Repeated stress will cause extra work for the heart, the blood vessels and the kidneys. In simple terms, this will cause wear and tear of the system. Thus, repeated activation would cause fatigue and damage the heart and other major systems. Logically, we should then experience heart problems after many years and very late in life. We are all familiar with anecdotes about the incidence of heart diseases in younger people. In India, the incidences of cardiovascular diseases have gone up dramatically during the last two decades and this rise has been blamed on the modern lifestyle and stress.
Unfortunately, we see that the cardiovascular diseases are showing up in even young and middle-aged people. How does repeated stress actually cause heart disease even in young people? In this section, we will take a closer look at the system to understand the source of the problem.
In order to appreciate the way stress response causes cardiovascular problems, we need to understand a little more about the blood vessels and how they can be damaged. A general feature of our circulatory system is that larger branches bifurcate into smaller branches and so on till we reach the tiny capillaries.
This bifurcation is an extremely efficient way to organize the circulatory system and the net result is that no cell in the body is more than five cells away from a blood vessel. If you think about the number of cells in the human body1 (approximately 100 trillion) you will realize that this is no small accomplishment. Now for the really amazing part—the circulatory system represents less dian 3 per cent of the total body mass!
The efficient circulatory system, however, has one major drawback. The points of bifurcation suffer from high forces as blood slams into it. These branch points are thus particularly vulnerable to injury. As we can imagine, if we increase the blood pressure, there will be greater turbulence to the flow and the branch points will experience even higher forces and will wear and tear and cause scarring of the arteries.
Recall from chapter 4 on metabolism, what the body does in the face of a stressor. It takes out money from the bank to pay for the defenses of the body—it releases triglycerides and glucose in the bloodstream. Now these globs of fat and glucose will stick to scarred and worn artery joints. In response to stress, the sympathetic nervous system increases the viscosity of blood by causing the blood platelets to clump. These clumps also stick to the arteries and add to the problem.
Exacerbating the problems, cells full of fatty nutrients called foam cells begin to form there too. The arteries then clog and blood flow through them decreases. In scientific jargon it causes atherosclerosis. An accurate description of this phenomenon is the accumulation of plaque made of fats, starches, foam cells and calcium underneath the inner lining is a process of cellular reproduction, so as you grow bigger you are made up of more cells. Following a similar logic, a larger person is larger because they have more cells, not because their cells are larger. In fact, cell types have a fairly uniform size across the entire human species.
Now look at the ending of this drama—form enough plaque and restrict the blood flowing to the lower parts of the body. Your legs and chest will hurt like crazy whenever you walk due to lack of oxygen and glucose. You are a candidate for bypass surgery. If the same problem occurs for arteries going to the heart, you end up with coronary heart disease, and other horrible things. If you are really adventurous and have plaque in the arteries going to the brain you get a stroke—a brain thrombosis.
Now, for some more bad news. We have seen earlier how chronic stress messes your arteries and can lead to major problems in a short time. In times of stress, we have seen that the sympathetic nervous system increases the heart rate. The heart muscles require additional energy for performing this extra work and the body conveniently dilates the arteries supplying the heart muscles to divert more oxygen and glucose. The bad news is that in people with damaged arteries (specifically, plaque in the arteries going to the heart), the arteries instead of dilating now constrict!
This is very different from the vasoconstriction where some of the major arteries are constricted to increase blood pressure. Here we are talking of the small arteries that supply essentials to the heart that constrict instead of dilating. As a result, the heart is deprived of energy and oxygen just when it needs them the most (the scientific term for muscles being deprived of oxygen and nutrients is called ischemia). Your chest hurts like hell—scientific name for this condition is angina pectoris. Depressingly, it turns out that it takes only small periods of high blood pressure to cause the problem, of contracting arteries.
The advent of modern imaging devices has allowed physicians to observe the working of the circulatory system at subtle levels. The surprising finding was that there were a number of episodes of heart artery contraction occurring all the time. Most of these episodes are painless (called silent episodes as they do not give out a warning signal of pain). Earlier, cardiologists warned you to be careful while undertaking physical activity if you had atherosclerosis.
It appears that for such people trouble occurs all the time under normal psychological stress. It seems that the damaged system becomes very sensitive to stress whether physical or psychological. Each succeeding stressor makes the system more vulnerable till it all comes to a head with some cardiac catastrophe—the story of the person sitting or sleeping and being struck down by a sudden heart attack. It is incorrect to call it a ‘sudden heart attack’.
The drama has been playing out for a long time in the body as we have seen earlier. One of the most striking though unsurprising features of heart disease is that many times the catastrophe strikes during periods of extreme stress. Typical scenarios involve death of someone close, in the face of close personal danger, threat of a serious injury, and loss of status or self-esteem. The general consensus among cardiolo-gists is that a sudden cardiac episode is an extreme version of acute stress causing heart ischemia coupled with ventricular fibrillation2 or arrhythmia.3
Another story we have all heard is of people getting a heart attack after hearing of some major triumph or very happy news (winning an election, winning the lottery). This seems crazy. All the preceding discussion featured stress as the culprit and happiness does not fit into this category. If you pause to think for a moment, the idea does not seem farfetched at all. Extreme joy and extreme fear obviously have different effects on the various parts of the body but for the cardiovascular system the effects are roughly the same.
Pounding your chest and wailing loudly or jumping up and down with joy pi ace similar demands on the heart and can cause problems for the diseased heart. Think back to the definition of stress as any event that causes the body to be thrown out of allostatic balance. It does not matter in which direction the disruption takes place; it is the quantum of disruption that matters. Clearly, extreme joy causes the disruption to the allostatic equilibrium for the cardiovascular system just as extreme stress does.