What 'pressure' is and why it kills

What is 'high blood pressure'? What causes it? And why is having normal blood pressure so important?

The National Heart Lung & Blood Institute describes "blood pressure" as the force of blood pushing against the walls of arteries as the heart pumps. If blood pressure rises and stays high over time, it becomes 'hypertension', which can damage the body seriously.

For more answers we turned to Dr Gerald Grell, an internal medicine specialist with vast experience and unquestionable expertise.

The 'normal blood pressure range' starts from 120/80, he said. Doctors diagnose stage-1 hypertension when someone's blood pressure level hits a danger zone starting at 140/90.

This diagnosis is confirmed when blood pressure is 140/90 or above at least twice in succession.

Hypertension is associated with obesity, excessive alcohol use, diabetes, high salt consumption, smoking and stress, Dr. Grell said.

Untreated or poorly controlled hypertension can cause kidney damage, renal failure requiring dialysis—even death!

However, Dr. Grell said there are many "essential hypertension" cases with no detectable underlying cause, but the afflicted persons have a family history of hypertension.

He added that hypertension from 'preeclampsia' often occurs during pregnancy and this generally ends after the baby is delivered.

Dr Grell commented that 'black' populations seem susceptible to hypertension and CARICOM countries, with help from PAHO/WHO, have installed networks of clinics and services for the diagnosis, treatment, and follow-up of hypertension.

He theorizes that the bodies of dark-skinned people from hot countries are genetically adapted to retain salt, which helps them function better when they sweat excessively. But this is a mixed blessing as it makes them vulnerable to hypertension.

In contrast, light-skinned persons from cold regions tend to have lower heat tolerance because their bodies lose salt faster. They are more likely to faint in hot conditions, but are less susceptible to hypertension.

Untreated or poorly controlled hypertension is the basis of major non-communicable diseases (NCDs) -- like renal failure requiring dialysis; stroke; heart attack and heart failure.

In many cases, NCDs are inter-related; hypertension can cause kidney disease or kidney disease can cause hypertension, Dr Grell said.

"Bad kidneys can cause the body to retain sodium and send up your pressure. But if your pressure remains up, it will damage the kidneys even further, resulting in the need for dialysis," he explained.

In his experience, women take better care of their general health and blood pressure than men, so most of the dialysis patients at the Princess Margaret Hospital are men.

Dr. Grell recalled that some drugs formerly used to treat hypertension caused sexual dysfunction in some men. This no longer happens with modern drugs, yet many men are still reluctant to use them because they fear becoming impotent.

"Most of the people on dialysis are men . . . because men usually do not take their medication regularly and do not repeat the prescriptions," the doctor observed.

He insisted that only way to know one's blood pressure level is to measure it with a blood pressure machine; therefore, it is extremely dangerous when patients stop taking their pills once they feel ok.

Dr. Grell stressed that patients are dangerously wrong to assume that their blood pressure is ok once they feel well; it cannot be ok unless it's measured with a blood pressure machine.

He said hypertension patients must get their blood pressure regularly checked and recorded at Government clinics, doctors' offices, or by several nurses who provide excellent follow-up service in Dominica.

Another serious complication of hypertension is an enlarged heart, which Dr. Grell said occurs when the heart constantly pumps at a higher pressure than it should.

"If I lift dumbbells weighing say 40 pounds every day, then I will, in time, increase my muscle size…" Likewise, a heart pumping blood against a high weight or pressure can become enlarged then heart failure can occur, he explained.

Increased blood pressure can affect the brain too, he said, delicate blood vessels can rupture within the skull resulting in a stroke.

Longstanding hypertension narrows blood vessels and diminishes blood flow, the doctor warned. When complete obstruction occurs, this can trigger a myocardial infarction (heart attack), and what is called a thrombotic stroke (of the brain).

Cholesterol-- essentially fat in the blood-- also blocks hypertensive patients' blood vessels, creating a thick layer of fat on the inside walls. This obstructs the vessels in the brain or the heart and thrombotic strokes or heart attacks can occur.

Dr. Grell said it is imperative that hypertensive patients check their cholesterol levels along with their blood pressure, and try to keep both down.

He urged hypertensive patients to keep their blood sugar, blood cholesterol, and blood pressure levels under strict control through lifestyle changes and appropriate medications.

Such lifestyle changes include reducing salt intake, losing weight, and eliminating alcohol consumption and smoking.

Medication is also important for relaxation, de-stressing, a feeling of well-being and peace of mind-- all of which contribute towards better control of hypertension, the doctor advised.

He noted that drug therapy is the mainstay of modern treatment of hypertension -- in communities, emergency rooms, hospital wards, during surgery, at work or at play.

Several effective antihypertensive drugs are now available, Dr Grell said, and doctors can be trusted to select the most appropriate drug or combination of drugs for specific patients. He maintained that all decisions about antihypertensive drugs must be left to medical professionals who will assess patients' risks and associated conditions before prescribing treatment.

Such professionals will choose medicines and adjust dosages for optimal control of patients' blood pressure, to keep their laboratory profiles relatively normal, so they can live safe, risk-free lives.