I hope you are enjoying reading this blog series as much as I am enjoying writing it! So far I have covered quite a few topics, with the idea being to educate you on all of the components the contribute to health, fitness, and performance. This will be the last topic specific post before putting all of the pieces together and discussing overall exercise program design.
The topic of this blog post is cardiovascular training, or cardio for short. All though all of the systems throughout the body are utilized during cardio training, the two that are targeted specifically for adaptation are the cardiovascular (heart and blood vessels) and the respiratory system (lungs). The role of the cardiovascular system is to supply nutrients and oxygen to the tissues of the body, then remove carbon dioxide and waste products. The respiratory system’s role is to supply oxygen and expel carbon dioxide. If you remember the secret I revealed in Part 6 of this blog, it is that the purpose of all training is to create adaptation in the body’s system to improve their function. The adaptations that take place from regular cardio training include:
1) The muscular walls of the heart thicken to allow for more powerful contractions.
2) The left ventricle increases in size, increasing stroke volume when the heartbeats.
3) Cardiac output increases due to 1 and 2, meaning more blood can be pumped with each heartbeat.
4) VO2 Max increases, which is the maximum amount of oxygen your body can utilize.
These adaptations lead to a decrease in resting heart rate and a decrease in blood pressure, especially in individuals that are hypertensive. Simply put, the heart and lungs don’t have to work as hard to perform tasks because of improved efficiency. Think of it like fuel efficiency for your car. You’re getting better gas mileage!
Before I talk about cardio training methods, I want to briefly explain the energy systems that produce muscle contraction. All muscle activity is made possible by the production of and utilization of Adenosine Triphosphate (ATP). There are three energy systems that supply ATP: the phosphagen, glycolytic, and oxidative system. All are utilized during exercise, but which system is predominately supplying ATP depends on the activity. For the sake of simple explanation, think of phosphagen as sprinting, glycolysis as running, and oxidative as brisk walking. The reason this is important is because there is a major misconception that oxidative training (steady state cardio) is the best way to improve body composition. This is incorrect because it is time prohibitive. Besides, a higher caloric burn can be achieved with other methods of cardio training (interval, repetition, and pace cardio) in a shorter period of time. After intense bouts of exercise, the oxidative energy system aids in recovery for up to 4 hours. This is called excess post-exercise oxygen consumption (EPOC). You get more bang for your buck this way. Slow long duration training has its place and should be used regularly, but it shouldn’t be the only method used to improve cardiovascular fitness.
I’m off my soapbox now and will describe interval, repetition, pace, and steady state training below:
Interval: 1:1 work to recovery ratio. Work bouts should be near maximal capacity and should be 3-5 minutes in duration. Training session should last between 20-40 minutes.
Repetition: 1:5 work to recovery ratio. Work bouts should be maximal and last 30 seconds – 1:30 minutes. Training session should last between 20-40 minutes.
Pace: Near maximal pace (speed or intensity) maintained for 20-30 minutes.
Steady State: Constant submaximal pace (speed or intensity) maintained over 30 – 120 minutes.
In the last installment of this blog series, I’m putting it all together! You’ve learned all of the components, now I will give you some general guidelines on how to exercise so that you can achieve your goals.