Dehydration cognitive processes. Since dehydration decreases the volume

Dehydration and the Body


            Dehydration is a medical condition that is when the body
utilizes more water than it takes in. Dehydration occurs after losing a small
percentage, only 1% of one’s total body weight in fluid loss. This water can be
lost in the form of sweat, exhalation, and urine (Adan, 2012, p. 71).
Dehydration affects the human body in several ways, with the focus of this
paper being the effects of dehydration on the brain, heart, and kidneys, respectively.


            Dehydration can affect the brain in many ways. It can
cause limited water in the brain not allowing it to function properly. This can
cause confusion and even headaches for the patient. Dehydration can alter brain
activity and neurotransmitters that are used for cognitive processes. Since
dehydration decreases the volume of blood in the body, there is less blood flow
to the brain in certain areas. This can affect the blood-brain barrier permeability.
Blood flow may be decreased in the primary somatosensory cortex, motor cortex,
prefrontal cortex, anterior cingulate cortex, and the superior temporal gyrus
(Adan, 2012, p. 71-72). Less blood being circulated to the brain can cause
dizziness (Popkin et al, 2010, p. 445). Dehydration decreases the availability
of glucose in the central nervous system which minimizes the ability to use the
brain at its full capacity. This can affect cognitive skills such as memory and
psychomotor (Adan, 2012, p. 71-72). Severe or chronic dehydration has shown to
cause anxiety, panic attacks, or psychosis (Thomas et al, 2008, p. 296).

            Memory. In
most instances, dehydration has caused a decrease in memory abilities. Whether
the material be presented to the subject in a verbal or numerical way, they
often lacked

the ability to relay the information
back to the observer. It has been shown that memory abilities decrease with an
increase in dehydration state (Adan, 2012, p. 73).

Psychomotor. Psychomotor
abilities can be decreased in the presence of dehydration. Instances that
require the subject to have hand-eye coordination become much harder as the
brain cannot process such tasks with ease. Efficiency and speed of the
movements have been shown to deteriorate the more dehydrated the subject became
(Adan, 2012, p. 73).


            The volume of
blood a person has is dependent on water entering and exiting the body.
Dehydration can decrease blood volume causing the heart to work harder by
pumping faster. When changing position from sitting or lying down to standing
up the body must make the necessary adjustments to blood pressure and heart
rate. When the volume of blood is too low the body cannot make these adjustments,
which can cause dizziness, or in the worst case, fainting (Popkin et al, 2010,
p. 445). Long term dehydration has been shown to cause coronary heart disease,
which is a buildup of plaque in the arteries (Armstrong, 2012, p. S122).

            Blood pressure. Dehydration
is a cause of low blood pressure, also called hypotension. This can cause
nausea or fainting. This is due to the decreased volume of blood which reduces
pressure on the larger veins and arteries (Gonzalez-Alonso, 1998, p. S113-114).

            Heart rate. As
the volume of blood decreases during a state of dehydration, the heart must
work harder to accomplish less results. Because of this the heart rate
increases since there is less blood for the heart to pump. When a person
rehydrates and increases their blood volume the heart rate will return to its
original state (Gonzalez-Alonso, 1998, p. S113-114).  


            Kidneys are
responsible for filtering blood and producing urine. Dehydration causes blood
volume to decrease and urination to act the same. During a state of
dehydration, vasopressin is used to encourage the kidneys to hold onto water
and as a result increase blood pressure. This causes the body to produce more
concentrated urine as a hope to bring more water to the blood increasing the
volume of blood in the body (Bouby et al, 2003, p. S39). If dehydration
persists, there is a risk for chronic kidney disease (Armstrong, 2012, p.

            Urine. When
dehydration occurs, the kidneys extract water from the urine to keep as much
water in the body. This causes urine to be a much darker shade of yellow.
Healthy urine when properly hydrated is clear or light yellow. Vasopressin’s task
is to make urination as less frequent and urine as concentrated as possible (Bouby
et al, 2003, p. S40).

            Blood. When a person
is dehydrated, the kidneys try to take as much water out of the urine as they can
to move to the blood to increase the volume (Bouby et al, 2003, p. S39).


Dehydration has shown to have
major effects on the brain, heart, and kidneys. The body responds in extreme ways
when a person is dehydrated or when dehydration persists, and it becomes chronic.
There are serious health conditions that can be caused by not having enough fluids
in one’s body. Dehydration is a serious matter.