Water
It is said that water is the ideal drink for the human being, and that drinking
water is good for one’s health. The reasons why this would be the case, however,
are rarely stated. As a consequence, water, as a drink, is often neglected as a
factor in health.
THE BODY’S WATER CONTENT
Although the body is constructed of both liquid and solid materials, fluids are
present in much greater quantity than solids. Physiology teaches us that water is
actually the most important constituent of the body, accounting for 70 percent of
the human body’s composition.
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TABLE 1.1
THE BODY’S WATER CONTENT BASED ON AGE
Age Water Content (%)
4-month fetus 93
7-month fetus 85
newborn 80
child 75
Adult 70
Elderly person 60.
High and Low Blood Pressure
The body’s blood volume is not enough to completely fill the entire set of
arteries, veins, and capillaries. Regions of the body in which requirements for
blood are not very high will therefore supply some of it to regions whose needs
are greater.
For example, when we eat, the digestive tract has a greater need to be well
irrigated than the muscles of the legs, which are idle at the time. The blood
vessels of the legs therefore contract and expel some of their blood toward the
vessels of the digestive tract. These vessels then dilate to take in the extra blood
they need. The vasoconstricting and vasodilating capabilities of the vessels allow
the body to make adjustments that are crucial for its proper functioning.
However, these capabilities can be used in exaggerated ways, which can result
in health problems. Among other things, when the body deals with too little
blood volume caused by chronic dehydration, the blood vessels sharply contract.
This ensures that the volume of blood available—already limited in normal
circumstances, but now even more so because of dehydration—sufficiently fills
the vessels without leaving free spaces where pockets of gas could form.
But this defensive vasoconstriction can become permanent if the body is
suffering from a chronic liquid deficiency, and the result is chronic high blood
pressure. The increase of tension in the walls of the veins is exacerbated by a rise
in blood viscosity. The body is compelled to raise the pressure with which it
pushes the blood through the veins to compensate for the slowdown in
circulation caused by the increased thickness of the blood.
While dehydration can in some cases be responsible for high blood pressure, it
can also encourage the opposite condition, low blood pressure. If hypertension is
characteristic of people whose vessels have good tone and contract easily, low
blood pressure afflicts those whose vascoconstricting capabilities are weak.
Their blood pressure is lower than average because their blood is circulating
though vessels that are not tight and narrow.
When a person with low blood pressure becomes dehydrated, the blood
volume shrinks, but the vessels cannot reduce their diameter sufficiently to
compensate for the lower blood volume. The blood is thus circulating in slack,
poorly filled vessels, and the pressure falls even lower.
WATER
Drinking water is never pure in the chemical meaning of the word. Water that is
composed exclusively of two hydrogen atoms and one oxygen atom (H2O) can
be created only in the laboratory. Generally, water contains mineral salts that it
has captured while traveling underground. Drinking water is not a uniform
substance that always has the same composition wherever it is found. To the
contrary, its mineral content and consequently its character (its taste, its odor)
vary according to its provenance.
There are many different kinds of water, but they can be separated into four
major groups.
1. Odorless, tasteless waters. These are the purest waters, whose mineral
content is quite low. Evian water, for example, is the benchmark used by
professionals in the bottled water industry.
2. Odorless waters that have taste. These are the classic spring waters.
Minerals like calcium, magnesium, or sodium confer a slight flavor. The
extreme example is Vichy Celestin water, which has a very pronounced
salty flavor because of its high sodium content.
3. Waters with odor and no taste. These are also classic spring waters. In
contrast to the waters of the second group, they contain minerals like sulfur
that give them a strong and characteristic odor. These waters are not sold
commercially but are available directly from the spring at the thermal spa.
4. Waters that have taste and odor. This is tap water; the presence of
chlorine gives it both odor and taste.
Keep hydrated in this summer









