Hello, welcome to the "Hypertension Medical Course." I am Jessica.
When it comes to hypertension, the most fundamental question is—Is
hypertension a disease?
At first glance, this hardly seems like a question. Many people believe
that hypertension is obviously a disease! After all, hypertension is so
harmful, antihypertensive drugs are abundant, and as soon as someone is
diagnosed with hypertension, doctors will always say, "Take your
medication on time." Treating with medication—hypertension must be a
disease.
And it’s not just you; many doctors think so too. Even the most
rigorous medical textbooks will tell you—if blood pressure remains
stably elevated beyond a certain range, it is a definite disease called
hypertension.
However, in my view, thinking this way oversimplifies hypertension.
Whether it’s the causes, diagnostic criteria, treatment approaches, or
attitudes toward it, hypertension is different from conventional
diseases. Simply applying the disease model to hypertension affects
our understanding and, consequently, our prevention and treatment
strategies.
Why do I say this? Let’s take a closer look.
The Standards Are Artificially Defined
First, if we regard something as a disease, it should naturally have
clear diagnostic criteria. Just like COVID-19—a nucleic acid test will
tell you if you’re infected; the standard is very clear.
Following this logic, we naturally ask: What are the diagnostic
criteria for hypertension? In other words, at what blood pressure level
is it considered hypertension? Is it 140/90 mmHg or 130/80 mmHg?
You might think this is simple. Find a critical threshold—above it,
damage occurs, so it’s hypertension; below it, there’s no harm, so it’s
not hypertension. But in reality, we cannot pinpoint this so-called
threshold.
Before 1980, the diagnostic standard for hypertension in China and the
World Health Organization was 160/95 mmHg. But after 1991, global
medical guidelines mostly lowered the standard to 140/90 mmHg. In
recent years, as medical evidence accumulates, experts have found that
even 140/90 mmHg may be too high; perhaps 130/80 mmHg is better, or
even 120/80 mmHg is preferable to 130/80 mmHg.
The most famous is the SPRINT trial in the United States. Researchers
lowered the systolic blood pressure of hypertensive patients to below
120 mmHg and found that, compared to the traditional 140 mmHg target,
these patients had significantly lower mortality rates from coronary
heart disease and stroke.
Similar studies have proliferated in recent years. As a result, the
latest hypertension guidelines show global divergence in diagnostic
standards. Currently, the U.S. standard is 130/80 mmHg, while Europe
and China still use 140/90 mmHg.
The reason standards keep changing, besides advancing research, is the
undeniable influence of pharmaceutical interests. In the West, many
trials are driven by pharmaceutical companies, which hope to lower the
guideline numbers so more people need antihypertensive drugs,
increasing their profits.
So, as you can see, the diagnostic criteria for hypertension differ
from conventional diseases. They are entirely artificial, constantly
changing, and may vary between countries.
More Like an Inevitable Part of Aging
Moreover, looking at the epidemiology of hypertension, it’s hard to
define it strictly as a disease.
A global survey of 90 countries shows: among people aged 40–49, the
prevalence of hypertension is about 31%; for ages 50–59, it’s around
45%; for ages 60–69, it exceeds 60%. U.S. data show that by age 75, the
prevalence reaches 90%; for those over 85, it’s nearly 100%—it’s hard
to find someone without hypertension.
What does this mean? As age increases, the prevalence of hypertension
rises so much that, if you live long enough, hypertension is almost
inevitable.
Is there any disease that everyone gets at a certain age? If everyone
gets it, can it still be called a disease?
From this perspective, hypertension is less like a disease and more
like an inevitable consequence of aging.
A Non-Steady State Environment
Finally, let’s talk about the harm caused by hypertension.
Diseases usually have clear and direct harm. Take COVID-19 again—the
virus attacks the lungs, causing respiratory distress and even organ
failure in severe cases.
Hypertension is different. For our bodies, elevated blood pressure is
nothing new; our blood pressure rises many times a day, but our bodies
handle it easily. However, while transient hypertension isn’t directly
harmful, chronically elevated blood pressure increases the risk of
various complications.
First, it damages blood vessels. Persistently high blood pressure
exerts continuous physical stress on vessel walls.
Specifically, when vessel walls sense sustained pressure, they respond
by thickening to prevent rupture—a process called "vascular
remodeling."
In theory, vascular remodeling protects the vessels, but every benefit
comes with a cost. Thicker vessels may be stronger but also become
stiff and less responsive, impairing blood pressure regulation.
Moreover, the thickening grows inward, narrowing the vessel lumen. All
this means remodeled vessels lose elasticity, have smaller diameters,
and blood pressure rises further.
Additionally, sustained hypertension indirectly damages organs
supplied by these vessels.
Here’s how:
Chronic high pressure injures the endothelial cells lining the vessel
walls. The immune system detects this injury and responds, much like it
would to a skin wound—by sending immune factors to help. But instead of
repairing the vessel, these immune factors worsen inflammation.
Over time, this greatly increases the risk of plaque formation, leading
to vessel narrowing. If this happens in the heart, it causes coronary
artery disease; in the brain, stroke; in the kidneys, renal impairment;
in the eyes, retinal hemorrhage and vision loss.
So, in a sense, hypertension is more a risk factor for these diseases
than a disease itself. If the cyclical fluctuation of blood pressure
maintains life’s steady state, then chronic hypertension gradually
drags the body into a non-steady state environment—short-term effects
may be minor, but over time, collapse is possible.
Defining Hypertension Thresholds
Understanding all this, if we don’t simply regard hypertension as a
disease, we can better appreciate the various medical approaches to its
prevention, reversal, and treatment.
For example, since hypertension isn’t a conventional disease but an
inevitable part of aging, we should determine its diagnostic threshold
based on the overall pattern of blood pressure changes throughout
life—and this threshold should be individualized.
First, age is the most important factor affecting the threshold.
As mentioned, the older you are, the higher the risk of hypertension,
so age itself is a risk factor. When you’re young, blood pressure
should be low; as you age, the criteria can be relaxed.
For example, ages 25–35, ideal blood pressure is 115/75 mmHg—to leave
room for age-related increases.
Before 40, try not to exceed 120/80 mmHg.
Ages 40–50, blood pressure typically rises, but should stay around
125/80 mmHg.
Before 55, below 135/85 mmHg is acceptable.
By 65, maintaining 140/90 mmHg is good. By then, cerebral vessels are
likely narrowed and hardened, so too low a pressure may compromise
brain perfusion; conversely, slightly higher pressure may not cause
significant organ damage within a limited lifespan.
Second, the threshold should not ignore baseline blood pressure.
Baseline blood pressure is your average level after reaching adulthood.
Some people naturally have low blood pressure, maybe 90/60 mmHg; others
are closer to the average, around 120/80 mmHg. This is your baseline.
A slightly higher or lower baseline isn’t a problem—it’s your vascular
steady state. But if you deviate too far from this steady state, damage
is inevitable. Generally, if systolic pressure rises more than 20 mmHg
or diastolic more than 10 mmHg above baseline, that’s an important
indicator for hypertension.
Finally, the threshold should be the minimum needed to meet your
body’s perfusion needs.
As mentioned, lower blood pressure is better when young, but it must be
sufficient to support daily activities. Excessively lowering the
standard may leave you fatigued and increase unnecessary healthcare
costs.
Whenever I see the ever-lowering blood pressure thresholds, I recall my
teacher Professor Han Qide’s words: “People’s dissatisfaction with
modern medicine isn’t because it’s ineffective, but because it doesn’t
know when to stop.”
Preview of the Next Lesson
Having discussed the essence of hypertension, next time we’ll enter the
real world and see how doctors diagnose hypertension in actual
patients.
I am Jessica. See you tomorrow.
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