I. Why Does Our Blood Pressure "Fluctuate Wildly"?

First, we need to understand that blood pressure is not a constant value. Just like the tides, it fluctuates regularly throughout the day. Think of blood pressure as the water pressure in a pipe: the heart is the water pump, and the blood vessels are the pipes. Naturally, the level of water pressure (blood pressure) is affected by various factors.

◆ Normal Physiological Fluctuations

Circadian Rhythm: Generally, a person’s blood pressure rises rapidly after waking up in the morning, peaks between 8–10 a.m., then gradually decreases. It reaches a small secondary peak between 4–6 p.m., followed by a slow decline, and hits its lowest point between midnight and 2–3 a.m. This is known as the "dipper pattern" of blood pressure.
Emotional Impact: When you feel nervous, excited, anxious, or angry, your body releases hormones like adrenaline. This speeds up your heartbeat, constricts blood vessels, and causes your blood pressure to spike suddenly.
Physical Activity: During exercise, the heart needs to pump more blood to meet the needs of the muscles, so blood pressure naturally rises. Conversely, during rest and sleep, blood pressure decreases accordingly.
Other Factors: Behaviors such as smoking, drinking alcohol, consuming coffee, or holding in urine can also cause temporary increases in blood pressure.

These are all normal physiological responses, as the body adapts to changes in the internal and external environment. However, if your blood pressure remains "persistently high" or "continuously low" over the long term, you need to be alert!

II. The "Silent Killer" – Dangers of High Blood Pressure

High blood pressure (usually defined as a systolic blood pressure ≥ 140 mmHg and/or a diastolic blood pressure ≥ 90 mmHg without the use of antihypertensive drugs) is called the "silent killer" because it may have no obvious symptoms in the early stages, yet it quietly damages our vital organs.

Key Dangers

Overburdened Heart: Long-term high blood pressure increases the resistance the heart faces when pumping blood, forcing the heart muscle to thicken. This can eventually lead to heart failure. At the same time, it accelerates atherosclerosis, triggering coronary heart disease and myocardial infarction.
High-Risk Brain: High blood pressure is the most significant risk factor for stroke. It can cause cerebral blood vessels to rupture and bleed (cerebral hemorrhage) or lead to blood clots that block cerebral blood vessels (cerebral infarction).
Stressed Kidneys: The kidneys are like "filters" composed of countless tiny blood vessels. Long-term high blood pressure damages these vessels, leading to decreased kidney function and, in severe cases, uremia.
Threatened Retina: High blood pressure causes hardening and bleeding of the retinal arteries, resulting in blurred vision, vision loss, or even blindness.

Summary: The harm of high blood pressure is systemic and devastating. Never let your guard down just because you "feel nothing"!

III. "Signs of Weakness" – Low Blood Pressure Should Not Be Ignored

Many people think low blood pressure is harmless, and some even consider it a sign of "longevity and good health." This is incorrect. Low blood pressure (usually defined as a systolic blood pressure < 90 mmHg and/or a diastolic blood pressure < 60 mmHg) can also cause health problems.

Key Dangers

Insufficient Blood Supply to the Brain: This leads to dizziness, fatigue, low spirits, and poor concentration. When your body position changes suddenly (e.g., standing up quickly after squatting), you may experience blackouts, dizziness, or even fainting. This is medically called "orthostatic hypotension" and can easily lead to accidental injuries like falls.
Impaired Organ Function: Long-term, severe low blood pressure reduces blood perfusion to tissues and organs throughout the body, affecting the supply of oxygen and nutrients. This may cause problems such as decreased hearing and vision, and memory loss.
Increased Cardiovascular Risk: For patients with existing cardiovascular diseases, excessively low blood pressure may cause ischemia of the heart muscle or brain tissue, raising the risk of myocardial infarction and cerebral infarction.

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