1. Hypotension Is Very Common in People With Hypertension
Many people assume that people with hypertension only have to worry about "high" readings, but in clinical practice, various forms of low blood pressure in hypertensive patients are common and often more difficult to manage.
1.1 Orthostatic (Postural) Hypotension
Orthostatic hypotension is the most common form. Many people have experienced it: after squatting or lying down for a long time, standing up suddenly leads to dizziness, blackout, or ringing in the ears—this is a mild form of orthostatic hypotension.
When the body moves quickly from lying or sitting to standing, gravity causes blood to pool in the legs and abdomen, reducing venous return to the heart and causing a rapid drop in blood pressure. Normally, the body compensates by increasing heart rate and constricting blood vessels, but if this mechanism is impaired, obvious symptoms appear.
Clinically, orthostatic hypotension is usually defined as a drop in systolic blood pressure of ≥20 mmHg or diastolic pressure of ≥10 mmHg within three minutes of standing or sitting up. Some studies also use a transient drop of ≥40 mmHg systolic and/or ≥20 mmHg diastolic within 15 seconds of standing as evidence of disordered blood pressure regulation.
It is particularly common in older adults. Studies suggest that about 20% of community-dwelling elderly people and 20–31% of those in long-term care institutions have orthostatic hypotension. In some surveys of older women in the UK, the prevalence reaches 28%, and continuous blood pressure monitoring reveals even higher rates.
For this reason, guidelines in several countries recommend orthostatic blood pressure testing in older adults who have fallen, those with hypertension symptoms, diabetes, or age over 80, rather than relying only on seated or supine readings.
Many cases are asymptomatic, so without active screening in high-risk groups, orthostatic hypotension is easily missed.
1.2 Postprandial Hypotension
Postprandial hypotension is even more insidious yet just as common. As its name suggests, it occurs after meals, especially after high-carbohydrate meals such as rice, noodles, or sweets.
After eating, large amounts of blood are redirected to the gastrointestinal tract to support digestion and absorption. At the same time, gut hormones such as vasoactive intestinal peptide cause splanchnic vasodilation and a fall in systemic vascular resistance. Together, these changes lower blood pressure.
Diagnostic criteria are straightforward: a fall in systolic pressure of ≥20 mmHg within two hours after a meal compared with pre-meal values, or a drop from ≥100 mmHg before the meal to <90 mmHg afterward.
Postprandial hypotension is a major cause of dizziness, syncope, and falls in older adults. Its prevalence is around 24–36% among community-dwelling elderly and can reach 70% in institutionalized patients, making it both common and dangerous.
2. Why Hypotension Can Be More Dangerous Than Hypertension in These Patients
We often worry about the damage that high blood pressure causes to vessels and the heart, but for people already diagnosed with hypertension, low blood pressure can produce more immediate and dramatic harm, mainly in three ways.
(1) Markedly Reduced Quality of Life. Pronounced orthostatic hypotension causes dizziness, blurred vision, blackout, and fatigue—especially when getting out of bed in the morning or standing after sitting for a long time. These symptoms seriously disrupt daily life and increase the risk of falls, particularly in older adults.
(2) Serious Complications and Even Life-Threatening Events. Severe orthostatic or postprandial hypotension can lead to sudden falls, fractures, and prolonged bed rest. In older patients, immobilization increases the risk of pneumonia, venous thrombosis, pulmonary embolism, and even intracranial bleeding—all of which can be fatal.
In short, hypotension in people with hypertension is never a "minor issue". Ignoring it can carry a very high price.
(3) Possible Long-Term Cognitive Impairment. Studies suggest that chronic low blood pressure in older adults may increase the risk of cognitive decline, likely by reducing cerebral perfusion over time and gradually damaging brain function, leading to poorer memory and slower thinking.
For older patients with hypertension, the belief that "the lower the blood pressure, the better" is dangerous. Reaching reasonable targets is important, but over-aggressive treatment that produces hypotension can do more harm than good.
3. Many Forms of Hypotension in Hypertensive Patients
Beyond the common orthostatic and postprandial forms, hypotension in people with hypertension appears in many ways. Clinically, it is often divided into two broad categories: disease-related hypotension and treatment-related hypotension caused by medications.
In future articles, we will look separately at these two categories, their typical patterns, and how patients can prevent and manage low blood pressure without falling into the trap of excessive blood pressure reduction.
In this Year of the Horse, may everyone take blood pressure management seriously—not only controlling hypertension, but also remaining alert to the hidden risks of hypotension. Health is never about "lowering numbers at all costs", but about finding the right balance for your own body.