Hypertension (High blood pressure): What is it can what can be done to prevent it?

Hypertension is one of the most common forms of chronic disease all over the world. In Singapore, slightly less than 25% of the population aged between 30-69 has been diagnosed with hypertension and about 50% of the population between 60-69 years old have hypertension.

What is it?

Hypertension is more colloquially known as “high blood pressure”. Blood pressure is the pressure of which the blood is pressing on the blood vessels. Normal blood pressure is below 120/80 mmHg. You have hypertension if your blood pressure is perpetually above 140/90 mmHg. There is no cut-off currently for low blood pressure, but low blood pressure (hypotension) is usually diagnosed with the presence of symptoms such as nausea or headache.

Causes of hypertension are still widely unknown, but in some cases, it may be due to kidney diseases, narrowing of certain blood vessels, or hormonal imbalances. The risks of getting hypertension are shown to be higher in people who are obese or are currently suffering from diabetes.

What does the blood pressure value mean?

The first number on the blood pressure monitor is the systolic blood pressure, which measures the amount of pressure on the arteries during the contraction of the heart muscles. The second number on the blood pressure monitor refers to the diastolic blood pressure. It measures the pressure in the arteries in between heartbeats.

The numbers are measured in mmHg, which is formally defined as extra pressure generated by a column of mercury one mm high, and 1 mmHg is converted to approximately 133.3 pascals.

Both values are important in the diagnosis of hypertension and the evaluation of risks of heart diseases. However, in most cases, people usually focus more on the systolic blood pressure.

Why should I care about it?

It can lead to serious complications, such as:

• Coronary heart disease

• Heart failure

• Stroke

• Kidney failure

The risk of suffering these complications increases further due to:

• Smoking

• Diabetes

• Presence of high blood cholesterol

• Obesity (BMI >23kg/m2)

Signs and symptoms:

Hypertension usually does not give rise to any symptoms. However, some may experience the following symptoms occasionally if the condition is severe:

• Headaches

• Giddiness

Sometimes, hypertension is only discovered when severe complications already occur, such as stroke or heart attack.

What can I do to prevent hypertension?

Keep your BMI between 23kg/m2 and 18.5kg/m2. (do note that the values I’m quoting are tailored toward the average Asian body type.):

• Healthy diet:

  • Limit intake of all types of fats, replacing saturated fats (dairy, meat, lard) with unsaturated fats (from plants)

  • Limit cholesterol intake (usually from organ meats, egg yolk, squid, fish roe, shellfish, prawns, and animal fats)

  • Increase fiber intake (can be found in oats, fruits, and vegetables)
    

• Exercise for a minimum of 150 mins per week, each time for a minimum of 10 minutes.
  

• Limit alcohol intake to no more than 2 standard drinks a day. One standard drink is equivalent to ⅔ small can of beer (220 ml), 1 glass of wine (100mL), or 1 nip of spirit (30mL)
  

• Do not smoke.

If you are at high risk of hypertension, you should also monitor your blood pressure regularly. There are many types of home blood pressure monitors available, and your doctor or local pharmacist can help you choose one that is the best for you and teach you how to use it.

As hypertension is also often associated with lipid and glucose metabolism disorders such as diabetes, it would also help to control sugar intake as well, especially if your blood sugar is on the high side. (refer to my earlier post on diabetes)

Common blood pressure medications:

1. Diuretics (Hydrochlorothiazide, frusemide, amiloride, spironolactone) work by reducing the amount of water reabsorbed by the body during the process of concentrating urine. These medications are usually taken in the morning to prevent sleep disruption because of toilet trips in the middle of the night.
   

2. Beta-blockers (atenolol) work by inhibiting the beta receptors in the body, thus reducing heart rate and the amount of pressure experienced by the body’s arteries.
   

3. Calcium channel blockers (amlodipine) work by causing vasodilation (widening of blood vessels), such that blood flow will be less restricted and thus exert less pressure on the walls of blood vessels.
   

4. Angiotensin-converting enzyme inhibitors (Captopril) work by inhibiting enzymes that convert angiotensin I to angiotensin II. As angiotensin II causes blood vessels to become narrower and retains more water within the bloodstream, inhibiting the formation of it can lower blood pressure. A common side effect of this class of medications is coughing, so if it is unbearable and interferes with daily activities, you should visit your healthcare provider to have the medication changed.
   

5. Angiotensin II receptor blockers (Valsartan, Candesartan) have similar effects as that of the angiotensin-converting enzyme inhibitors, just that instead of inhibiting the formation, it inhibits its effects.

Common FAQs regarding medicine use:

1. Are the medications addictive? No, and you have to take your medications as prescribed or your blood pressure will not be controlled.
   

2. My friend/relative suggested I take a herb to help with hypertension. Can I take it together with my anti-hypertensive medications? Before you start on any herbs or complementary medications for hypertension, you should check with your pharmacist to prevent any complications that may be fatal.

Complementary medicines:

Traditional Chinese herbal formulas (TCM) have also been well-known for treating hypertension, and the use has been covered in various scientific journals.

Angelica (Xue Ling) has been used in concoctions in TCM prescriptions for invigorating blood. However, when its use is applied in the context of hypertension, it is known for blocking calcium channels and can achieve the same effect as the calcium channel blockers mentioned above.

TCM can also be used to prevent the onset of serious complications brought about by hypertension. Kidney damage caused by hypertension can be prevented using Jiangyamaijing liquid, which is a concoction containing Herba taxilli, Semen cassiae, Fructus crataegi, Fructus lycii, Fructus schisandrae, Chinensis, Concha ostreae and Flos chrysanthemi.

In addition, the Qingxuanjingya decoction and qingxin capsule may lower blood pressure with mild or moderate degrees of hypertension and they have shown to be able to inhibit the activity of the circulatory renin-angiotensin system, which allows it to have a similar effect as the angiotensin-converting enzyme inhibitors and the angiotensin receptor blockers.

While the above examples have shown to be useful in the treatment of hypertension, and are even backed by some scientific evidence, it is still important to check with your healthcare provider to see if these methods are suitable for you. The use of TCM will affect your treatment options, so it is of utmost importance to discuss its usage with your main healthcare provider.

Hypertension is also frequently associated with high-stress levels. Below is a list of essential oils that potentially is able to lower blood pressure via principles of aromatherapy. (More information can be found here.)

• Bergamot -- May lower heart rate and blood pressure
  

• Cedarwood -- Promote relaxation and temporarily decrease heart rate
  

• Citronella -- Help relieve stress to lower blood pressure
  

• Frankincense -- Reduce stress levels and regulate the heart
  

• Lavender -- Calming properties that may reduce anxiety and heart rate
  

• Rose -- Calming and anti-inflammatory characteristics can relax the body to increase blood circulation and lower high blood pressure
  

• Ylang Ylang -- Has been shown to help decrease levels of cortisol (widely known as the stress hormone) to lower blood pressure

Yoga and tuina are also said to be effective in helping lower blood pressure by reducing stress levels.

In recent years, Ayurvedic medicine has also been explored to help with high blood pressure, based on possible causes. More information can be found here.

References:

Xiong, X., Yang, X., Liu, Y., Zhang, Y., Wang, P., & Wang, J. (2013). Chinese herbal formulas for treating hypertension in traditional Chinese medicine: perspective of modern science. Hypertension Research, 36(7), 570-579. (Accessible here)