Aerobic exercise (also known as cardio) is physical exercise of low to high intensity that depends primarily on the aerobic energy-generating process.[1] "Aerobic" means "relating to, involving, or requiring free oxygen",[2] and refers to the use of oxygen to adequately meet energy demands during exercise via aerobic metabolism.[3] Generally, light-to-moderate intensity activities that are sufficiently supported by aerobic metabolism can be performed for extended periods of time.[1] What is generally called aerobic exercise might be better termed "solely aerobic", because it is designed to be low-intensity enough so that all carbohydrates are aerobically turned into energy.
5. Dunstan DW, Barr ELM, Healy GN, et al. Television viewing time and mortality. The Australian Diabetes, Obesity and Lifestyle Study (AusDiab). Circulation 2010; 121: 384-91. Available at: http://circ.ahajournals.org/cgi/reprint/CIRCULATIONAHA.109.894824v1?maxtoshow=&HITS=10&hits=10&RESULTFORMAT=&fulltext=Dunstan&searchid=1&FIRSTINDEX=0&resourcetype=HWCIT
“This has all been scientifically proven,” says Hall. “Dr Darren James, research fellow at South Bank University, has done a study showing all this. WalkActive significantly and statistically improves your posture, increases your walking speed by up to 24%, reduces joint impact, joint stress at the knee and at the ankle and improves your body shape.” It is, unmistakably, a fitness programme, as in, you would undertake it for the same reasons as an aerobics class, to lose weight, or at the very least, redistribute it in a more sightly way. I did several 10-minute walks, and while never out of breath, was certainly more tired at the end than I would normally have been.
Running is a high-impact exercise so the injury risk is higher than with walking. Common problems include injuries to the knee, shin splints and ankle sprains. If you can, you should aim to run on dirt tracks or grass rather than on the road as this puts less stress on the feet and knees. Runners and joggers need well-fitted running shoes designed to cushion the impact of running. If you’re not normally active, it’s important to start with regular walking first before gradually building up to jogging or running, and speak to your doctor before starting any new exercise program.
Stumped for an idea? Take a quick stroll around the block. Whether you need a solution to a problem at work or you’re looking for inspiration for your novel, walking gets your creative juices flowing in all areas. A recent study published in Frontiers in Neuroscience found that walking improved both convergent and divergent thinking, the two types associated with enhanced creativity.
To achieve a training response, athletes should exercise 3 to 5 times per week for at least 20 to 60 minutes. Fitness level can be improved with as little as 10 minutes of exercise if done 2 to 3 times per day. If the goal is also to lose body fat, athletes should exercise for at least 30 to 60 minutes. Athletes who are not fit will need to start with lesser amounts of exercise. They can slowly add more time as their endurance improves. Increasing the level of exercise at about 10% per week is a good goal to prevent overuse injury.
Walking for 30 minutes a day at moderate intensity is great. Walking for a longer period of time is better still. As you get fitter, you will be able to walk more briskly. Walking up and down hills will also help to boost stamina and leg strength. You’ll get even more benefits from a walk if you swing your arms as this helps you walk faster and can burn 5 to 10 percent more kilojoules.
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! 

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.

Dr. Tannenberg offers another tip for incorporating intervals into your workout: “Create a new playlist with upbeat songs followed by slower songs. Alternate the songs on your playlist. When you are walking and hear a faster song, you increase your pace. When the slower song comes on, you slow down the pace a bit. This is an easy way to make your normal morning walk an interval workout.”
On the other hand, some people like to know with more precision how their body is doing during exercise. If that's the case for you, then taking your heart rate during exercise and using a target heart rate training zone might be just the ticket. Target heart rate zones range anywhere from 50% to 100% of your maximum heart rate (your maximum heart rate is based on your age). Aerobic exercise is anything less than 85%, and anaerobic exercise is anything above that. A nice starting point for a sedentary individual is somewhere in the range from 50% to 65% (you can always increase as you get more fit) and 65% to 85% for more conditioned individuals. 

Surgeon General: The Surgeon General recommends 30 minutes or more of accumulated moderate intensity physical activity on five or more days per week to improve health and fitness. "Accumulated" means you can do it in shorter bouts throughout the day (for example, 10- or 15-minute intervals throughout the day), and "moderate intensity" means you feel warm and slightly out of breath when you do it. You can read more about the Surgeon General's "lifestyle" recommendation at: www.cdc.gov/nccdphp/sgr/sgr.htm.

But it’s not only your creativity that will benefit from the mental lift. The act of walking is also a proven mood booster. One study found that just 12 minutes of walking resulted in an increase in joviality, vigor, attentiveness and self-confidence versus the same time spent sitting. Walking in nature, specifically, was found to reduce ruminating over negative experiences, which increases activity in the brain associated with negative emotions and raises risk of depression.

A single activity can include elements of both aerobic and anaerobic exercise. For example, interval training, where you alternate cycles of low-intensity (aerobic) and high-intensity (anaerobic) work during the same workout, has elements of both. So does a game of tennis where you might sprint at one moment (anaerobic) and then move less aggressively for several minutes (aerobic) as you hit ground strokes from the baseline.

Walking might not have the same visual appeal as high-intensity interval training or step aerobics, but this simple exercise can be an efficient way to burn calories. Whether you're anxious to shed a few pounds or are just keen to avoid the middle-age spread, walking several times per week (in combination with a healthy diet, of course) can burn thousands of calories to help keep the excess pounds at bay. Consult your doctor before beginning any exercise regimen, even a light one.


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.
The American Heart Association recommends that everyone reach a minimum of 30 minutes of some form of cardiovascular exercise 5 to 7 days per week. This can be broken up into 10-minute time periods. This means that taking 3 walks of 10 minutes each would let you reach the recommended minimum guideline for reducing the risk of heart disease, diabetes, hypertension, and high cholesterol. You would also burn the same number of calories as you would if you walked for the full 30 minutes at 1 time.
Impaired aerobic capacity, also known as impaired endurance, is a common patient impairment that can limit participation in functional, occupational, and recreational activities. Even functional tasks that require only a few minutes can be limited by aerobic capacity. Older adults are particularly vulnerable to impaired aerobic capacity due to anatomic and physiological changes that occur with aging, greater propensity for sedentary behaviors, and greater risk for disease processes that limit the oxygen transport system.1 In addition, aerobic capacity is directly influenced by the habitual activity pattern of an individual, which may vary across individuals from total inactivity to frequent and intense activity. Any factors that limit habitual physical activity, such as illness, injury, and or travel, will cause adaptations that diminish aerobic capacity. Conversely, any factors that promote habitual physical activity, such as intentional exercise, yard work, and occupation-related physical tasks, will result in adaptations that improve aerobic capacity. In older adults, many physiological, pathological, and psychosocial factors can contribute to restricted physical activity. Figure 12-1 depicts the persistent vicious cycle that can be created when sedentary behaviors, chronic disease, and functional dependency interact.2 This chapter will provide an overview of causes and factors contributing to impaired aerobic capacity in older adults and describes physical therapist patient management (examination, evaluation, diagnosis, and interventions) to address decreased endurance and its impact on function.

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."
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).
Some might say that walking is the easiest form of exercise. That is untrue because you should not really be strolling but walking at a fairly fast speed and secondly, it can actually help you lose weight. A University of Utah study in 2014 found that in women, every minute of brisk walking throughout the day could lower the risk of obesity by 5%. Harvard School of Public Health found that walking could cut the effects of obesity-promoting genes by half.
Update: the authors removed a sentence about the human body operating on physiology rather than physics. This sentence was in reference to 500kcal exercise not directly relating to the number of grams in 500kcal of fat as determined by typical bomb calorimetry. This is due to the various ways individual physiology treats energy intake and energy expenditure. The authors decided to remove the sentence since it lacked the additional context behind the statement.
The same goes for intensity, too: Hiking or climbing stairs can actually bring your walking METs burn up to running levels. “Greater muscle forces are required to move faster to accelerate the body up and down, move the limbs faster, and work against gravity,” says Hunter. “Running or walking uphill requires a greater energy, just like lifting weights upwards. It’s as if our body is the weight that we must move to greater heights, so the greater the slope, the greater the energy requirement.”
Though the risks of being sedentary far outweigh the risks of exercise, one should be prudent when beginning an aerobic exercise program. Safety guidelines from the ACSM state that individuals at low or moderate health risk can begin a moderate-intensity exercise plan without a medical exam or exercise stress test, whereas people at high risk should be evaluated by their doctor. You are at high risk if you have:
Intensity: On a scale of 1 to 10, with 1 meaning relaxed and 10 thoroughly exhausted, Stein advises starting a walk at level 2 or 3, working up to level 6 to 8, and then cooling down to a 2. "The recommendation is the same for everyone," he says, "because as you get more and more fit, you actually end up having to walk faster or steeper to keep that 6 to 8 up."
“This has all been scientifically proven,” says Hall. “Dr Darren James, research fellow at South Bank University, has done a study showing all this. WalkActive significantly and statistically improves your posture, increases your walking speed by up to 24%, reduces joint impact, joint stress at the knee and at the ankle and improves your body shape.” It is, unmistakably, a fitness programme, as in, you would undertake it for the same reasons as an aerobics class, to lose weight, or at the very least, redistribute it in a more sightly way. I did several 10-minute walks, and while never out of breath, was certainly more tired at the end than I would normally have been.
How to measure progress: Other than simply feeling great and watching the scale, you can actually measure what walking is doing for your body. Before you begin your activity program, have your doctor check your cholesterol, blood pressure, glucose (high levels can be a sign of early or undiagnosed diabetes), and your body mass index (BMI). BMI is a number that reflects your height-to-weight ratio (simply take your weight in pounds, multiply by 703 and divide by your height in inches squared -- keep this number under 25 for optimal health).
Walking also offers plenty of health benefits, including lowering the risk of high blood pressure, heart disease and diabetes; reducing the risk of developing dementia and cancer and even reducing fibromyalgia pain. Plus, walking may be even more beneficial than running. Walkers have a much lower risk of exercise-related injuries than runners, whose legs absorb about 100 tons of impact force in just one mile. So, if you’re just starting your fitness journey, know that fitness walking is a seriously good place to begin.
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