When is blood pressure highest?

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By Dr. Victor Dumaguing

To Your Health

Friday, March 28, 2014

THE human body is an excellent piece of machine... forgive me for the word, but the word was chosen to emphasize the fact that the human body has God as its architect and engineer. Its parts differ, in structure as well as in their function, but each part does its best performance to bring about a harmonious well-coordinated totality of wholeness of a human being. The normalcy of the human body is brought about by a series of dynamic changes in the activity of its parts, so that if one veers away from the normal pattern, another part of the body will compensate by doing the corrective measure to bring that wayward part back to its normal path again.

The author asks our readers and friends for their kind indulgence in the rather lengthy preface to the main issue. The point is, within a 24-hour period, there are numerous fluctuations in the functions of the different parts of the body, and this has patterns; diurnal means daily, nocturnal if the phenomenon occurs only at night, explosive if there are spurts of increase in either hormone or enzyme or continuous if there is a relatively stable, sustained level of a substance in the blood.

Waking hours is the most dangerous time for a patient with hypertension or elevated blood pressure. Many people or shall I say, almost all people find this statement hard to believe. For one, they argue that, during sleep the person is rested, and with his eyes closed and his mind temporarily shut off from the realities and inanities of daily life, the blood pressure should not rise. True enough, any reasonable person would see the logic in such argument and would think twice before believing it. However, many times over, research and actual studies involving actual patients have indeed shown that humans, whatever race, gender, religious persuasion and what you have, shown a common pattern in the rise and fall of blood pressure.


Blood pressure starts to rise at 3 a.m. early dawn and reaches its peak 8-10 a.m. in the morning, then goes down a bit and has another rise a 3-5 p.m. The rise is not as high as the morning increase- then falls gently unto the night and rise again at 3am the next day. For those who argue that there is no stress during sleep, experts say that it is not the stress hormone adrenaline or epinephrine that is at play here.

Adrenaline is known as the Fight or Flight hormone, meaning whenever a person is in danger, it p[rimes and prepares that person by increasing heart rate, supply blood to the muscles, dilate his pupils to see either the enemy or look for a way out or escape route, in case he cannoty subdue the opponent. Obviously, sleep does not provide these scenarios. Endocrinologists instead have known that during early morning hours, there is a significant rise in hormones coming from the adrenal cortex- particularly cortisol and aldosterone. Sodium is a big no-no for hypertensive people that's why we lift their salt intake.

Aldosterone favors the reabsorption of sodium from the kidneys back to the blood and the increase in sodium could expand blood volume, increasiong cardiac output to more than the normal 5 liters, thus contributing to a rise in blood pressure. Although cortisol is primarily involved in sugar, fat and protein metabolism, it also has slight effects on sodium thus participate in rise in blood pressure.

This fact has been a guide to doctors, depending on how high your blood pressure, what medicines to give you, solo or in combination, and the more crucial issue, WHEN or WHAT time of the day or night, to take your BP medicine. Please follow their advise!

Published in the Sun.Star Baguio newspaper on March 29, 2014.


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