Cardiorespiratory conditioning can be defined as the ability of the circulatory and respiratory systems of the body to supply oxygen to the tissues of the body. The cardiovascular and respiratory systems work in conjunction in order to supply oxygen-rich blood to the tissues. The advantage of improving cardiorespiratory fitness include; increasing the ability to perform day-to-day activities without fatiguing; improving energy levels; improving general health; lowering risk of acquiring chronic diseases and improving quality of life.
The role of the cardiovascular system:
1. To circulate blood throughout the body
2. To circulate deoxygenated blood from the rest of the body to the lungs
3. To circulate oxygenated blood from the lungs to the rest of the body
4. To increase the pressure of blood in circulation in order to increase the diffusion of oxygen from blood vessels into tissues
5. To increase the amount of blood circulated during increased demand
The role of the respiratory system:
1. To inhale oxygen and transfer it from the lungs into blood vessels
2. To transfer carbon dioxide from blood vessels into the lungs for exhalation
Cardiorespiratory training should be the basis of all conditioning due to its widespread benefits related to all components of fitness. It is advised that cardiorespiratory training be undertaken prior to any other training in order to develop the conditioning of the heart, lungs and general circulation, so that these systems are adequately equipped for the more intense demands of other forms of training. Some adaptations to cardiorespiratory training include:
1. Increased stroke volume due to left ventricular hypertrophy. This allows to heart to become more efficient during rest (lowering resting heart rate), as well as becoming more effective during periods of increased demand.
2. Increased capillarisation (growth of capillaries from blood vessels to and around tissues). This allows more blood to reach the tissues, increasing the amount of gaseous exchange that occurs between the tissue and the blood vessel.
3. Increased artery elasticity. This adaptation allows the blood vessel to dilate (increase in diameter) and constrict (decrease in diameter) more extensively. This allows the circulatory system to more effectively control the amount of blood as well as the pressure of the blood in the circulatory system.
4. Increased hemoglobin carrying capacity. This adaptation results in each hemoglobin molecule in the blood stream carrying more oxygen or carbon dioxide. This allows to tissue to increase its oxygen supply and therefore improve its performance and endurance levels. It also allows the tissue to more effectively clear carbon dioxide, thereby delaying fatigue for longer.
5. Increased lung volume. This allows the lungs to inhale and exhale more air, increasing the amount of oxygen absorption into the blood stream, and the amount of carbon dioxide exhaled.
6. Increased breathing efficiency. This delays fatigue, and is usually due to an increase in the strength and endurance of the muscles responsible for breathing.
These adaptations not only improve cardiorespiratory capacity, but also increase the capacity of other systems in the body, improve endurance levels, and delay fatigue during all exercise intensities.