High Blood Pressure

High Blood Pressure And Diabetes: Double Trouble?

Dr. S.M.Sadikot.
Hon. Endocrinologist,
Jaslok Hospital and Research Centre,
Mumbai 400026

Diabetes and high blood pressure (hypertension) are serious disorders. Each of them can lead to severe complications in the body and in many cases they affect the same organs. Thus, one would naturally assume that if one has diabetes and high blood pressure, the ill effects in the body would be double.

Right?………………Wrong!

Having diabetes and high blood pressure is not a case of adding one and one and making two. It is more like eleven! The ill effects of diabetes and high blood pressure, when a person has both, are increased much more than one would imagine.

The problem is that many patients with diabetes also have high blood pressure! It has been estimated that high blood pressure is twice as likely to be present in a person with diabetes as compared to someone who does not have diabetes.

In order to understand the problems which high blood pressure can cause, it would seem proper to learn a little bit about blood pressure.

The various parts of the body need nourishment. They get this from the blood that flows to them in the arteries supplying the various parts of the body. The heart "pumps" the blood into the arteries, but for the blood to flow through the arteries, especially the smaller vessels, it literally has to force apart the walls of the arteries, so that it can pass through. It is this pressure which the blood has to apply to the arteries to allow it to flow through which is called "blood pressure".

Thus, one could say that it mainly depends on the resistance offered by the arteries to the blood flow and will also depend on the amount of blood which has to flow. This again is obvious. If more blood has to flow the walls of the arteries have to be kept open wider and for a longer time period. Thus, the heart will have to pump that much harder!.

Heart Pump

Basically, when your doctor tells you about the upper and lower pressure readings, he is talking about what we call the "Systolic" and "diastolic" blood pressure readings.

Although most of us do not realize it, the heart pumps blood more than 100,000 times a day! Each time it beats, a blood is pumped into the arteries and this blood has to overcome the resistance of the vessels. This gives rise to the upeer or the higher reading which is the systolic pressure. In between heartbeats, when the blood flow decreases in the arteries, the pressure on the walls is lowered and this gives rise to the lower or the diastolic pressure readings.

That is why blood pressure is reported as two numbers, e.g., 120/80. The first, higher number (systolic) is the pressure of the blood against the artery walls when the heart contracts (e.g., 120). The second, lower number (diastolic) is the pressure against the artery walls when the heart relaxes between beats (e.g., 80).

Desirable Blood Pressure 120 Systolic
For Healthy Adults 80 Diastolic

Any blood pressure reading that consistently stays at 140/90 or higher is considered high blood pressure.

For diabetic subjects high blood pressure is defined by a blood pressure up to 130/85 mmHg, or 120/80 which is better still, especially if they have kidney dysfunction.

We have seen that the blood pressure depends on the resistance offered by the arteries to the flow of blood. If the vessels are wider ( more "open") then, the heart has to do less work in pumping the blood through. But if for some reason, the same vessels become smaller, more pressure is needed for the same amount of blood to flow through them. This increase in pressure, which is more than normally required, is called high blood pressure.

Blood Pressure Blood Pressure

In the vast majority of cases, we do not know the reason and the high blood pressure is called "essential" hypertension. In a few cases, especially in those who are young, it is possible to find a cause leading to the high blood pressure and in these people are said to have "secondary" hypertension.

Although a lot of research is being carried out on why people with diabetes are at a higher risk for having high blood pressure, we are still to arrive at any definite answer.

But the fact remains that high blood pressure is much more common in a person with diabetes and that together they are a very deadly "duo" unless both, diabetes and the high blood pressure are well treated and kept at optimal levels.

  • People with close blood relatives who have it. It "runs" in families.
  • People with diabetes.
  • People over 30. although more and more younger people are seen to have it.
  • Overweight people, especially those who have a high waist to hip ratio.
  • People who use too much salt.
  • People who use too much alcohol.
  • Women who take birth control pills.
  • People who aren't active.
  • Pregnant women.
  • Atherosclerosis ( blocking or narrowing of the vessels)
  • Stroke
  • Heart attack
  • Heart failure
  • Kidney failure

Arteriosclerosis is hardening of the arteries. The walls of arteries have a layer of muscle and elastic tissue that makes them flexible and able to dilate and constrict as blood flows through them. When your blood pressure remains high for a long period of time, these vessel walls get affected and become harder and less flexible. They are unable to dilate when the heart pumps blood and more blood has to pass through. Similarly, in the diastolic phase, when the walls have to get back into their normal shape. More often than not the net results is a narrowing of the vessels. This also leads to damage to the inner linings of the arteries. Cholesterol and fats are more likely to build up on the walls of damaged arteries, making them even narrower. Blood clots can also get trapped in narrowed arteries, blocking the flow of blood.

Arteries narrowed by arteriosclerosis may not deliver enough blood to organs and other tissues. Reduced or blocked blood flow to the heart can cause a heart attack. If an artery to the brain is blocked, a stroke can result.

Hypertension makes the heart work harder to pump blood through the body. The extra workload can make the heart muscle thicken and stretch. When the heart becomes too enlarged it cannot pump enough blood. If the hypertension is not treated, the heart may fail.

The kidneys remove the body's wastes from the blood. If hypertension thickens the arteries to the kidneys, less waste can be filtered from the blood. As the condition worsens, the kidneys fail and wastes build up in the blood.

When you read the consequences of high blood pressure, you will realize that many of these are very similar to those caused by diabetes. So, if a person has both high blood glucose as well as high blood pressure, the problems get multiplied!

Not only is the atherosclerosis more severe, it occurs at a much earlier age and progresses much faster when one has both diabetes and high blood pressure. Is it any surprise that heart problems and paralytic strokes are so much more common in people with diabetes who also have high blood pressure!

We have seen that foot problems are very a very serious complication in a person with diabetes. Narrowing or complete blocks of the arteries going to the feet does not allow blood to flow to the feet which is an important factor in ulcers of the feet not healing well and leading to increased numbers of amputations. Gangrene of the leg, often precipitated by an infection, is also more common, increasing the numbers of people who have to undergo amputations.

We know that diabetes affects the small vessels (diabetic microangiopathy) which is involved in causing the eye and kidney problems in patients with diabetes. The presence of high blood pressure in people with diabetes, increases these eye and kidney problems in "leaps and bounds"!

The kidneys merit a special mention. Not only does high blood pressure and diabetes lead to kidney damage, but the kidney damage itself leads to an increase in the blood pressure levels. You can imagine the viscious cycle. The kidneys are damaged by the high blood glucose levels and the high blood pressure and this damage, in turn, increases the high blood pressure!

As importantly, when the kidneys are damaged, the control of the blood glucose levels becomes very difficult with a tendency for the blood glucose levels to fluctuate from very high to very low blood glucose levels without any "apparent" cause. The fluctuations, the high blood glucose levels and the "hypos" that occur increase the damage not only to the kidneys but the other organs which are "targeted" in diabetes.

Unfortunately, most people have no obvious symptoms and only come to know of it after they have suffered from some complications.

The only way to know if your blood pressure is high is to get it checked regularly by your doctor. This is especially true when you have diabetes.

Your doctor will always measure your blood pressure and you too, must go regularly to your doctor to measure the pressure even though you may be feeling "fine"!

Because hypertension doesn't cause symptoms, it is important to have blood pressure checked regularly. Blood pressure is measured with an instrument called a mercury sphygmomanometer. This is something all of you are familiar with. You must have seen your doctor use it so often and possibly, he may have even used it on you.

A cloth-covered rubber cuff is wrapped around the upper arm and inflated. When the cuff is inflated, an artery in the arm is squeezed to momentarily stop the flow of blood. Then, the air is let out of the cuff while a stethoscope placed over the artery is used to detect the sound of the blood spurting back through the artery. This first sound is the systolic pressure, the pressure when the heart beats. The last sound heard as the rest of the air is released is the diastolic pressure, the pressure between heart beats.

Sphygmomanometer

Many doctors now use a device called the aneroid meter. This type of device does not contain mercury. A metal membrane located in a case translates the blood pressure transmitted by the cuff. This type of device is very practical to use and is generally reliable if it is regularly controlled.

This method constitutes a good alternative to the sphygmomanometer with mercury.

Aneroid sphygmomanometer
  • Lifestyle changes· Take medicine the way your doctor tells you.
  • See your doctor regularly.
  • Know what your blood pressure should be and work to keep it at that level.

There is no cure for primary hypertension, but blood pressure can almost always be lowered with the correct treatment. The goal of treatment is to lower blood pressure to levels that will prevent heart disease and other complications of hypertension.

Initially your doctor may just ask you to take certain steps which are called as lifestyle modifications. Most of these changes are similar to those which you may have been asked to make because of your diabetes.

Lifestyle changes that may reduce blood pressure by about 5 to 10 mm Hg include:

  • Weight control
  • Reducing salt intake
  • Reducing fat intake
  • Getting regular exercise
  • Quitting smoking
  • Reducing alcohol consumption
  • Managing stress

Controlling your weight is a very important step that you can take to reduce your high blood pressure. Losing just a few extra pounds can help lower your blood pressure. Research has shown that weight reduction, even as little as 10 pounds reduces blood pressure in a large percentage of overweight persons with hypertension, makes blood pressure medications more effective and reduces cardiovascular risk.

Whilst all weight loss in a person who is overweight will help, your doctor may prescribe exercises which decrease "central" obesity, or waist size as most call it.

Your diet will also need to be further modified. You will have to control the amount of salt and fats which you eat. Recently, one diet which has been found to be very effective in people with high blood pressure. It is called the DASH diet.

The DASH eating plan significantly lowered blood pressure in the recent Dietary Approaches to Stop Hypertension (DASH) study, and it may also help prevent and control high blood pressure.

Dash Eating Plan

Food Group Daily Servings* Serving Sizes
Grains 7-8 1 slice bread; ½ cup cereal or cooked rice, pasta, or cereal
Vegetables 4-5 1 cup raw leafy vegetable; ½ cup cooked vegetable; 6 ounces vegetable juice.
Fruits 4-5 1 medium fresh fruit; ¼ cup dried, frozen, or canned fruit.
Low-fat and nonfat dairy 2-3 8 ounces milk; 1 cup yogurt; 1.5 ounces cheese.
Meats, poultry, and fish 2 or fewer 3 ounces cooked meat, poultry, or fish.
Nuts, seeds, and legumes Fewer than 1 (4-5 per week) 1.5 ounces or 1/3 cup nuts; ½ ounce or 2 tablespoons seeds; ½ cup cooked legumes.
* Number of servings is based on eating 2,000 calories a day. If your caloric needs are higher or lower, you may eat more or fewer servings.

You should remember that you still have to follow the diet which your doctor has prescribed to you for your diabetes. So please discuss the DASH diet with your doctor and see how it fits into your diet plan.

For some of you, your doctor may prescribe tablets along with the lifestyle changes. Even in some of you who have only been advised to make some lifestyle modifications, your doctor will monitor your blood pressure closely.

Patients, with diabetes, whose blood pressure remains higher than 120/80 may be asked to take medications to further lower their blood pressure.

Numerous drugs have been developed to treat hypertension. The choice of medication will depend on the degree of high blood pressure, the side effects, the presence of other medical conditions besides the diabetes, as well as other medicines you may be taking.

Please do not take any medications unless it has been prescribed by your doctor. You must understand that many of these medications may not be good for your diabetes and so your doctor will carefully choose and monitor the effects of the medicines which are prescribed to you.

Follow instructions carefully. Many drugs do not work properly unless you take them exactly as directed.

Your doctor will tell you the side effects which you should look out for. Watch carefully for any of these and if they do occur, report them to your doctor immediately.

Some of the commonly used drugs for treating high blood pressure are

High Blood Pressure Drugs

Diuretics Sometimes called "water pills," they flush excess sodium and water from the body through the urine, lessening the amount of fluid in the blood.
Beta-blockers They make fewer nerve impulses happen in the heart and blood vessels. This slows the heart, which beats less often and with less contracting force-so blood pressure drops and the heart doesn't work as hard.
ACE inhibitors(angiotensin- converting enzyme) and ARBs (angiotensin receptor blockers) They block the formation or the action of a hormone made in the kidney. The hormone narrows the blood vessels and causes blood pressure to rise.
Calcium channel blockers By barring calcium from entering the muscle cells of the heart and blood vessels, they make the blood vessels relax.
Alpha-blockers They work on the nervous system to relax the blood vessels, letting the blood pass more easily.
Nervous system inhibitors By controlling nerve impulses, they relax blood vessels.
Vasodilators They open blood vessels by relaxing the muscle in the vessel walls.
Most Importantly

Do not stop taking medication or cut down without prior approval from your doctor. Many patients when they see that the blood pressure is "controlled" stop taking the medications.

Please do NOT do this.

Abruptly stopping medication may result in rapid rise in blood pressure.

It is TRUE that high blood pressure is much more common in people with diabetes.

It is TRUE that both together can lead to serious complications;

BUT

It is also TRUE that high blood pressure can be kept under tight control; and

It is also TRUE that YOU have the major role to play in controlling it!