The heart muscle is technically known as myocardium. The heart muscle sits in a fibrous sack called the pericardium. The heart muscle is fed through the coronary arteries and its beating is controlled through the Vagus nerve. The flow of blood through the heart is controlled by valves. The Aorta is the main vessel leaving the heart and the Vena Cava is the main vein entering the heart. The pulmonary vessels take blood from the heart to the linings and back again. The hearts inner surface is called the endocardium. The heart sits in a fibrous sack called the pericardium. This supports the heart in place prevents the heart overfilling with blood, reduces friction between the heart and the rest of the body and helps guard the heart against infection.
The “Heart rate” is the number of times per minute that the heart beats. The “stroke volume” is the volume of blood that is pumped with each beat. Blood pressure is the force that the blood is pressed against any obstructing object (or containing vessel walls). There are two measures for blood pressure – systolic the pressure when the heart muscle is contracting and diastolic when the heart muscle is relaxing
The heart is one organ that we are all fairly familiar with and we know its location and what it does or do we? In every culture in the world when we tell some one what our name is we point not at our brain but at our heart. Similarly when we gesture to accompany the words “I feel” we gesture to our heat. In English the language is full of words suggesting a deep importance to the heart. We are “heart broken”, we are “hearty”, and our emotions are “heartful or heartfelt”. In the west there is a growing belief, or should I say a re-belief, that the heart may have as much to do with emotion as it does with blood circulation.
The Physical Heart
The heart will beat 2.5 billion times during the average lifetime pumping enough blood each day (10,000 litres) to fill a petrol tank. When one considers that the heart is basically muscle tissue it is apparent that the “use it or lose it” philosophy applies as much to the heart as it does to any other muscle. The amount of heart muscle tissue will be proportional to the demands placed on the heart. Unused muscle tissue will over time be broken down. This means that if we lead a sedentary lifestyle muscle mass will diminish and if we suddenly place exertive demand on the heart then it may fail.
What we need then is exercise that loads the heart enough to stimulate the growth or maintenance of sufficient heart muscle to handle peak loadings without putting that heart muscle under serious stress. The use of muscles raises the oxygen requirements of those muscles which in turn requires that the blood be circulated in greater volumes - which is normally achieved through faster beating of the heart. With increased heart rate individual heart muscle cells are required to work harder and this increases the risk of failure. It seems as though, over time, the body then interprets this raised heart rate as a need to increase muscle mass and the heart will actually increase in size to generate a greater stroke volume with each beat so that the heart rate can remain at optimal levels. It is not only the muscle mass that increases here but also the connective tissue which provides the fibrous structure of the heart.
Research shows that a loading factor of 60% to 80% above normal blood circulation requirements is sufficient to keep enough “reserve capacity” in the system to handle peak loads (such as running up stairs) without significantly raising the chances of heart failure. This loading is exactly what is achieved when performing Tai Chi with bent knees at a rate of about 20 minutes per standard set (Yang’s 108 movements).
The heart rate is not only affected by actual blood circulation demands but by anticipated blood circulation demands. This is the role of the stress response. When the mind perceives danger then the body is geared up to deal with the sudden physical demands that such danger may result in. While this is a good evolutionary response in today’s modern world the stress response is often initiated by triggers that are continuous and do not require physical response. The heart beats too fast and the blood pressure is too high. Exercise which puts us into a “relaxed state” counteracts the “stress response” problems. There is a direct link between the breath rate and the “heart rate” so any exercise such as Tai Chi and Qigong which works directly to slow the breath rate will also work to slow the heart rate.
One might think that the objective of exercise is to raise the heart rate but one must also realise that if the heart rate rises sufficiently it becomes inefficient because the stroke volume drops. This happens because the heart muscle does not have time to fully relax before the next contraction commences this means not as much blood enters the heart ventricles. Overall the circulatory volume may go up, though in extreme circumstances this may actually fall, in either event the number of heart beats required to circulate a given volume of blood increases. This can be tolerated for short term physical loadings but overtime will damage the heart. Again exercise in a state of relaxation provides the solution. The volume of blood circulated still rises but more due to increases in efficiency and the contractile strength of the heart muscle.
The Energetic Heart
We are well aware that certain emotions place pressure on the physical functioning of the heart. Fear, Anger, Excessive Joy. Conversely there are other emotions which seem to benefit the heart, love, a state of happiness or joyfulness.
How do we exercise the “energetic heart”? In Tai Chi we try to use visualisations and to “feel” the Tai Chi this has a direct influence on the heart meridian. Physical movements also translate into energetic impacts and the nature of Tai Chi movement is particularly beneficial in terms of its energetic impact. The “Suspending the head top” technique is used specifically to “raise the Shen”. The prescribed use of the eyes in Tai Chi also helps to release the flow of Shen Qi.
The Heart and the Nervous System
The actual heart beat is generated by the sino atrial node, a structure that resides at the top left of the heart. The rate of beating is however the net result of the neural messages coming from the nervous system. The sympathetic system (the stress response system) speeds the heart beat – the more stimulated the sympathetic system becomes the faster our heart will beat. The Vagus nerve which originates in the brain acts as a break to the heart. The more relaxed our moods, the more comfortable the body, the more the sense of ease the greater the effect of the Vagus nerve. It is often referred to as the Vagal Brake. When one considers that nerve efficiency may be impacted as much as 40% by stress the effects of the Vagal brake can be significantly impaired by hypertension.
Blood may be a fluid but it can also be regarded as a complex organ in its own right. From a cardiovascular viewpoint we are interested primarily in blood viscosity. Blood pressure tends to be due primarily to the heart, blood vessels, and other structures outside the blood itself.
Blood viscosity or thickness is again a stress response. The body thickens the blood when in the stress response this means that less blood will be lost in the case of injury. The downside is that thick blood is harder to circulate than thinner blood. It makes the heart work harder. Exercise that promotes the relaxation response such as Tai Chi or Qigong are thus beneficial.
The stress response also stimulates the propensity of the blood to form clots – advantageous in the case of injury but hazardous for normal blood circulation with the potential to result in thrombosis and strokes. The combination of fast flowing blood in vigorous exercise combined with increased risk of tissue injury and increased clotting potential is a hazard. Exercise where the blood flow is stimulated but without any increases in clotting potential and little risk of physical trauma to the body would seem to be the optimal approach and this is exactly what Tai Chi and Qigong can achieve.
Arteries are distinguished from other blood vessels in that they contain a ring of muscle within the vessel that contracts to help push the blood through the arterial system. Stress can cause vasoconstriction of arteries. This is significant because as the diameter of a blood vessel decreases the level of resistance to blood flow increases this makes the heart work harder and forces up blood pressure and also risk arterial damage such as aneurysms.. Exercise in a relaxed state helps to reduce risk of arterial damage and the level of blood resistance. Also if arterial muscle cells like any other muscle cell are subject to prolonged contraction because of stress then stress would compromise the arterial blood pumping function.
Veins and the Venous Blood Return System
Veins are do not contain muscle cells of their own but veins are often threaded through muscles so that muscle contraction combined with a series of valves in the veins has the effect of pushing blood back towards the heart. When this system is effective the heart does not have to work as hard as when there is a loss of muscle tone. In fact muscular stress can actually be the cause of increased blood pressure as to circulate the blood through these areas of tenseness blood pressure must be higher than normal. If muscle tone is low then low blood pressure may be experienced as blood pools in the vessels and there is then inadequate blood pressure to maintain the brains blood supply and this can result in fainting and unconsciousness.
The PLANTAR PUMP is an important structure of blood vessels located in the sole of the foot. Relaxed and appropriate use of this pump is an important part of the legs venous blood return system. The nature of the footwork used in Tai Chi is particularly conducive to the activation of this pump.
The Lung Diaphragm Pump
Within the body torso there is little opportunity to use the muscles to assist the venous blood return system but here lie critical organs such as liver, kidneys spleen and pancreas to say nothing of the digestive and eliminative organs. When the Lung diaphragm is operating properly its downward movement increases the hydrostatic pressure in the abdomen. This forces the venous blood out of the organs and along the veins. Its upward movement causes negative pressure which causes the internal organs to expand drawing in fresh arterial blood.
The capillaries are the fine blood vessels that take the blood out past the individual cells. In stress this network is often closed off to reduce blood loss and you can often see whiteness or pallor of the skin as a result. Again exercise in a relaxed state ensures that the tissues of the body benefit from exercise rather than suffer from it.
WHAT ARE THE VARIOUS CARDIOVASCULAR PROBLEMS AND HOW CAN TAI CHI AND TAI CHI QIGONG ASSIST
There are a wide variety of cardiovascular problems ranging from congenital defects, to problems with coronary arteries, heart valves, arrhythmias of the heartbeat, blood pressure problems, angina, aneurysms, cardiomyopathies, congestive heart failure, thrombosis, varicose veins and so on.
Often Tai Chi and Tai Chi Qigong can do little about the cardiovascular condition itself. The contribution of Tai Chi and Qigong can however still be significant:
First, Tai Chi and Tai Chi Qigong increase the efficiency and effectiveness of the cardiovascular system without raising risk levels to the cardiovascular system - beyond that which would be encountered in normal daily activities. In other words Tai Chi helps get the best out of the cardiovascular system that does exist.
Second, Tai Chi and Qigong help to counter the secondary effects of cardiovascular problems such as stress, sedentary lifestyle, depression, anxiety and so on. Since many of these factors impact negatively on the Cardiovascular system Tai Chi and Tai Chi Qigong can help break a downward spiral of cause and effect and even reverse this in certain cardiovascular issues such as blood pressure.
One thing that often causes confusion is how Tai Chi can be both beneficial to high and low blood pressure. The relaxation response developed in Tai Chi helps to reduce blood viscosity, take stress out of muscles and encourage vasodilation. What is happening here is the reversal of stress response effects. Once the stress response effects have been reversed there are no further effects on lowering blood pressure in other words the relaxation response can only normalize blood pressure – providing that there are no inherent low blood pressure problems.
In low blood pressure situations - poor muscle tone and a degraded venous blood return system are often the problem. Tai Chi and Tai Chi Qigong improve muscle tone; increase the use of the lung diaphragm and plantar pump and the rhythmic movements of muscles will all assist in raising blood pressure to normal levels. Again none of these effects can of themselves cause high blood pressure. Tai Chi and Tai Chi Qigong should therefore be seen as exercise techniques that act to normalize blood pressure.
CHIEF INDICATORS OF CARDIOVASCULAR PROBLEMS ARE:
· Unhappiness, depression and hostility.
· Poor Nutrition
· Sedentary lifestyle
· Smoking and excessive Alcohol intake
· Genetic predisposition
SECONDARY COMPLICATIONS OF CARDIOVASCULAR PROBLEMS ARE:
Often relating to reduced mobility) include:
· Muscle wasting.
· Loss of bone density from decreased activity.
· Lowered immune response
· Reactive depression.
· Increased falls risk.
· Lowered vitality.
· Increased risk of obesity.
· Sleep disturbance.
· Increased stress levels
As you can see many of the secondary effects of cardiovascular problems are also indicators for cardio vascular problems indicating a negative feedback effect.
WHY ARE PEOPLE WITH CARDIOVASCULAR PROBLEMS REFERRED TO TAI CHI CLASSES?
Medical practitioners are aware that exercise and relaxation techniques are beneficial to those with cardiovascular problems and refer patients for exercise for the following health objectives:
Increase level of physical activity
Reduce degree of hypertension
Maintain general fitness
The general reason that students with Cardiovascular problems get referred to Tai Chi rather than other exercise classes is that Tai Chi is perceived as a soft gentle exercise that will achieve the above health objectives without exposing the student to significant risk of cardiovascular overload.