Here is What You Need To Know About Your Heart


July 6, 2017 Facebook Twitter LinkedIn Google+ LIfestyle



Romantics say the heart is a mysterious thing. But when you’re worried about developing high cholesterol or blood pressure, you don’t want mystery—you want answers. Here are clear and useful answers to some important questions about heart health.

WHAT DOES THE HEART LOOK LIKE?

Surprisingly small, an average heart is roughly shaped like an upside-down pear. It weighs around 300 grams and is about the size of a clenched fist. The largest arteries in the body, the coronary arteries, sit on top of it like a crown.

The heart has four chambers. The two upper chambers are the atria, and they receive and collect blood. The two lower chambers are the ventricles. They pump blood to other parts of your body. Inside the heart are valves. They act like traffic police to keep blood flowing in the right direction.

On average, it pumps more than 2.5 billion times in a lifetime without resting. Every minute of every day, it pumps nearly 4.3 litres of blood around your body through a series of tubes (blood vessels), large and small, that measure more than 96,000 kilometres.

Yes, you read that right. Your arteries, veins and capillaries, which carry blood enriched with oxygen and nutrients to all your organs and tissues plus take away waste for disposal, would circle the Earth twice!

HOW DOES IT WORK?

The heart has an electrical system (called the cardiac conduction system) located in your heart muscle. This can be monitored by a common heart test called an electrocardiogram, or ECG. This electrical system triggers your heart chambers to contract and relax to pump blood through your cardiovascular system.

It’s a complex process; blood that is depleted of oxygen enters the atrium on the right side of your heart. It then passes to the right-side ventricle; when the valve to the atrium closes, the ventricle pumps the blood to your lungs. There, carbon dioxide in your blood is removed (then exhaled away) and fresh oxygen is picked up. The replenished blood then flows into your heart’s left atrium, which passes it to the left ventricle, which then pumps it into the aorta. From there, the blood flows through your body, delivering oxygen and fuel in the form of blood glucose, which is picked up farther downstream, via the digestive system.

Ultimately, the oxygen-depleted blood returns to your heart, where it cycles through again and again in a continuous, life-sustaining cycle. Your heart contracts and relaxes roughly 80 times per minute!

HOW DO ARTERIES GET BLOCKED?

Blockages start in a small way with tiny changes in the walls of arteries. These changes set off a process by which fats called lipids—together with cholesterol, calcium and other substances in the blood—are sucked into the arterial lining. This process may have started when you were a child or a teen, depending on what you ate, how active you were and your genetic risk.

Gradually these fatty deposits build up and cause a narrowing of the inside of the arteries, which in turn restricts blood flow. At the same time, these deposits may harden, making the walls of your arteries thicker and less flexible so that they are less able to expand and contract to regulate blood flow. This means that when you run, for example, your arteries can’t widen to allow more oxygen-rich blood to flow to your muscles. You may get out of breath quickly or start to experience chest pains. The medical term for this is, atherosclerosis, although it is frequently described as “furring up” or “hardening” of the arteries. The substance that adheres to the arterial walls is called plaque.

There are several types of heart disease. But in most cases, the main cause is directly linked to this process that starts in your arteries.

WHAT CAUSES FATTY BUILD-UP IN THE ARTERIES?

Some people are born with genes that make their bodies produce more cholesterol, blood that’s more likely to clot or artery walls more prone to damage. But largely, fatty buildup is related to how you live, what you eat, whether you’re overweight or normal weight, if you smoke, how much you exercise and how you handle stress. Yes, it’s mostly on you. But that’s a good thing. It means that you’re at an advantage—you can make changes that can reduce or even eliminate your risk of having a heart that’s not healthy.

HOW DOES WHAT I EAT AFFECT MY HEART?

The fatty deposits come from somewhere, and it’s usually from your plate. A diet high in saturated fat—from meats and dairy products—and low in fruit and vegetables is associated with unhealthy hearts.

ARE WE TALKING ABOUT CHOLESTEROL?

The first thing to know is that cholesterol isn’t all bad. Your liver makes it because your body needs it for various functions. Usually, your liver makes just enough to serve your body’s needs. But when you eat too much saturated fat, your body starts making excess cholesterol—the kind that clogs up your arteries.

Cholesterol in the blood takes the form of small packages called lipoproteins, made up of lipids (fats) and protein. There are two kinds in your bloodstream: “bad” LDL (low-density lipoprotein) cholesterol and “good” HDL (high-density lipoprotein) cholesterol. Too much LDL—the result of too many steaks and rich desserts—increases the risk of atherosclerosis, the narrowing of the arteries that can lead to heart attacks and strokes.

But HDL cholesterol—the result of healthy ingredients in your diet such as olive oil and nuts—carries LDL cholesterol back to the liver for reprocessing. That means HDL may protect the heart.

If you have a high level of LDL cholesterol in your blood, the low-density lipoproteins can begin to stick to the artery walls. This buildup contributes to the formation of a plaque, a hardened lump on the side of your arteries that makes arteries narrower so blood can’t easily pass through to supply oxygen and nutrients. Plaque is sticky, like flypaper, so it attracts even more plaque and a vicious circle begins.

WHAT IS METABOLIC SYNDROME?

This little known but widespread condition is actually a cluster of conditions that together greatly increase heart disease, diabetes and stroke risk. You know many of the individual conditions already: being overweight, high blood pressure, unhealthy cholesterol numbers, high blood glucose. Fat itself is the driving force of metabolic syndrome. Stomach or visceral fat pumps chemicals into the bloodstream, including immune system messengers called cytokines. The constant flood of cytokines interferes with the absorption of blood glucose by muscle and liver cells. Basically, cytokines block signals from insulin to cells to let sugar in. Now you’ve got cells that have no fuel and blood glucose building up in the bloodstream—two dangerous situations. Your pancreas responds by producing more insulin.

Metabolic syndrome can quadruple heart attack risk. Here’s why: In people with metabolic syndrome, insulin levels can rise two to three times higher than normal, and they can stay elevated for decades. All that excess insulin is a setup for heart disease. It boosts levels of triglycerides in your bloodstream, lowers levels of “good” HDLs and ensures that above-normal amounts of fat end up in your bloodstream after a meal and stay there longer. Insulin also morphs “bad” LDLs into smaller, denser particles that can easily burrow into artery walls and form the bedrock for plaque. Additionally, it boosts concentrations of a substance called fibrinogen in the bloodstream, making your blood more likely to clot.

ARE TRIGLYCERIDES ANOTHER FORM OF CHOLESTEROL?

Triglycerides are not a form of cholesterol, but because they act in a similar way and have similar effects, they are often grouped with cholesterol in many discussions about heart risks.

Triglycerides are bits of fat in the bloodstream that collect excess calories from the food you eat and whisk them away to fat cells for storage. Triglycerides can also become the raw material for LDLs. Studies suggest that triglycerides alone can predict heart risk, since they encourage atherosclerosis, especially in women.

IF I’VE BEEN DIAGNOSED WITH HEART DISEASE, IS IT EVENTUALLY GOING TO KILL ME?

The answer is no, it’s not inevitable, as long as you start to adopt healthy lifestyle habits. The World Health Organization estimates that at least 80 per cent of premature deaths linked to heart disease could be prevented by adopting simple measures such as eating a healthy diet, exercising moderately and regularly, and not smoking.

WHAT ABOUT MY FAMILY HISTORY?

Having a family history of heart disease does statistically increase your risk of developing a problem yourself. And the closer the relative is to you, the higher the risk. If your dad or mom died of heart disease, you may want to talk to your doctor about your potential risks and arrange to get your cholesterol and blood pressure checked regularly. But here’s an important point: genetics is a small predictor of future heart disease. As you just read, how you live each day is far more important. Studies suggest that lifestyle choices are the real cause of 80 per cent or more of heart attacks.

COULD I HAVE A HEART ATTACK OR STROKE EVEN IF MY CHOLESTEROL LEVELS ARE NORMAL?

Remember that cholesterol is only part of the story: in recent years, scientists have found other health issues that play a major role in heart disease. Some of these issues work in tandem with cholesterol to raise your risk, while others cause trouble all by themselves. They include inflammation, for example.

The inflammatory process, which is started by your immune system to help repair and protect a wound, kicks in when that “wound” is a plaque in your arteries. It works fine, if it only occurs while the wound is healing. But when inflammation becomes chronic (the medical term for an ongoing condition), it becomes a problem. Rather than protecting your arteries, it damages them and makes them more prone to plaque build-up.

WHAT CAN CAUSE CHRONIC INFLAMMATION?

Things such as high blood cholesterol, but there are other risk factors as well. They include having high blood pressure, being overweight or obese (particularly if your fat is around your stomach) and having type 2 diabetes. At high levels, inflammation can double or even quadruple the risk of heart attack. Think of inflammation as your body’s “home security system.” There are many things that can set it off. Get a mosquito bite, it inflames as your immune system seeks to neutralize and heal the spot that’s been bitten. That’s the system working properly; the problem lies with the triggers that cause inflammation to turn on and stay on.

What causes this? Many of the traditional risk factors linked to heart attacks and strokes, such as high blood cholesterol levels, high blood pressure, diabetes and obesity, also provoke inflammation. Those risk factors may be created by visceral fat, a glut of calories, the wrong foods (fast foods), lack of exercise and even daily stresses, such as a traffic-snarled commute.

Inflammation also can be turned on long-term by low-grade infections, such as gum disease. This is just another reason why brushing and flossing are so important. Also, we’re living longer than ever in human history; so our bodies’ aging tissues are exposed to inflammation’s chemical irritants longer and therefore sustain more damage.

IS THERE ANY WAY TO BEAT INFLAMMATION?

Eating plenty of fish and taking an omega-3 krill oil supplement, having higher levels of vitamin C and losing weight have been linked with lower C-reactive protein (CRP) levels. CRP increases when inflammation is present and can be valuable in monitoring disease activity. There’s a test that measures the heart-damaging CRP in your body.

Regular exercise makes a difference as well. One study of 452 men found that white blood-cell counts were lowest in men who were physically fit and highest in those who were most overweight. That’s noteworthy, because white blood-cell counts are another indicator of inflammation levels. On average, the higher a man’s proportion of body fat, the higher his white-cell count, supporting evidence that fat cells produce inflammatory chemicals. The researchers also noted that being fit, seemed to counteract the effect of extra fat, suggesting that fitness plays a large role in combating inflammation.

IS “CORONARY ARTERY DISEASE” THE SAME AS HEART DISEASE?

No. Coronary artery disease, or CAD, is one specific type of heart disease. CAD affects the arteries that directly supply oxygen to your heart. Remember, your heart is a muscle that itself requires lots of oxygen and fuel to operate. That’s why it has so many large coronary arteries surrounding it. CAD is caused by a buildup of plaque inside the larger arteries that feed your heart. The narrowed arteries can’t supply sufficient oxygen-rich blood to the heart muscle to cope with periods of higher demand, such as during exercise.

DOES CORONARY ARTERY DISEASE EVER HAVE WARNING SYMPTOMS?

One common symptom is pain or discomfort in the chest, known as angina. If you have angina, your heart desperately craves more oxygen and fuel to operate at times of increased demand or stress. The symptoms are like a muscle cramp you can get after a run up three flights of stairs or a day of tennis. With angina, the sensation of heaviness or tightness in your chest may spread to your arms, neck, jaw, back or stomach. Angina means your arteries are becoming blocked, and it’s time to consult your doctor about lifestyle changes—and medications—that will help unblock them.

WHAT EXACTLY IS A HEART ATTACK?

The medical term for a heart attack is myocardial infarction, which indicates that some of the cells in the heart muscle (myocardium) have died because of a lack of blood supply (infarction).

WHAT’S THE MOST COMMON CAUSE OF HEART ATTACK?

The most common cause of a heart attack is a blood clot that completely blocks a coronary artery, cutting off the blood supply to the heart. Scientists now know that so-called “soft” plaque is the dangerous trigger—it’s responsible for about 85 per cent of all heart attacks. The plaque you usually hear about is “hard” plaque. Hard plaque contains more calcium and can grow relatively larger, narrowing arteries, restricting blood flow and causing chest pain or high blood pressure.

By contrast, soft plaque, which causes less narrowing but is loaded with fatty deposits, can easily rupture without warning, like an explosion in your blood vessels. A rupture causes those blood fats and other debris to spill out from the artery wall and trigger the formation of a clot that could block vital blood flow to an area of the heart muscle, damaging it and even causing some of the muscle tissue to die.

IF I HAVE A HEART ATTACK, WHAT ARE MY CHANCES OF SURVIVAL?

In the worst case, the heart stops beating altogether and goes into cardiac arrest. But, with rapid treatment, damage to the heart muscle can be halted and, if blood flow is restored in time, you can have a full recovery. Research has shown that treatment started within an hour of the onset of symptoms reduces the risk of death and lessens heart damage. People who receive help within this time frame are three times more likely to survive a heart attack.

DOES A HEART ATTACK PERMANENTLY DAMAGE MY HEART?

It can. If you don’t get prompt treatment or if damage to your heart can’t be halted in time, a part of your heart muscle will be permanently scarred and damaged. If the scar tissue is extensive, you can experience long-term breathing problems. Sometimes a heart attack can disturb the flow of electrical impulses that normally generate your heartbeat to circulate blood around your body. If this happens, you could develop heart-rhythm abnormalities, known as arrhythmias.

Arrhythmias are most common in the first three to six hours after an attack. Some are mild, but they can cause palpitations (an irregular heartbeat that can feel like fluttering in your chest), dizziness, chest pain, shortness of breath or fatigue. Others can be life-threatening.

If damage to the heart muscle is extensive, you may develop heart failure. This occurs when your heart can’t pump strongly enough to propel blood around your body. As fluid accumulates in your lungs, you’re likely to have breathing problems. The condition is called congestive heart failure.

WHAT IS A STROKE?

A stroke is like a heart attack in your head. There are two main types. Many strokes, called ischemic strokes, are caused by a clot blocking a blood vessel. The clot may have formed following a rupture of plaque, as happens in the most common kind of heart attack; more often, it may have travelled through the bloodstream from elsewhere in the body. Clots that move through the bloodstream in this way are known as emboli, and when they lodge in the brain, the event is called a cerebral embolism.

Approximately one in five strokes is due to bleeding in the brain, following the tearing of an artery wall. Known as a hemorrhagic stroke and might easily occur in someone with high blood pressure. The effects of a hemorrhagic stroke are often more severe than those of ischemic stroke. In both cases, the result is similar: blood supply is cut to brain cells that control functions such as speech or movement. If the brain cells die, it can lead to permanent disability.

You can also have something called a transient ischemic attack (TIA), or mini-stroke.

CAN STROKES BE PREVENTED?

Like heart attacks, strokes are largely preventable. Stopping smoking, reducing blood pressure, losing weight and exercising can drastically reduce risk, just as they can for heart disease. A landmark 2009 study involving more than 20,000 adults revealed that people who either smoked, drank excessively, were inactive or ate few or no fruits and vegetables were twice as likely to suffer a stroke as people who had healthier habits.

HOW DOES STRESS AFFECT MY HEART?

Uncontrolled stress not only increases levels of the hormone cortisol, which directs fat storage straight to your waistline, it also makes you more likely to overeat refined foods that trigger feel-good hormones. Chronic stress can also boost your blood pressure. In one study, people who said they usually felt pressed for time, ate too quickly and got upset easily, were twice as likely to develop hypertension.

Mental stress also impairs the endothelium, the protective barrier that lines your blood vessels, which paves the way for a series of inflammatory reactions that lead to fat and cholesterol buildup in the coronary arteries and ultimately a heart attack.

Stress can also make you fat. Uncontrolled stress increases levels of the hormone cortisol, which directs fat storage straight to your waistline. Cortisol makes you more likely to overeat, especially comfort foods such as chips and cookies, which trigger feel-good, tension-lowering hormones.

The correlation between emotional health and heart health is indisputable. Studies show that depression can double your risk of developing coronary artery disease or having a heart attack. Anger, impatience and hostility significantly raise your risk of heart disease. In one study, people who scored highest for feelings of hostility had an 84 per cent greater risk of developing high blood pressure than those who scored lowest.

IS STRESS AS BAD AS OTHER HEART DISEASE RISK FACTORS?

It’s right up there. We know that, in part, from what happens to people when they find a way to cut their stress levels. In one study, people with heart disease who found ways to manage their stress were 74 per cent less likely to have a heart attack or need bypass surgery.

CAN WE HALT OR REVERSE THE PROCESS THAT CAUSES CARDIOVASCULAR DISEASE?

Absolutely! Much heart disease is preventable because most of its causes are linked to lifestyle. In fact, the Interheart study identified nine factors that accounted for 90 per cent of first-time heart attacks.

WHAT ARE THE NINE FACTORS?

They are abnormal blood fats, smoking, high blood pressure, diabetes, stress, obesity (especially stomach fat), eating too few fruits and vegetables, lack of daily exercise and excess alcohol intake.

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