About the Heart
The heart is about the size of a clenched fist and is located between the lungs under the breastbone. It comprises four chambers - two atria and two ventricles - and blood flows through the chambers in a pattern that supplies the entire body with oxygenated blood via a network of blood vessels. The heart pumps with a great deal of force to the arteries which are elastic, enabling them to expand in order to withstand the pressure. After expansion they contract, and this action helps maintain blood pressure and flow. By the time the blood reaches the veins the blood pressure has dropped; the veins are non-elastic but have small valves that keep the de-oxygenated blood flowing back to the heart.
The walls of the arteries can be thickened due to build-up of fatty plaque, resulting in atherosclerosis. As the build up increases and the arteries narrow. A blood clot may entirely block an artery, and depending on the location of the blockage, a stroke or heart attack may occur.
Atherosclerosis of neck (carotid) arteries may affect mental function, and if it occurs in leg arteries peripheral vascular disease with associated intermittent claudication (pain when walking) may result.
Arterosclerosis is the term used to describe the thickening and hardening of arteries that occurs generally with ageing.
A heart attack (myocardial infarction) is a common result of heart disease, and although men and women both have the same number of heart attacks, the incidence for men is actually five times higher than for women between the ages of 35 and 50 years. A heart attack occurs when one of the three coronary arteries is blocked and reduces blood flow to the heart muscle, depriving it of oxygen and resulting in its death.
Symptoms of heart attack include:
- chest pain, often described as "crushing" pain in neck, left shoulder, jaw, left arm or down both arms shortness of breath accompanying pain dizziness, cold sweats and nausea.
The pain associated with shortage of oxygen within the heart muscle is called angina (pectoris) - it is a warning that coronary artery disease is present and usually occurs in middle age men, and both sexes in older age.
Diet and Lifestyle
There are a number of risk factors for cardiovascular disease, including:
- Obesity Diabetes Coronary heart disease in a close relative before the age of 60 Smoking Elevated blood cholesterol and triglycerides Physical inactivity High blood pressure
A preventive strategy for minimising risk would involve basic changes to diet and lifestyle, such as to:
Eat a healthy diet
Implement an appropriate exercise regimen
Eliminate obvious risk factors such as smoking
Maintain a healthy body weight
There is a strong association between diet and cardiovascular disease. The so-called "Mediterranean diet" is high in olive oil, oily fish, fruits, grains, legumes and nuts and is associated with low cholesterol and a lower risk of disease.
Cholesterol is a fat-like substance that performs many important functions within the body but which, in excess produces the fatty plaque that causes atherosclerosis. Cholesterol is transported by lipoproteins within the body and it is the low density lipoprotein cholesterol (LDL) that promotes plaque formation. High density lipoprotein (HDL) cholesterol transports cholesterol to the liver and helps the body eliminate cholesterol. Measurement of blood cholesterol usually includes measurement of HDL and LDL cholesterol, and the LDL to HDL ratio.
Cholesterol is manufactured within the body and occurs in the diet from animal sources - it does not occur in plant foods. Dietary cholesterol can be controlled by healthy eating patterns. Exercise also helps reduce blood cholesterol levels.
In general dietary fats should be reduced to no more than 25% of the total energy intake. Saturated fats (from animals or coconut and palm oils) should be reduced, as should unsaturated fats called 'trans' fats found in pastries and biscuits. These fats increase blood cholesterol and triglyceride levels, and increase blood stickiness, causing blood platelets to clump or aggregate, together. So called 'healthy' polyunsaturated vegetable oils such as safflower and sunflower oils may help to lower cholesterol and reduce the platelet aggregation, however they are more susceptible to oxidation and may lower the good HDL cholesterol.
Olive oil is less likely to be oxidised and is the preferred choice, as is evidenced by the Mediterranean diet.
Dietary fibre, especially the soluble fibre found in fruit and vegetables and in grains such as oats (oat bran) helps to bind fat and cholesterol in the digestive tract and therefore inhibits fat absorption.
Population studies show that those groups who include soy protein in their diet and reduce intake of animal protein have lower blood cholesterol levels and a reduced risk of cardiovascular disease.
Complex carbohydrates from whole foods including vegetables, legumes and grains should be incorporated into the diet, and refined carbohydrates should be reduced. Complex carbohydrates, are more slowly absorbed, helping to maintain steady blood insulin levels and reducing the conversion and storage of sugars to fats.
Diet for a Healthy Heart
- Seasonal fresh vegetables ie leafy greens, green salads, broccoli, zucchini, onions, chinese greens, cabbage (red and white), potato, pumpkin, sweet potato Fresh fruits - any! Fresh herbs for example parsley, coriander, ginger, dill, basil, garlic Sea vegetables (an excellent source of minerals) ie nori, arame, wakame Wholegrain cereals such as rice, oats, wholewheat bread and pasta, millet, buckwheat, barley Deep sea fish - for example trevally, cod, mackerel, salmon, sardines Legumes (these are an excellent source of fibre and protein) lentils, kidney beans, haricot beans, adzuki beans, chickpeas Free range poultry and eggs Soy foods (an excellent source of protein) for example tofu, tempeh Lean red meats 2-3 times per week Nuts and seeds - a small amount can provide beneficial fats and nutrients for example almonds, walnuts, sunflower seeds, sesame seeds Liquids - 6-8 glasses of filtered water per day, green tea, herb teas such as chamomile, peppermint
- Dairy foods should be low fat Refined white flour products - white bread, pasta, biscuits, cakes, sugar. Excess table salt Saturated fats (butter, matured cheeses, fatty meats) and fried foods Coffee, tea, colas and other stimulants should be kept to a minimum.
Exercise for a Healthy Heart
Exercise is extremely important for the maintenance of a healthy cardiovascular system and should be part of the daily regime.
You should aim to achieve a heart rate during exercise of 70% of your maximum heart rate for age. The maximum heart rate for age is calculated by subtracting you age from 220 ie if you are 50 years of age, your maximum heart rate for age would be 170 BPM (beats per minute). 70% of this is 119 BPM and this should be maintained for around 20 minutes daily. Before undertaking any exercise check with your healthcare practitioner.