©Daxiao Productions / Adobe StockSure, people do cardio exercises to lose weight, but there are all kinds of reasons to pursue this sort of exercise — everything from lowering your risk of dementia and diabetes to experiencing the glory of a personal best in a 10k run.
This article explains what it takes to reap cardio exercise benefits — in other words, what type of exercise counts as cardio. It introduces you to terms such as aerobic, anaerobic, and target heart-rate zone.
Comparing aerobic and anaerobic exercise
Aerobic exercise is any continuous, repetitive cardio exercise that you do long enough and hard enough to challenge your heart and lungs. To get this effect, you generally need to use your large muscles, including your butt, legs, back, and chest. Walking, bicycling, swimming, and climbing stairs count as aerobic exercise.Movements that use your smaller muscles, like those leading into your wrists and hands, don’t burn as many calories. Channel surfing with your remote control can certainly be repetitive, sustained, and intense — particularly when performed by certain husbands — but it burns very few calories.
Aerobic means “with air.” When you exercise aerobically, your body needs an extra supply of oxygen, which your lungs extract from the air. Think of oxygen as the gasoline in your car: When you’re idling at a stoplight, you don’t need as much fuel as when you’re zooming across Montana on Interstate 90. During your aerobic workouts, your body continuously delivers oxygen to your muscles.
However, if you push yourself hard enough, eventually you switch gears into using less oxygen: Your lungs can no longer suck in enough oxygen to keep up with your muscles’ demand for it. But you don’t collapse, at least not in the first three minutes. Instead, you begin to rely on your body’s limited capacity to keep going without oxygen. During this time, your individual muscles are exercising anaerobically, or without air.
Anaerobic exercise refers to high-intensity exercise like all-out sprinting or very heavy weight lifting. After about 90 seconds, you begin gasping for air, and you usually can’t sustain this activity for more than three minutes. That’s when your body forces you to stop. You may still use large muscle groups, but you do so for only a short burst of time, and then you need to take a break before starting the next burst.
Running a 30-minute loop around the neighborhood is aerobic, whereas doing all-out sprints around the track with a two-minute break between them is anaerobic. Both count as full-body cardio exercises because they challenge your heart and lungs and burn lots of calories.
You also may do hybrid activities referred to as “stop-and-go” sports, such as basketball, soccer, and tennis. These activities involve long periods of slow, sustained movement with some short bursts of high-intensity activity mixed in.
Warming up and cooling down
Automobiles are built to go from 0 to 60 miles per hour in mere seconds and to stop practically on a dime if necessary; humans aren’t. With any type of physical activity, whether it’s walking, playing basketball, or cross-country skiing, you need to ease into it with a cardio warm-up exercises and ease out of it with a cool-down. (Weight-training workouts also require a warm-up, although they typically don’t require a cardio cool-down.)Warming up
A warm-up simply means three to 15 minutes of an activity performed at a very easy pace. Ideally, a warm-up should be a slower version of the main event so it works the same muscles and gets blood flowing to all the right places. For example, runners may start with a brisk walk or a slow run. If you’re going on a hilly bike ride, you may want to start with at least a few miles on flat terrain. Be aware that stretching is not a good warm-up activity.People who are out of shape need to warm up the longest. Their bodies take longer to get into the exercise groove because their muscles aren’t used to working hard. If you’re a beginner, any exercise is high-intensity exercise. As you get more fit, your body adapts and becomes more efficient, thereby warming up more quickly.
Many people skip their warm-up because they’re in a hurry. Cranking up the elliptical machine or hitting the weights right away seems like a more efficient use of time. Bad idea. Skimp on your warm-up, and you’re a lot more likely to injure yourself. Besides, when you ease into your workout, you enjoy it a lot more. A trainer we know says, “If you don’t have time to warm up, you don’t have time to work out!”
What exactly does warming up do for you? Well, for one thing, a warm-up warms you up — literally. It increases the temperature in your muscles and in the tissues that connect muscle to bone (tendons) and bone to bone (ligaments). Warmer muscles and joints are more pliable and, therefore, less likely to tear.Warming up also helps redirect your blood flow from places such as your stomach and spleen to the muscles that you’re using to exercise. This blood flow gives you more stamina by providing your muscles with more nutrients and oxygen. In other words, you tire more quickly if you don’t warm up because this redirection of blood flow takes time.
Finally, warming up allows your heart rate to increase at a safe, gradual pace. If you don’t warm up, your heart rate will shoot up too quickly, and you’ll have trouble getting your breathing under control.
Cooling down
After your workout, don’t stop suddenly and make a dash for the shower or plop on the couch. (If you’ve ever done this, you’ve probably exited the shower with a hot red face or dripped sweat all over the couch.) Ease out of your workout just as you eased into it, by walking, jogging, or cycling lightly. If you’ve been using a stationary bike at Level 5 for 20 minutes, you can cool down by dropping to Level 3 for a couple of minutes, then to Level 2, and so on. This cool-down should last five to ten minutes — longer if you’ve done an especially lengthy or hard workout.The purpose of the cool-down is the reverse of the warm-up. At this point, your heart is jumping and blood is pumping furiously through your muscles. You want your body to redirect the blood flow back to normal before you rush back to the office. You also want your body temperature to decrease before you hop into a hot or cold shower; otherwise, you risk fainting. Cooling down prevents your blood from pooling in one place, such as your legs.
When you suddenly stop exercising, your blood can quickly collect, which can lead to dizziness, nausea, and fainting. If you’re really out of shape or at high risk for heart disease, skipping a cool-down can place undue stress on your heart.
How to gauge your level of effort
Whether you're doing cardio exercises at a gym or getting at-home cardio exercise with no equipment, you'll need to know how much effort to put in. The question is: To reap the benefits of cardio exercise, just how much huffing and puffing do you need to do? The answer is not as much as you probably think.
©Bojan / Adobe StockSure, you don’t burn many calories from walking on the treadmill at the same pace that you stroll down the grocery store aisles; they don’t call it working out for nothing.
On the other hand, exercising too hard can lead to injury and make you more susceptible to colds and infections; plus, you may get so burned out that you want to set fire to your stationary bike. Also, the faster you go, the less time you can keep up the exercise. Depending on what you’re trying to accomplish, you may gain just as much, if not more, from slowing things down and going farther.
To get fit and stay healthy, you need to find the middle ground: a moderate, or aerobic, pace. You can find this middle ground in a number of different ways. Some methods of gauging your intensity are extremely simple, and some require a foray into arithmetic. This section looks at the two most basic ways to monitor your intensity.
To learn a more precise way to gauge your exertion rate by measuring your heart rate, as well as much more about cardio exercise, check out our book Self-Care All-in-One For Dummies.
The talk test
The simplest way to monitor how hard you’re working is to talk. You should be able to carry on a conversation while you’re exercising. If you’re so out of breath that you can’t even string together the words “help me, Mommy!” you need to slow down.On the other hand, if you’re able to belt out tunes at the top of your lungs, that’s a pretty big clue you need to pick up the pace. Basically, you should feel like you’re working but not so hard that you feel like your lungs are about to explode.
Perceived exertion
If you’re the type of person who needs more precision in life than the talk test offers, you may like the so-called perceived exertion method of gauging intensity. This method uses a numerical scale, typically from 1 to 10, that corresponds to how hard you feel you’re working — the rate at which you perceive that you’re exerting yourself.An activity rated 1 on a perceived exertion scale would be something that you feel you could do forever, like sit in bed and watch the Olympics. A 10 represents all-out effort, like the last few feet of an uphill sprint, about 20 seconds before your legs buckle. Your typical workout intensity should fall somewhere between 5 and 8. To decide on a number, pay attention to how hard you’re breathing, how fast your heart is beating, how much you’re sweating, and how tired your legs feel — anything that contributes to the effort of sustaining the exercise.
The purpose of putting a numerical value on exercise is not to make your life more complicated but rather to help you maintain a proper workout intensity. For example, suppose you run 2 miles around your neighborhood, and it feels like an 8. If after a few weeks running those 2 miles feels like a 4, you know it’s time to pick up the pace.Initially, you may want to have a perceived exertion chart in front of you. Many gyms post these charts on the walls, and you can easily create one at home. After a few workouts, you can use a mental chart. The following table shows a sample perceived exertion chart.
Perceived Exertion
| Scale | Description |
| 10 Maximum effort |
It’s nearly impossible to continue. You’re completely out of breath, your heart is pounding, you’re sweating profusely, and you’re unable to talk. |
| 9 Very hard effort |
It’s very challenging, though not impossible, to maintain activity. You’re breathing hard, your heart is pounding, you’re sweating a lot, and you can barely talk. |
| 7–8 Vigorous effort |
You’re on the edge of your comfort zone. You’re short of breath, your heart is beating hard, and you’re sweating, but you’re able to speak short sentences. |
| 4–6 Moderate effort |
It feels like you can keep moving for quite a while without having to stop. You can have short conversations even though you’re breathing heavily, your heart is beating fast, and you’re sweating. |
| 2–3 Light effort |
It feels like you can keep moving with very little effort for a long time. Your heart rate is somewhat elevated and you may be sweating lightly, but you can breathe easily and hold a conversation. |
| 1 Very light effort |
You’re doing something that requires virtually no physical effort — sedentary activities such as watching TV, riding in a car, or working on a computer. |