Clinically, it is often encountered that many women suffer from low blood pressure in their youth. It seems that middle-aged people have become hypertensive for a year or two. Individual women find it difficult to accept this. Why does this happen?
This is mainly related to changes in female hormones.
I. Characteristics of female blood pressure
The study found that the prevalence of hypertension in menopausal women was lower than that of men of the same age. The prevalence of hypertension in postmenopausal women increases with age, and blood pressure increases faster than men.
Data from the National Health and Nutrition Examination Survey of the United States from 2009 to 2012 showed that the prevalence of hypertension was higher in males between 20 and 44 years of age than among females (11.2% vs 8.7%). The prevalence of hypertension among females after 65 years of age was higher than that of males. The prevalence of hypertension in the 74-year-old age group was 61.7% for males and 66.7% for females.
According to data from the Canadian Health Survey from 2007 to 2009, the mean systolic and diastolic blood pressures of women aged 20-59 years were lower than those of men of the same age, and the average systolic blood pressure of women after age 60 was 126.9 mmHg higher than that of men 122.4 mmHg.
Data from China’s 2012 survey show that the prevalence of hypertension in women under 45 is generally lower than that in men. The prevalence of men and women in the 45-49 age group is basically the same, but the prevalence of hypertension in women over the age of 50 is gradually increasing. One study found that the ratio of prevalence of hypertension among those over 65 years of age was 47.3% compared to 50.2%. Another study found that the ratio of prevalence of hypertension among people older than 60 years was 50.9% to 51.2%. The results of the two studies are not the same, but the trends are basically the same.
Correspondingly, the prevalence of coronary heart disease in premenopausal women is extremely low, only 7%, while the prevalence of coronary heart disease in men of the same age is as high as 48%. Premenopausal women with coronary heart disease are rare in the clinic, and men with coronary heart disease are common in men of the same age.
II. Estrogen has a great influence on blood pressure
Estrogen, also known as female hormones, is mainly secreted by the ovaries. In addition to promoting the development of women, regulating the physiological cycles and fertility of women, and maintaining the unique posture of women, estrogen also has important effects on the functions of the cardiovascular system, nerves, and skeletal system. The effect on blood pressure is one of the effects of estrogen.
1. Reduce salt sensitivity
The salt sensitivity of hypertension refers to the fact that hypertension is particularly sensitive to salt (sodium chloride). A high-salt diet can increase blood pressure significantly. After strict restrictions on salt intake, blood pressure decreases. This kind of hypertension is also called salt-sensitive hypertension.
Estrogen lowers the incidence of hypertension by lowering body salt sensitivity.
2. Directly dilate blood vessels
There are estrogen receptors on vascular smooth muscle cells. Estrogen acts on this receptor and inhibits the flow of calcium ions into the cell. This is similar to the antihypertensive drugs of calcium antagonists, which directly dilate blood vessels and suppress the occurrence of hypertension.
3. Acts on the renin-angiotensin-aldosterone system (RAAS)
RAAS is one of the most important systems in the regulation of human blood pressure. Continuous overexcitation of RAAS can lead to an increase in blood pressure, while ACEI and SARS are antihypertensive by inhibiting RAAS.
Androgens can activate the RAAS system. In contrast, estrogen can inhibit the activity of the RAAS system, reduce vasoconstriction, and suppress the occurrence of hypertension.
4. Other ways
Estrogen can increase the activity of nitric oxide synthase and inhibit the activity of endothelin. Endothelin has a strong vasoconstriction effect. Estrogen can also promote the production of prostacyclin. Prostacyclin has the effect of relaxing blood vessels.
In summary, the secretion of estrogen after menopause is significantly reduced, the body loses the protection of estrogen and causes the blood pressure to gradually increase, and the incidence of coronary heart disease also increases significantly.
In addition, menopause anxiety causes sympathetic nervous system activation is also one of the causes of hypertension.
III. Selection of hypertension antihypertensive drugs in middle age
The treatment of hypertension in middle-aged and elderly women can choose different antihypertensive drugs based on the mechanism of hypertension mentioned above. For example, diuretics may be used for salt-sensitive hypertension; β-blockers may be selected for anxiety-induced hypertension; calcium antagonists, prestige antihypertensives, and satans antihypertensives may be selected for all patients.