High Blood Pressure or Hypertension is a common finding among adults and is the greatest contributor to heart disease, premature death and disability from cardiovascular disease, worldwide. Hypertension and Coronary Artery Disease are the main causes of heart failure, and high blood pressure is the main risk factor for stroke. Additionally hypertension increases the cardiovascular [...]

The Sundaytimes Sri Lanka

Are you checking your blood pressure?

Control your blood pressure and heart rate to live longer

High Blood Pressure or Hypertension is a common finding among adults and is the greatest contributor to heart disease, premature death and disability from cardiovascular disease, worldwide. Hypertension and Coronary Artery Disease are the main causes of heart failure, and high blood pressure is the main risk factor for stroke. Additionally hypertension increases the cardiovascular risk of diabetes, high cholesterol, cigarette smoking and obesity. Prevalence of hypertension increases with age and along with diabetes contributes to kidney disease .Maintaining blood pressure in the normal range reduces the incidence of dementia and Alzheimer’s disease.

Maintaining blood pressure in the normal range reduces the incidence of dementia and Alzheimer’s disease. File pic

A high heart rate can aggravate angina and worsen heart failure. Since the heart is a pump, a high blood pressure and heart rate can increase the work of the heart and lead to heart failure. Recent research has shown that a lower resting heart rate prolongs longevity. Animals with the lowest heart rate like the elephant and the blue whale live the longest. By certain estimates human hearts can wear out after 2 billion heartbeats for an average life span of 70 years.

If your heart rate is 70 instead of 60 it has to beat 14,400 more times each day. In my opinion a high resting heart rate is an important risk factor for heart disease and should be controlled. Drugs that exclusively lower the heart rate are now available and should be considered if the heart rate remains persistently above 70 beats per minute.

One of the most important factors in the under recognition of hypertension is that hypertension is a silent disease and the majority of people do not feel unwell even if their blood pressure is high. Therefore an accurate measurement of your blood pressure is crucial before a diagnosis of hypertension is made.

Traditionally blood pressure is obtained by the doctor in his clinic. The patient should be seated with both feet resting on the ground with the arm supported at heart level, after resting for five minutes. A minimum of two readings should be taken and averaged. Errors in positioning the patient, incorrect cuff size relative to arm circumference and recent intake of caffeine and cigarette smoking contribute to variations in blood pressure recordings. Blood pressures measured by doctors tend to be higher than done by other health care personnel (white coat hypertension). Repeated blood pressure measurements by different physicians may be helpful in obtaining accurate data before making treatment decisions.

Increasing use of electronic blood pressure measuring devices by patients help to reduce this variability with a reasonable degree of accuracy. These values should be double checked with a known reliable instrument if they are to be used in making treatment decisions – Classification of hypertension is based on an average of two or more seated blood pressure readings obtained more than one minute apart at two or more occasions.

Normal blood pressure is less than systolic 120 and diastolic 80
Prehypertension is Systolic 120 to 139, Diastolic 80 to 89.
Stage 1 hypertension is systolic 140 to 159, Diastolic 90 to 99.
Stage 2 hypertension is systolic greater than 160 and diastolic greater than 100.

There is a normal variation of blood pressure during the day, highest in the early morning remaining high during working hours and dropping during the night.

A lot of normal activities increase blood pressure as listed below. During meetings by 20/10, work by 16/13, transportation by 14/9, walking by 12/6, dressing by 12/9, talking on the telephone by 10/7, eating by 9/9, and talking by 7/7. Blood pressure is decreased during sleep by 18/7. All forms of exercise increase the blood pressure and heart rate. However the increase is less in physically fit individuals and with exercise training.

Home blood pressure monitoring can be useful to keep a track of blood pressure. For example two measurements in the morning between 7 a.m. and 10 a.m. and two measurements in the evening between 7 p.m. and 10 p.m. for seven consecutive days are recommended. Values from the first day are discarded. Readings from subsequent six days are averaged. If it is less than 125/75 hypertension is not present and drug treatment can be deferred. If the value exceeds 135/85 hypertension is likely to be present.

For values between systolic 125 to 135 and diastolic 76 to 85 ambulatory blood pressure monitoring (ABPM) is recommended. This is a useful means of assessing blood pressure over a 24 hour period. In this method a monitoring device is worn over a 24 hour period which records the blood pressure every hour and generates a computer report. If the 24 hour value is greater than 130/80, treatment is reasonable. Research using ABPM has shown that night time blood pressure levels provide the greatest information regarding cardiovascular risk. ABPM is especially useful in diagnosing white coat hypertension, masked hypertension and resistant (difficult) to control blood pressure.

White coat hypertension

Patients with white coat hypertension have elevated blood pressure in the doctors’ clinic but normal measurements outside the clinic with absence of target organ damage. It is characterised by at least three separate clinic values above 140/90 and at least two sets of measurements below 140/90 obtained outside the clinic. ABPM is the standard for diagnosing white coat hypertension. Drug management of white coat hypertension has not been shown to produce cardiovascular benefit. However patients with white coat hypertension are at higher risk of developing sustained hypertension and should be carefully monitored.

Masked hypertension

This is characterised by a blood pressure which is higher when taken at home than a value of less than 140/90 obtained in the doctor’s clinic. In this situation ABPM should be utilised and a value greater than 130/80 confirms masked hypertension. A number of studies have suggested that cardiovascular risk is increased by masked hypertension.

Resistant hypertension

Resistant hypertension occurs when blood pressure consistently exceeds the blood pressure goal despite taking three antihypertensive drugs. Factors contributing to this are high salt intake, high alcohol intake, sleep apnea, cigarette smoking, obesity and presence of other diseases like diabetes and chronic kidney disease and socioeconomic stress. Several commonly used drugs for example Arthritis medications, corticosteroids, Decongestants like common cold remedies, oral contraceptives, and caffeine can increase blood pressure. 

Essential hypertension

The great majority of hypertension is essential hypertension where there is no apparent cause. It is due to complex interaction of multiple factors including genetic predisposition. 

Secondary hypertension

This is where elevated blood pressure is secondary to other diseases like kidney disease, and endocrine disorders. 

(The writer is a Consultant in Cardiovascular diseases)

Management of hypertension

Drug treatment is recommended when blood pressure remains above 140/90 in patients younger than 80 years of age, and if above 150/90 in those over 80 years. The treatment goal for patients with diabetes and in those with chronic kidney disease is a blood pressure less than 130/80. There is strong evidence that reducing an elevated systolic as well as diastolic blood pressure reduces heart disease related death, myocardial infarction, heart failure and fatal and non fatal stroke. Most guidelines support life style modification and initiation of drug treatment if blood pressure remains above 140/90.

Non drug approaches useful in lowering blood pressure are weight loss if overweight , reduction in salt intake, increase in aerobic physical activity of at least 30 minutes a day three times a week and reduction in alcohol consumption and reduction of socioeconomic stress. Stressful situations can cause sudden increases in blood pressure and chronic stress can contribute to hypertension. Meditation and Yoga maybe helpful in lowering blood pressure.

Although non drug treatment may be useful for mild hypertension the majority of patients require drug treatment. Blood pressure lowering drugs have to be taken for a lifetime to maintain their benefit and a lot of patients are reluctant to take medications for high blood pressure as most of them feel well. One of my patients on being advised to take blood pressure lowering drugs told me that his high blood pressure and high cholesterol are related to work stress and took an early retirement rather than take pills. On checking his blood pressure three months later both his cholesterol and blood pressure had come down! Unfortunately most of us cannot afford to retire prematurely to control our blood pressure and need to take blood pressure lowering medications.

There are five main classes of blood pressure lowering drugs, ACE inhibitors, Angiotensin receptor blockers, Beta blockers, Calcium channel blockers and Diuretics. When used effectively they can lower the blood pressure and reduce target organ damage.

The above classes of drugs are safe, well tolerated and effective when taken under medical supervision. Choosing what drugs are suitable involves a decision-making process taking into account age, presence of other diseases, anticipated side effects and cost and is best done by your doctor. The usual response to a single drug is a reduction of systolic by 12 to 15 and diastolic by 8 to 10. In patients whose goal blood pressure requires a reduction of systolic more than 20 and diastolic more than 10 at least two drugs are required.

In general, a combination of drugs is required for adequate blood pressure control. Once drug treatment is started follow-up visits to the doctor are needed usually in two weeks for checking adequacy of blood pressure control and possible side effects of drugs. Most blood pressure lowering drugs can be taken once a day as their effect lasts 24 hours. I recommend taking all your pills first thing in the morning before breakfast.

There is no urgency to lower elevated blood pressure unless it is very high (greater than 180/110). A sudden lowering of blood pressure can cause dizziness and weakness, due to a sudden reduction in blood flow to the brain. I recommend a gradual lowering of blood pressure to allow the body to get adjusted to the lower level of blood pressure. Start low and go slow. Can blood pressure be too low? Current recommendation is to avoid lowering the diastolic blood pressure less than 70 in those with coronary artery disease.

In summary I recommend that everyone purchase an electronic blood pressure measuring device which is relatively inexpensive and monitor their blood pressure and heart rate. If the blood pressure and or heart rate are elevated, consult your doctor as effective and safe blood pressure lowering drugs and heart rate lowering drugs are available. This is one of the best cost effective purchases you can make and will prolong your life.

Finally in patients whose blood pressure cannot be controlled with drugs or who are intolerant of drugs, catheter based methods which interrupt the sympathetic nerve supply to the kidneys (Radio-frequency ablation of the renal nerves ) will be available in the future.

In conclusion, controlling your blood pressure will preserve the function of your heart, brain and kidneys, and prevent heart disease, strokes and kidney disease. If you already have heart disease or kidney disease or have had a stroke, treating an elevated blood pressure will prevent further progression of your condition. Many of us are taking blood thinners like aspirin, clopidogrel or warfarin to prevent heart attacks and strokes.

These medications increase the risk of cerebral (brain) bleeds and this risk is lower if your blood pressure is in the normal range. Also autopsy studies have shown that 1-5% of adults have undiagnosed cerebral aneurysms and the risk of rupture which could be fatal can be reduced if your blood pressure is under control. I recommend treating an elevated blood pressure to preserve the quality of life and to live longer.

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