Cardio Crash Course

When you’re hanging out with people who exercise a lot you hear the word cardio all the time.  Cardio – which in medical jargon  is short for cardiovascular exercise, means “for your heart.”  It is the kind of exercise that strengthens your heart and lungs and burns a lot of calories.

There are literally dozens of reasons to pursue this sort of exercise – everything from eliminating that spare tire, to lowering your stress level and blood pressure.  Once you understand the basic concepts involved in cardio exercise, you can better design a workout program based on your goals.

How hard do you need to push yourself?  Maybe not as hard as you think.  No, you will not benefit much from walking on a treadmill at the same pace you stroll down the store aisles; they don’t call it working out for nothing.  On the other hand, exercising too hard all of the time can lead to injury and make you more susceptible to burn out.  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 down a little and going longer.

To get fit and stay healthy, you need to find the middle ground: a moderate or aerobic, pace.  You can find this in a number of different ways.  Some methods of gauging your intensity are extremely simple, and some require a bit of arithmetic.  Here are a few of the most popular ways to monitor your intensity.

The talk test.  This is the simplest way.  You should be able to carry on a conversation while you’re exercising.  If you’re so out of breath that you can’t say, “help me!”  You need to slow down.  On the other hand, if you’re able to belt out your favorite song 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 hard enough to breathe hard, but not so hard that you think your lungs might explode.

Perceived exertion.    This method uses a numerical scale, typically from one to ten, that corresponds to how hard you feel yourself working – the rate you perceive that you are exerting yourself.

An activity rated 2 would be something that you could do forever, like sitting on the couch watching the rain fall.  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 6 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.

Measuring your heart rate.  This is a more precise way of monitoring your pace.  Your heart rate is called your pulse, and you can determine this number either by counting the beats at your wrist or neck or by wearing a heart rate monitor.

Your heart rate can tell you a lot about your body – how fit you are, how much you’ve improved, and whether you’ve recovered from yesterday’s workout.  But how do you know what heart rate to aim for?  There’s no magic number.  Rather, there’s a whole range of acceptable numbers, commonly called your target heart rate zone.  This range is the middle ground between slacking off and knocking yourself out.  Typically, your target zone is between 50 and 85 percent of your maximum heart rate, the maximum number of times your heart can beat in a minute.   

The most time-honored method for determining maximum heart rate is for men to subtract their age from 220 and for women to subtract their age from 226.  Keep in mind that this formula gives you only an estimate.  Your true max may be as many as 15 beats higher or lower.  Also, this formula is generally used for activities during which your feet hit the ground.

Using that easy formula to find your max, find your target heart rate zone by calculating 50 percent and 85 percent of your maximum.  Here’s the math for a 40-year-old man:

220 – 40 = 180 (this is his estimated maximum heart rate.)  180 X .50 = 90 (This is the low end of his target zone.  Below this number and he’s not working hard enough. 180 X .85 = 153 (This is the higher end of his target zone.  If his heart beats faster than 153 beats per minute, he should slow down.

Okay, so now you know how to figure out your target heart rate zone.  But how do you know if you’re in the zone?  In other words, how do you know how fast your heart is beating at any given moment?  You can check your heart rate in two ways: taking your pulse manually or using a heart rate monitor.

When you’re just starting to work out, you may not have a good sense of how hard to push yourself.  And you may be working out harder than you actually need to.  Actually, this happens to advanced exercisers and athletes all the time.  Left to their own devices, they try to out-do themselves every day.  The smart ones use a heart rate monitor to remind them to slow down.  However, for most of us the problem is getting into a higher gear.

Finally, why can’t we work above the higher end of our aerobic zone?  The point at which your extra oxygen supply runs out and you slip into the reserve mode is referred to as your anaerobic threshold.  When you’re in poor physical shape, your body isn’t very efficient at taking in oxygen, and you hit your anaerobic threshold while exercising at relatively low levels of exercise.  As you become more fit, you’re able to go farther and faster, yet still supply oxygen to your muscles.  By monitoring your heart rate, you can be careful not to become anaerobic (gasping for air, feeling that burning sensation in your legs) and forced to stop exercising.