps a day with more than 3,000 of those steps being a brisk walk – to help manage type 2 diabetes (8). Walking every day can help control the blood sugar levels, which, in turn, can help you prevent type 2 diabetes.

I recommend using a pedometer, or better yet, one of the newer wearable fitness trackers, to keep track and find out how far you normally walk. At first, you may be surprised to realize just how little you move each day. Tracking your steps can also show you how simple and seemingly minor changes to the way you move around during the day can add up. Plus, it’s motivating to see your steps increase throughout the day, which makes it easier to push yourself a little farther to reach your 10,000-step goal.


Walking programs have generally been studied for effectiveness. The Ottawa Panel recently concluded that aerobic walking combined with stretching and strengthening exercises, education, or behavioral programs is recommended to improve pain relief, functional status, and the quality of life of adult individuals with OA.32 Cycling is another form of aerobic exercise that can be beneficial. Low-intensity cycling was shown to be as effective as high-intensity cycling in improving function and gait, decreasing pain, and increasing aerobic capacity in subjects with knee OA.36 Cycling should be considered for those with arthritis who may have difficulty with a walking program because of joint pain.
Sedentary lifestyles have repeatedly been held partially responsible for the excessive poundage. This is why many groups, including the American Heart Association (AHA), the National Association for Sport & Physical Education (NASPE), and AARP, are now promoting campaigns on how to incorporate physical activity into daily life. And since these organizations recognize the challenge of getting people moving, many have included fitness walking into their recommendations.
The heart has four chambers that fill with blood and pump blood (two atria and two ventricles) and some very active coronary arteries. Because of all this action, the heart needs a fresh supply of oxygen, and as you just learned, the lungs provide it. Once the heart uses what it needs, it pumps the blood, the oxygen, and other nutrients out through the large left ventricle and through the circulatory system to all the organs, muscles, and tissues that need it.
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