Everybody has heard that hypertension (high blood pressure) is one of the main causes of stroke and cardiovascular disease, which, in turn, can lead to death. But not so many people know what causes hypertension.
As blood flows through the body, it pushes against the walls of the arteries. This force in the arteries is what is called “blood pressure.” Essentially, blood pressure represents the relationship between the volume of blood and the area of a cross-section of the artery at any given point. Blood pressure measurements include systolic pressure, which is read when the heart is constricted, and diastolic pressure, which is read when the heart is dilated. Normal systolic blood pressure is less than 130 mmHg and normal diastolic blood pressure is less than 90 mmHg.
If obesity and/or hyperlipidemia (high cholesterol or triglyceride fat levels in the blood) cause the wall of the artery to become narrow and atherosclelotic (hardened), blood pressure becomes high. Blood pressure also rises when there is an increase in blood volume caused by excess water retention in the body. For example, high salt intake increases blood volume and thereby leads to hypertension.
The two most common causes of hypertension are arteriosclerosis and high salt intake. Therefore, you should try to avoid gaining excess weight and consuming too much salt (or soy sauce).
There are, however, other key factors that control blood pressure — among them, hormones. There are several hormones that affect blood pressure. One is adrenaline. This hormone is secreted by sympathetic nerves whenever you get nervous, even if you are not hypertensive. However, if this hormone is overproduced even when you are not nervous, then you develop hypertension.
Here is a case that I encountered in our endocrine clinic. A 30-year-old man was referred to us because he suffered from frequent headaches accompanied by sweating, palpitation and hypertension, none of which responded favorably to medication. His systolic blood pressure was 200 mmHg and diastolic pressure was 100 mmHg. He was found to have a tumor in his adrenal gland, which was overproducing adrenaline. His hypertension was treated only with the removal of the tumor.
Thyroid hormone also affects blood pressure. A 17-year-old girl came in complaining of pounding headaches and palpitation. Her eyes protruded and her hands had tremor. Her systolic blood pressure was 180 mmHg and diastolic pressure was 76 mmHg. She was found to have an enlarged thyroid gland and an elevated thyroid hormone level. Her high blood pressure improved not with the use of blood pressure medication, but with lowered thyroid hormone level.
Cortisol, which is a hormone normally produced in the adrenal gland when we are exposed to stress, also increases blood pressure. Therefore when you are under stress, your blood pressure temporarily become higher. I had a 60-year-old patient who arrived in the ER unconscious with high blood pressure and high blood-sugar levels. She was found to have a tumor that produces cortisol.
There are other hormones that increase blood pressure, such as growth hormone, rennin and aldosterone.
The causes of hypertension in elderly people are usually arteriosclerosis or high salt intake and not these hormone problems. But when you are young and have high blood pressure, you may have some hormonal abnormality. To young(er) readers experiencing difficulty in controlling high blood pressure, I would advise you to visit an endocrinologist to find a possibly hidden cause of your hypertension.