Age Associated Changes to the Cardiorespiratory System
The Cardiorespiratory system includes the heart and lungs. Together they provide the body with Oxygen and remove Carbon Dioxide, the primary waste product of metabolism. They are broken down into two categories, namely, Cardiovascular (Heart) and Respiratory (Lungs).
This is responsible for the transportation of oxygen and other life sustaining nutrients throughout the body. There are very few age related structural changes within the cardiovascular system.
There is a normal enlargement of the heart primarily due to an increase in cardiac muscle cells. Additionally fat tissue in the sinoatrial node increases and pacemaker cells decrease leading to a normal slowing of electrical activity of the heart. This slowing of the electrical activity may lead to an abnormal slowing of the heart which at times may require the implantation of an artificial pacemaker to adequately pace the heart.
In addition to changes in the heart, there are notable changes to artieries, arterioles and capillaries. Artierioles may thicken and widen becoming stiff with age forcing the heart to work harder to push blood around the body. This often leads to age associated hypertension (high blood pressure). Arterioles experience a reduction in the ability to dilate and widen, constrict and narrow which also often affects exercise tolerance. Furthermore, capillaries narrow with age resulting in a reduction of blood flow.
In terms of functional changes to the cardiovascular system, there is a decrease in the overall efficiency which results in a reduced responsiveness to exercise.
This works in conjunction with the cardiovascular system to provide oxygen and remove carbon dioxide by playing a significant role in air exchange in and out of the body.
Ageing results in the loss of elasticity of lung tissue that leads to a reduction in the time airways are open.
The diaphragm and intercostal muscles weaken with age resulting in stiffness to the chest wall which the diminishes the lungs ability to expand and contract.
These structural changes have little effect of functioning at rest but may affect exercise capacity and ability to participate in activities that place a significant demand on cardiorespiratory system.
Below are some potential fitness considerations as a result of the effects of ageing:-
Lower maximal heart rate
Lower training heart rate
Slower recovery rate
Decreased tolerance to fatigue
Lower anaerobic threshold
Less tolerant of high-intensity exercise
Taking all of the above into account it appears that there is no benefit known of physical activity to the respiratory system alone. However, it does appear that physical activity preserves cardiorespiratory fitness and significantly reduces the risk of coronary heart disease.
Furthermore, for those adults that are active in later life, resting heart rates decrease resulting in an increase in stroke volume at rest as well as an increased cardiac output and stroke volume.
All in all, inactivity is one of the major risk factors for coronary heart disease and therefore it is highly recommended to remain as active as possible in later life.