Cardio - Are you working hard enough?

You can probably picture the cardiovascular equipment room within a fitness center: a few rosy-faced individuals pounding out sprints on the treadmill, two friends chatting next to each other on the Ellipticals, someone reading People magazine on the bike, another reading a novel on the Stairmaster with elbows locked out and leaning on the handlebars...you get the picture. All of them will say, "I went to the gym and did 30 minutes of cardio." But who was actually working hard enough?

When it comes to cardiovascular exercise, "working hard enough" refers to the body's ability to accomplish two things: caloric expenditure and improvement in the capacity of the cardiovascular system (i.e. the heart and blood vessels' ability to deliver oxygen to the skeletal muscles).

Caloric expenditure will happen at any intensity level. You burn calories even when you're at rest. However, and this is sort of a no-brainer, the more intensely you exercise, the more calories you will burn. For example, let's say you're a 150-lb person and your goal is to burn about 500 calories. You just put it in an hour on the treadmill...did you work hard enough? If you walked the hour, the answer is no. You probably expended about 300 calories. If you jogged, the answer is yes as you probably burned closer to 500 or 600 calories. Clearly, higher intensities offer greater caloric expenditure and overall duration can be reduced to meet a specific goal.

Unlike reaching a desired caloric expenditure, which can be achieved through a balance of intensity and duration, improving the ability of the cardiovascular system must be achieved through reaching a desired intensity, or heart rate. To improve cardiovascular fitness, you need to exercise within your target heart rate range which is approximately 64%-94% of your maximum heart rate (MHR). MHR is estimated as 220 - age.

It's not as confusing as it sounds. I'm 25 so my MHR is 220 - 25 = 195 beats per minute. I should be exercising within a range of 125 (195 x .64) and 183 (195 x .94) beats per minute.

As a quick test to calculate heart rate while at rest or while exercising, count your pulse for 6 seconds and add a "0" to the number. For example, if you counted "7," your heart rate is about 70. To achieve my target heart rate of 125-183, I would hope to be counting between 13 and 18 beats in 6 seconds which would estimate my heart rate at 130-180.

An even quicker way to estimate if you are in your target heart rate range is to use the Talk Test. If you can carry on a conversation while exercising just as you would if you were sitting around the dinner table, your intensity is too low. However, if you are so out of breath doing your cardio that you are unable to speak, your intensity is too high. You should be slightly winded but able to talk to someone while exercising.

Whether you monitor calories on the treadmill display, estimate your target heart rate using a 6-second pulse, or use the talk test, the main idea is to check in with your body and periodically ask yourself the question, "Am I working hard enough?" The more you focus on Britney's latest pregnancy, the less you are able to focus on your own body.