Vasodilator Definition and Most Potent Vasodilators: CO2 and NO
Vasodilator (definition) is a factor that causes an increase in the diameter of blood vessels.
This mainly relates to dilation of small arteries and arterioles since they
create the main resistance to the systemic blood flow in the human body (about
70%). A vasodilator can be:
1) a chemical substance such as from food (CO2 from carbohydrates, fats, and NO derived from arginine)
2) or various stimuli, such as reactive hyperemia (in skin and muscles),
exercise hyperemia (muscle), whole body heating (skin) and mental stress
Since over 90% of people breathe much more than the medical norm (see the
Homepage for clinical studies), the main problem with vasodilators relate to
The most common application of
vasodilators is to reduce blood pressure in
people with hypertension and also treat conditions with poor circulation, such
as chilblains and Raynaud's syndrome (poor circulation in hands and feet).
Insufficient and worsening perfusion of vital organs is a clinical feature in
progressing cancer, diabetes, arthritis, hypothyroidism, CFS, and many other
The blood vessels are expanded either by relaxing the smooth muscles of the
vessel walls (as occurs with CO2, nitric oxide, nitrates and calcium antagonists) or by changing nerve signals
that control the tone of the blood vessels (as occurs with alpha blockers).
CO2 and NO (nitric oxide): most potent natural vasodilators (from food)
"... Carbon dioxide, a most potent cerebral vasodilator, ..."
Djurberg HG, Tjan GT, Al Moutaery KR, Enhanced catheter propagation with
hypercapnia during superselective cerebral cauterization, Neuroradiology, 1998 Jul; 40(7): 466-8.
In the right
conditions, the human body can take care of normal blood flow to all
organs and tissues due to the two most potent vasodilators naturally present in the
blood and other cells due to food sources. These
natural vasodilators are CO2 (carbon dioxide) and
NO (nitric oxide).
Carbohydrates and fats are naturally present in food sources and contain carbon
atoms that are oxidized to CO2. Nitric oxide is produced in various parts of the
human body from arginine, an amino acid present in various food sources,
especially meat, fish, and nuts. The action of nitroglycerine and many other drugs are based on
release of nitric oxide. Since sinuses are important sources of nasal NO, nose
breathing and the normal unconscious breathing pattern (relatively sharp, but
small and short inhalations with long and slow exhalations) are crucial for
the utilization of nasal NO.
Mouth breathing (including during physical exercise) prevents absorption of nasal NO
and also reduces arterial CO2 levels causing problems with most important
vasodilators. Carbon dioxide losses occur due to hyperventilation
which is very common in the sick and even "normal" modern subjects at
rest (see links to medical studies below).
This YouTube video "Vasodilator
and vasodilation" explains effects of the most potent vasodilator, carbon
dioxide, on perfusion.
Physical activity and sports also have powerful vasodilating effects that last for many hours after a good workout. Decades ago, in the 1980s, one clinical study discovered that there is a certain duration of daily physical exercise that causes permanent dilation of blood vessels, with reduction of reasting pulse, and other positive effects. This study became famous among top athletes due to its great practical value. You can find out the exact minimum duration of daily physical exercise (to cause the lasting vasodilating effect) right below here as your bonus content.
References: Vasodilator and Most
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