Aerobic fitness

I can still remember the first time that I went running. Imagine a 120kg person, who has been a smoker for 7 years and in his 21 years the biggest part of his physical activity was moving from the bed to the couch and on rare occasions to go to the bathroom. Well, needless to say I managed to run for about 5 minutes and during the time I felt like I was going to cough up a lunge and that my heart was going to jump out of my chest. And the next few days, my legs were so sore I could hardly stand, yet alone walk. Thankfully my body has adapted to running and I’m now able to do a 15km run for 6 days per week.

Last week I told you all about how our bodies adapt to cardiorespiratory exercises. Let’s not forget, that any physical activity is considered as stress, as far as our bodies are concerned.

Let me recap what I already told you:

The benefits that enhancing your cardiovascular fitness level will bring:

-          It lowers your heart rate and it lowers your blood pressure,

-          In increases the size of your heart and improves your cardiac output,

-          It increases the number of capillaries in muscles and tissues like lunges,

-          It increases energy production in muscle cells,

-          It gives you more energy in your daily life.

Now, there are a few things that I want to add to this list.

Our bodies have two major energy systems. One is called aerobic (with oxygen) and the other anaerobic (without oxygen), the first one produces and uses adenosine triphosphate (ATP) and the other one uses it. ATP is an energy dense molecule and is an energy source for our body, just like gasoline is an energy source for cars. The dividing line between both systems is a really thorny issue with fitness experts. Some claim, that you only need to work up to 50% of your maximum effort, before you switch from aerobic to the anaerobic cycle, while others claim, that the bar can be raised as high as 85%. But it is generally believed, that an untrained individual has an anaerobic threshold of 55% and a trained one at 85-90%.

Maximum effort is nothing more than max heart rate, and can easily be calculated with the following formula; MAX HR = 220 – AGE. Of course, this is not the only way to determine your max heart rate. This site has a calculator, where you can do the math yourself, if interested. 

Advising people, where their heart rate should be is a tricky thing, because you need to keep in mind the clients goals, their physical fitness, age and sex. The max heart rate for an occasional male jogger and that of a female bodybuilder are completely different and need to be adjusted to their needs.

So, while you are training in the aerobic zone, most of the energy comes from blood and muscle glucose and after that from the fatty acids stored in the adipose tissue (fat cells) that are metabolized in the presence of oxygen. The body produces water and carbon dioxide, both very easy for the body to get rid of. This type of metabolism is active while you are walking, jogging, running, swimming, cycling or doing some other form of a low intensity exercise. Sure, after training you will be a bit sore and tired, but if you continue with your training on a regular basis, your body will adapt to it, and the pain will be gone. Aerobic training does not leave the muscle tired and sore and it will increase the capacity of the aerobic system.

Don’t forget, this metabolic pathway is only active, when there is enough oxygen!

And what are the other great advantages you get with doing aerobic exercises?

It reduces body fat, helps you to control weight, decreases total cholesterol and increases HDL (good) cholesterol, increases maximal oxygen consumption (VO2 max), Increased threshold for muscle fatigue and it makes you feel good with all of the chemicals that are releasing in your brain.

So, this was just a brief explanation on how the aerobic system works. Next time I’ll give you tips on how to start if you’re just a beginner or how to improve your anaerobic fitness level, if you already are a trained individual.

Until next time, keep strong and be kind.

Picture taken from: http://tiny.cc/qrvmhw