What
is dehydration?
Dehydration
is the excessive loss of water from the body,
as from illness or fluid deprivation. Any person
who exercises on a regular basis is susceptible
to the effects of even mild fluid loss.
The
value of the body's most important nutrient, water,
cannot be underestimated. Exercise produces body
heat, and too much body heat reduces exercise
capacity. As the core body temperature rises,
the blood flow to the skin increases, and the
body attempts to cool itself by sweating.
During
exercise the body temperature rises as high as
105 degrees Fahrenheit and the muscle temperature
can rise as high as 108 degrees Fahrenheit. These
temperatures make exercise difficult because the
body and muscles are competing for blood supply.
As the body temperature rises, oxygen becomes
more of a commodity due to increased circulatory
demands. Oxygen is needed to help with the cooling
process, which reduces the amount of oxygen available
for vital organs. This can lead to severe health
risks as well as a drop in athletic performance.
When
you start exercising, as much as two percent of
the body water is lost. Although this amount is
considered a "normal" range for humans,
it is not an optimum level for athletic performance.
Below is a table that summarizes the effects of
minimal fluid loss during exercise.
PHYSICAL
SYMPTOMS AND EFFECTS OF DEHYDRATION
BODY
WATER LOSS SYMPTOMS
1%
Few symptoms or signs of any thirst present; however
there is a marked reduction in VO2max.
2% Beginning to feel thirsty; loss of endurance
capacity and appetite.
3% Dry mouth; performance impaired.
4% Increased effort for exercise, impatience,
apathy, vague discomfort, loss of appetite.
5% Difficulty concentrating, increased pulse and
breathing, slowing of pace.
6-7% Further impairment of temperature regulation,
higher pulse and breathing, flushed skin, sleepiness,
tingling, stumbling, headache.
8-9% Dizziness, labored breathing, mental confusion,
further weakness.
10% Muscle spasms, loss of balance, swelling of
tongue.
11% Heat Exhaustion, delirium, stroke, difficulty
swallowing; death can occur.
Dehydration can cause any or all of the following
problems:
* Increased
heart rate per minute
* Increased lactic acid in muscles
* Increased body temperature
* Decreased strength
* Any of the following medical conditions: heat
cramping, heat exhaustion & heat stroke
The
best way to avoid fluid loss is often the simplest.
Drink plenty of fluids. Water is sufficient to
replenish the fluids that are lost during exercise.
However, water cannot replace the minerals that
are lost during exercise-induced sweating. Sweating
releases potassium, sodium and calcium, which
are vital for survival. These minerals, also known
as electrolytes, are not found in water. It is
advisable to consume a supplement, which contains
these added minerals, before any strenuous exercise.
One
supplement that contains these electrolytes is
a "sports drink."
Although
sports drinks contain a combination of vitamins
and minerals, they also contain simple and complex
carbohydrates, predominantly simple sugars, which
provide the athlete with an added amount of glucose.
This glucose, which is converted by the body into
fuel, can later be used to power the working muscles.
The carbohydrates that are found in sports drinks
are designed to help in performance, and do not
play a direct role in hydration. The added nutrients,
potassium, sodium, and calcium, along with the
water content, is the determining factor in hydration.
Exercise
scientists, along with savvy marketers, have designed
the newest product to conquer dehydration - fitness
water. This new product has taken regular water
and added minerals and vitamins including those
vital electrolytes, potassium, sodium, and calcium.
This new product is targeting the fitness enthusiasts
who want to protect against dehydration, but who
are looking to keep their calorie count and sugar
intake to a minimum.
Caffeinated
drinks should be avoided wherever possible. Caffeinated
products increase urine output, which raises the
amount of fluid loss. This fluid loss is exactly
what you are trying to avoid. Many people drink
caffeinated drinks before exercise to obtain extra
energy. A suggestion to those who need the extra
energy: avoid the caffeine and take a vitamin
B tablet instead. The vitamin B tablet will give
the extra energy desired, without the increased
fluid loss.
Another
product to avoid in relation to hydration is alcohol.
Alcohol,
like caffeine, increases urine output, which increases
fluid loss. Although most people will not consume
alcohol just before exercising, it should be noted
that a few drinks the night before a morning workout
could have a large effect on hydration levels.
If planning on exercising the morning after consuming
alcohol, drink a lot of fluids, including the
necessary electrolytes.
Taking
in the required electrolytes, as well as satisfactory
levels of fluids, will determine hydration level.
It is vital to monitor the body and to continually
take in fluids. By the time thirst sets in, the
body has already lost at least two percent of
its fluid, and dehydration occurs. At any chance
possible before and during exercise consume fluids
to avoid the harmful consequences of dehydration.
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Mark
Kovacs has a degree in Exercise Science from Auburn
University and is a certified Health/Fitness Instructor
through the American College of Sports Medicine.
Mark won the 2007 NCAA Mens Tennis Doubles Championship
and has worked as a personal trainer and strength
and speed consultant for the past three years.
Mark can be contacted about training and nutrition
at mark@healthfitness.com.au
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