Heart disease is the most common cause of death in the US – yet in many cases, it could be prevented. Our guide shows how you can take better care of this most vital organ.
How does your heart work?
The heart is a hard-wearing muscular pump that drives blood through the body.
With reasonable care, it can keep pumping for 70, 80 or even 90 or more years. It lies in the middle of the chest between the lungs and is protected by a bony cage consisting of the breast-bone, ribs and spine. It is about the size of the owner’s clenched fist and rather larger in athletes.
The heart is really a twin pump with four muscular chambers – two on the left and two on the right, with a muscular wall separating each side. The right side receives used blood from the body and pumps it to the lungs, where it takes up oxygen and loses carbon dioxide. The oxygen-rich blood then returns to the left side of the heart and is pumped to the tissues of the body.
The heart muscle receives oxygen from its own special coronary arteries – not from the blood inside its pumping chambers. A normal heart beats 60 – 80 times a minute (faster in children) and pumps about half a cup (70ml) of blood with each beat.
When a healthy man exercises, his heartbeats may increase to 180 per minute, during which time 25 liters of blood may be pumped. An average adult’s heart beats more than 100,000 times each day. During a normal lifetime, it pumps about 200 million liters of blood!
Overall heartbeat control is from the brain, but the trigger is a small bundle of muscle fibers and nerves – known as a pacemaker. It operates as a self-activating “spark plug” sending out very small electrical impulses to initiate contraction in different parts of the heart muscle. The rhythmic impulses are then transmitted through special conducting tissue to coordinate the heart’s contractions.
Heart block occurs when the electric impulses are interrupted or blocked somewhere along their pathway. An artificial pacemaker is a small, electronic device that emits electric impulses. Implanted in the body it acts as a substitute for a defective natural pacemaker.
Heart disease is the general term used for:
- Coronary Heart Disease (CHD), which accounts for 85 percent of all heart deaths.
- All other heart diseases including structural defects and rheumatic heart disease from bacterial infection.
CHD is caused by the clogging and narrowing of the coronary arteries – the special blood vessels that nourish the heart muscle. It is due to an artery disease called atherosclerosis (hardening of the arteries).
A heart attack or “coronary” occurs if a coronary artery becomes completely blocked and prevents the blood from nourishing part of the heart muscle. It is not due to disease of the muscle itself, nor is it the inevitable result of aging.
Atherosclerosis also occurs in arteries elsewhere in the body and may affect the brain, kidneys, legs, etc. In total, artery disease accounts for more than 50 percent of all deaths in the US.
Because so much is known about it, CHD is reasonably predictable. For example, high blood pressure, tobacco smoking, raised blood fat levels, and lack of physical activity are all associated with a higher chance of CHD and are known as risk factors. Some can be eliminated and others modified so that our overall risk of CHD is reduced to the lowest possible level.
Atherosclerosis (hardening of the arteries) is a degeneration of the part of the inner lining of the artery wall, characterized by deposits of fatty substances that bulge into the artery channel forming a bottleneck. As a result, the heart muscle may not obtain as much oxygen-rich blood as it needs.
The disease probably develops as a repair patch to a minute injury of the lining of an artery wall. Some people may be more susceptible to various factors that may trigger the injury. These include high blood pressure, high blood cholesterol levels, and tobacco toxins.
While the effects may not be obvious until the onset of a heart attack in middle age or later, the atherosclerotic process can start in childhood and progress into adulthood. Even babies as young as 3 months have been affected. Adolescence is believed to be a critical period in which the disease may become firmly established. Hence the importance of a preventive lifestyle from an early age.
Atherosclerosis develops in three stages.
- The first is the development of fatty streaks. Damage to the inner wall of the artery allows the infiltration of fatty substances. At this stage artery damage is minimal. It may proceed no further and may be reversible. Blood flow is not seriously affected.
- The second stage is the formation of soft plaque. Repeated injury at the fatty streak site stimulates a thickening of the artery’s middle layer. Deposits of cholesterol, fatty substances, connective tissue, and blood products form a soft cap or plaque. This bulges into the artery channel, restricting the blood flow.
- The third stage is the formation of hard plaque when all three stages of the artery are affected as calcium infiltrates the now ulcerating area to form a gritty mass of dead tissue. The artery channel is now almost blocked. A blood clot could form to seal off the artery.
While atherosclerosis in the coronary arteries is especially hazardous, the disease may also affect other arteries, particularly at those sites where they divide or bend.
How do I know if my chest pain is serious?
Atherosclerosis of the coronary arteries may develop slowly to the point where complications arise without any warning. Chest pains are often an announcement of those complications, which include:
1. Angina pectoris
This is chest pain or discomfort which may radiate to the neck and jaw, or down either arm to the elbow. It signifies that the heart muscle is not receiving sufficient oxygen-rich blood for its immediate needs.
Angina usually occurs during physical exertion, emotional arousal, or even after a heavy meal. At these times when the heart works harder and requires more oxygen than can be delivered through the narrowed arteries, pain is the heart’s demand to slow down. Relief comes with rest and is sometimes aided by anti-angina tablets.
An angina attack is not a heart attack. The heart muscle recovers from the temporary oxygen shortage before damage occurs.
2. Heart attack (myocardial infarction)
Chest pains or discomfort similar to angina, but lasting more than 10 minutes, could signify a heart attack. This means that a portion of the heart muscle (myocardium) actually dies (infarcts) due to a sudden and prolonged oxygen shortage.
A heart attack may be due to insufficient blood flow through a diseased and narrowed coronary artery. The formation of a blood clot on the diseased lining of the coronary artery is another cause of heart attack related to atherosclerosis.
A heart attack is not always fatal. The severity depends on the amount of heart muscle that is damaged and on whether any complications arise.
3. Heartbeat disturbances (arrhythmia)
Whenever the heart muscle is impaired by an oxygen shortage, its “electrical system” may be upset. When this happens, extra heartbeats and non-rhythmic muscle contractions interfere with the pumping efficiency. Heartbeat disturbances can sometimes result in sudden death.
Blood clots form naturally to halt bleeding from injured blood vessels. However, sometimes an unwanted blood clot forms inside a blood vessel, with the possibility of blocking it completely.
Thrombosis is the blockage of a blood vessel by a blood clot (thrombus) and is most likely to occur in the presence of atherosclerosis, but it may also occur where blood flow is sluggish. If thrombosis occurs in an artery leading to the brain it may cause a stroke.
When thrombosis occurs in a coronary artery, oxygen-rich blood to part of the heart muscle may be cut off. If the affected part dies, this is a heart attack due to a coronary thrombosis. It is also known as coronary occlusion.
The severity may depend on whether a large or small artery is blocked. The larger the artery, the greater the damage. If more than 30 percent of the heart muscle is damaged, death may result. On the other hand, damage to less than 5 percent may go unnoticed.
A stroke affects the brain, not the heart, but it is included here because it stems from the same underlying factors as heart disease. Next to heart disease and cancer, stroke is the most common cause of death in the US.
A stroke occurs when the blood supply to a part of the brain is either cut off or reduced to an insufficient trickle. Part of the brain tissue is then starved of oxygen and inactivated. The muscles, nerves, or organs controlled by the affected section are then paralyzed. It is as though a switch has been turned off suddenly. Paralysis, loss of speech, blindness, or a vacant mind may result.
High blood pressure is a major risk factor for a stroke, and the incidence is increased among those who smoke and women who take contraceptive pills – especially if they smoke as well.
Strokes usually occur in later years, but young people can be affected.
Seek medical advice if you have any of these signs:
- sudden, temporary weakness or numbness in an arm or leg;
- temporary loss or thickness of speech;
- a sudden blackout of one eye or temporary dimness of sight;
- paralysis or numbness of one side of the face;
- unexplained headaches or a change in headache patterns;
- temporary dizziness or fainting.
Although there are some unanswered questions about CHD, generally the earlier a healthy lifestyle is adopted, the greater the long-term benefits. For this reason, children should be taught to be critical of, and avoid, the various unhealthy influences.
Most of us have been conditioned to rely on medical science to cure us when we are ill. This is fine for some ailments or diseases – but there is no foreseeable cure for CHD. The answer lies not in “repairing the results” but in “stopping the cause”. To the extent that CHD is largely preventable, it remains a disease of choice – your choice!
1. High blood pressure
This is a major risk factor. People with high blood pressure have up to 4 times the risk of heart disease. Even moderately raised blood pressure leads to higher risk. About 1 in 6 Americans has high blood pressure, often without knowing it as there are no early warning symptoms.
Blood pressure is the force exerted by the bloodstream against the artery walls. It drives blood to all our tissues. Blood pressure increases and decreases in waves. The pressure is highest during the heart’s contraction (systole) and lowest between beats (diastole) when the heart is relaxed.
High blood pressure (medically called hypertension) means that the pressure of blood inside the arteries is higher than it should be.
Hypertension is not the same as nervous tension, though stress may contribute to it or aggravate it. Hypertension, once detected, can be readily controlled in the early stages. Hence the importance of having your blood pressure checked.
The cause of about 95 percent of hypertension is unknown, but it is probably influenced by a combination of heredity and lifestyle factors. The other 5 percent is due to medical conditions that can be cured, or to the effect of various drugs and medications.
Heredity appears to be important mainly in the presence of various lifestyle factors, including excessive use of salt, obesity, smoking, stress, inactivity, excessive use of alcohol, and using the contraceptive pill.
Tips for controlling blood pressure:
- Watch your weight. Blood pressure rises with increases in body weight and falls when that weight decreases.
- Eat less salt and salty foods. An appreciable lowering of blood pressure is possible in some people by salt reduction alone.
- Take adequate exercise. Planned physical activity helps some people to reduce blood pressure. Before any vigorous exercise, have a medical check.
- Learn to manage stress. Psychological stress plays a role in the initiation and/or aggravation of hypertension. More relaxation is useful to relieve stress. Modify compulsive, hurried, or competitive behavior patterns.
- Avoid tobacco. Nicotine raises blood pressure.
- Reduce high alcohol intake. Alcohol raises blood pressure.
- Avoid drugs and medicines that raise blood pressure.
2. Cigarette Smoking
This is a major risk factor. The risk of heart attack is doubled in heavy cigarette smokers. The risk of sudden death from heart attack is 5 times higher than for non-smokers but the risk for ex-smokers decreases to almost the same level as that of those who have never smoked.
Nicotine is a poison that was once used as a potent insecticide, but which is now prohibited because of its high toxicity to humans. Ironically, cigarettes may contain unlimited amounts of it, and are freely available! Because only small amounts of nicotine are absorbed with each puff, the effects of smoking are non-fatal, but still harmful to the heart and circulation.
Nicotine increases blood pressure and heart rate. It may also promote atherosclerosis (hardening of the arteries) and thrombosis in blood vessels. It may upset normal heart rhythm.
The same toxic gas that occurs in car exhaust fumes also occurs in cigarette smoke. The more you smoke the greater the amount of carbon dioxide absorbed into your bloodstream.
Women who use birth control pills are more prone than others to circulatory and heart problems. Women who smoke as well, therefore, place themselves at even greater risk.
Cigarette smoke is also potentially harmful to non-smokers, particularly in confined spaces. People who already have heart disease are most susceptible and should avoid smoky environments.
There are two types of smoke from cigarettes: mainstream and side stream. Mainstream smoke is that inhaled and exhaled by the smoker. The lungs absorb some smoke components, but significant amounts are exhaled.
Mainstream is less toxic than sidestream smoke which drifts from burning cigarettes. It is concentrated and unfiltered – and more hazardous. It contains 5 times more carbon monoxide, 4 times more tar and nicotine, and 40 times more carcinogens than mainstream smoke.
3. Stress and Behavior Patterns
Many heart attack victims are always rushed, over-ambitious, and easily agitated. This “full speed ahead” behavior may be an important factor in heart disease. Prolonged anxiety or depression which occurs in distressed people may also increase the risk of heart disease, as well as other ills.
Stress initiates the release of hormones that affect the heart by increasing the heart rate and blood pressure. The heart must, therefore, work harder. In addition, the likelihood of heart attack may be increased by a disturbance of heart rhythm in those people who are susceptible.
Not all stress is bad. There is no doubt that it helps people adapt to threats or changes in their environment. Occasional stress promotes intelligent thinking and planning to assist in fulfilling our needs. It also motivates and encourages resourcefulness. A moderate amount of stress is a normal part of our daily lives, but if we cannot cope with it, it then becomes a health hazard.
Even our stone-age ancestors experienced stress. A time of battle or threat of attack sets off instant survival reactions. This causes changes in body chemistry, increasing alertness, muscular strength, and speed.
In modern urban societies, stresses are felt as a result of economic burdens, difficulties in personal relationships or competition at work or school.
Stress can have a detrimental effect on general health, causing anxiety and depression which results in disturbed sleep, confusion, poor concentration, irritability, uneasiness, loss of interest, loss of appetite, and withdrawal.
The physical signs are headaches, tense muscles, excessive sweating, indigestion, non-specific diarrhea, fatigue, lowered resistance to infections, and viruses.
The effects of stress are an increase in blood pressure, an increase in heart rate, and an increase in the risk of both atherosclerosis and thrombosis.
The best way to avoid harmful stress is to select an environment in line with our instinctive preferences. While we cannot always do this (particularly in our workplace) we can adopt various strategies and skills to protect us from the more negative effects.
4. High blood cholesterol levels
This is a major risk factor. While cholesterol in the body is essential to life, excess cholesterol and fats in the blood contribute to unhealthy arteries. Heart disease may result. Generally, the higher the level of cholesterol in the blood, the higher the risk of heart disease. Diet influences blood cholesterol levels.
Obesity increases the risk of heart disease, mainly by contributing to high blood pressure, high cholesterol levels, and diabetes. People who are more than 20 percent overweight have 3 times the risk of those slightly underweight.
6. Sedentary Lifestyle
Regular exercise strengthens the heart and improves the circulatory system. It also helps control other risk factors (blood fats, stress, and blood pressure). Inactive males have a 2 to 3 times greater risk of heart attack than very active ones.
Exercise also decreases fatigue by increasing physical endurance and reduces muscle tension caused by stress. It promotes a deeper, more restful sleep which is more restorative. It also improves mood, mental concentration, appearance, and self-image.
In simple terms, fitness is having enough energy to perform daily tasks efficiently and with enough energy reserves to enjoy leisure activities. Maximum fitness potential varies from person to person and is largely determined by your inherited constitution. However, regular physical exercise is a factor you have control over.
Age is another factor – people usually have maximum aerobic fitness potential in their early 20s and peak muscular strength at 30.
Heart disease is more common in people with diabetes and often occurs at an earlier age. Most diabetes occurring later in life is triggered by obesity. Diabetics on high fat, low carbohydrate diets are at greater risk of heart disease than those who are on vegetarian-style carbohydrate diets.
8. Hereditary, age, and sex
A family background of heart disease or high blood pressure may increase the risk. The chance of heart disease increases with age. Before the change of life, women are less prone to heart attacks. However, women taking the Pill – especially those who also smoke – are at greater risk.
NOTE: Combined risk factors do not simply add – they multiply the risk. A person with 3 major risk factors is about 10 times more likely to suffer heart disease than his “normal” counterpart.
Recognizing a heart attack
The following symptoms could indicate that a person is having a heart attack:
- Persistent pain, vice-like pressure, a squeezing or burning sensation in the center of the chest, behind the breast bone, or between the shoulder blades.
- Pain may spread to the shoulders, neck, jaw, or arms.
- Sweating, nausea, vomiting or shortness of breath may also occur.
- Sudden collapse or the loss of consciousness.
- Sometimes the pain may subside and return. Symptoms vary from person to person.
If the victim is conscious, go quickly to the nearest major hospital or medical center. Any transport will do if an ambulance or doctor’s car is not available immediately.
Ensure that the victim is seated or reclining, whichever is comfortable. If he or she becomes unconscious, check for breathing and pulse.
Prompt medical care for a heart attack is essential. Even if the symptoms subside, death from heart rhythm disturbances can occur 1 to 2 hours later. Do not let the victim decide against medical care. On arrival at the hospital state clearly that a heart attack is suspected. Ask for prompt attention.
Dealing With Collapse
If you see someone collapse, check first to see whether he or she is conscious. If there is no response, send for a doctor or an ambulance. If you are the only person present do not leave, as emergency action may be required.
Place the collapsed person on his or her back on a hard surface and carry out the following procedure:
- Look, listen, and feel for signs of chest movement and breathing.
- Feel the carotid pulse (neck) to determine whether the person’s heart is circulating blood properly.
This initial check should take no more than half a minute.
- If the breathing and pulse appear normal, keep the person warm, and get medical help.
- If breathing has stopped, start mouth-to-mouth resuscitation. Then check the pulse.
- If the pulse is absent begin heart-lung resuscitation without delay. Your doctor or a qualified instructor from a First Aid group or organization will show you how to do this properly.
The heart is the toughest muscle in the body. It has excellent powers of recovery from heart attack injury. In fact, some heart attack victims become even fitter at work and recreation than ever before, after adopting a corrective lifestyle.
Exercise is important in treating coronary heart patients who feel well and are without symptoms. It may improve their chances of survival. In the early recovery stages, physical activities should be planned in accordance with medical advice. The intensity of activity advised depends on the extent of recovery. Check with your doctor or heart clinic.
Adopt these cautionary tips:
- Avoid lifting or pulling heavyweights.
- Do not exercise within 2 hours of a meal.
- Avoid maximum effort and competitive activities.
Ill-founded fears may lead people unnecessarily to reduce or even abandon sexual activity after a heart attack. The question of sexual intercourse calls for early advice and your doctor or Family Planning Association may be helpful.
- Mental tension and stress should be avoided, so reassess your responsibilities and where possible, lessen them.
- Give up smoking. At worst, smoking can precipitate another heart attack; at least, it reduces the amount of work the heart can perform comfortably.
- Keep alcohol intake down to 1 or 2 glasses of beer or wine with food.
- Get plenty of sleep and rest.