Cardiovascular Training

Cardiovascular Training Part 2 by Julie Enstall

Welcome back to our Cardio discussion.

In the last article, we covered some very broad ranges of your cardiovascular system. We measured them by percentage (%) of your Maximum Heart Rate (MHR) and Rating of Perceived Exertion (RPE). Now I want to answer some frequently asked questions: What is the benefit of a low resting heart rate? How hard should I exercise? What is my “Fat-Burning Zone?” What is Heart Rate Training and why is it important?

Let’s start with the last one. Heart Rate Training is simply monitoring your heart rate to achieve the results you want from your exercise program. With a heart rate monitor, you can determine at what percentage of your MHR you are at all times. The following will help you understand each of the Heart Rate Zones.

0% - Death

25%-50% - Recovery Zone – This is where your heart rate is during rest. The resting heart rate of very fit people is approximately 40-50 beats per minute or about 25% of their maximum. The resting heart rate of unfit people is often 75-90 beats per minute or about 45-50% of their maximum. So why is it better to have a lower resting heart rate?

Fit people have a wide recuperation zone, which allows them to handle emotional and physical stress better. For example when a fit person gets a cold or the flu, their heart rate may increase up to 35% of maximum, but they are still well within their recuperation zone. On the other hand, when an unfit person gets sick, their heart rate can easily get pushed out of the recuperation zone, making it harder for the body to repair itself. Being unfit can cause a person to take longer to recover from illness, as well as requiring them to need more sleep or complete bed rest to allow their bodies to heal.

A fit person might still get a cold or flu, but the body can repair itself more quickly and while maintain a higher level of activity than the unfit person. What might be complete bed rest for the unfit would be a slower pace for the fit person.

The same is true for stress. The body requires rest to repair itself and build the necessary tissue and enzymes for normal body function. If stress elevates the heart out of the recovery zone, the body cannot perform these functions effectively, causing a breakdown in any of the numerous systems the body maintains.

Don’t underestimate how important it is increase your fitness level by lowering your resting heart rate. It can affect your quality of life across the board.

50%-60% - Sub-Aerobic Zone – While this zone will not reap many benefits in the way of fat-loss, it will produce some systemic benefits in very unfit people if it’s done enough.

65%-85% - Aerobic Zone – I am often asked where in this zone a person should work. Should I be more on the easy side or more on the hard side of my aerobic zone? My answer is: It depends on whether you fall into any of the following categories:

• Older People – Folks that are 70+ years old will benefit from the lower intensity work. It’s not that their hearts can’t take the exertion, but rather that as we age our bodies don’t repair themselves as quickly as they did when we were 20. It is as if our bodies are asking us, “Do you want me to build enzymes to replace skin cells, hair, and provide your normal bodily functions, or just repair the muscle tissue?” As we age, we do not synthesize proteins as well or as quickly. Working between 65%-75% will allow all of the cardiovascular benefits while still allowing the body to perform its other functions efficiently.
• Sick People – Just as with older folks, if we are sick, we are asking our body to fight infection and build muscle too. It is better to work in the lower ranges when recovering from illness.
• People who are restricting calories – If you are one of those people who restrict their calorie intake below 1000 calories (not recommended by this trainer), you are asking your body to do a lot of work with out much fuel. If you are trying to exercise at a higher intensity level and not eat much, your body is likely saying, “What do you want from me? I am repairing tissue, building muscle, re-synthesizing glycogen eat something!!”
• People who are stressed – I hear a lot of people say, “I am so stressed. I’m going to get in a hard workout.” While exercise will help reduce stress, working at really high intensities does not have the same benefits as it does for those with less stress. Research has shown that people who are stressed don’t synthesize protein very well, which means that they don’t repair or build tissue very well. Regardless of how good your diet, a stressed out person will benefit more from exercising at the lower end of the aerobic zone rather than the higher.

I have found that my clients who are having trouble achieving their fat loss goals struggle in one of two areas. Either they are working at such a low intensity level that the calories they are burning are way below what they are consuming or they are burning at such a high intensity that they are training their bodies to use and crave only sugar. Let me explain how your body burns fat and sugar (glycogen) as fuel.

Let’s use an example of a 130-pound woman walking at 60-65% of her maximum heart rate (MHR). In 30 minutes she will burn approximately 146 calories, about 50% of the calories burned are fat (73 fat calories).

Now if the same women were to jog for 30 minutes getting her heart rate to 80-85% of MHR, she would burn approximately 206 calories, 39.85% would be from fat (82 fat calories).

Even though the percentage of fat decreased her total fat calories increased.

As her body recovers, she will replenish what her body used in the form of blood sugar. Therefore her post exercise period can also help her burn body fat.

Of the approximately 160,000 calories stored in the body, only about 2,500 come from sugar, about 23,000 are protein, and 134,500 are from fat.

85% - Anaerobic Zone – In this zone the primary fuel source is sugar. Since we do not store many of our calories as sugar, we cannot stay in this zone very long, but that is not to say we should never use this zone. The most effective way to increase your fitness level and burn fat calories is to do intervals. Working in this zone for short bursts can help your body increase the number of fat burning enzymes as well as burn more total fat calories.

I hope you have enjoyed our discussion of this very important system of the body. If you would like a more information or a customized program designed for your specific needs, please feel free to call me at 314.743.4453 or email me at julie@bodylogicfitness.com.