Electrolytes
Electrolytes are soluble inorganic
compounds whose ions will conduct an electrical current in water
- The two most common electrolytes lost by
athletes through perspiration are sodium (Na+) and potassium
(K+)
- In 90 degree weather young adult tennis players
have a sweat concentration of sodium a little above 20 mmol per
liter, and sweat potassium losses of approximately 5 mmol per
liter.
- Electrolyte balance is important for two
reasons; one, a loss or gain in electrolytes can cause a loss
or gain in water and two, the concentrations of various electrolytes
affect a variety of cell functions.
- Changes in body fluid concentrations can
seriously impair the body's ability to function properly.
Sodium
- Most commonly found ion in the extracellular
fluid, the fluid in the body which is not inside cells.
- Since it is so common, changes in sodium's
ion concentration have immense effects on the osmotic movement
of water from one fluid compartment to another.
- Aldosterone, a hormone that stimulates water
and sodium conservation at the kidneys, helps maintain a steady
sodium ion concentration.
- In order to keep the sodium ion concentration
constant when there is an increase in sodium ion there is a corresponding
increase of water and vice versa.
Potassium
- Potassium is the most commonly found ion
in intracellular fluid, the fluid in the body which is inside
cells.
- A declining potassium ion levels can cause
general muscular paralysis, and an increased potassium concentration
can cause weak and irregular heart beats.
- Potassium ion secretion is also controlled
by aldosterone, but in an opposite manner.
- When there is an decrease in sodium, potassium
gets excreted and sodium gets reabsorbed.
- In order to transmit nerve impulses it is
necessary to have normal concentrations of both sodium and potassium
ions.
- Critical that athletes continually replenish
electrolytes lost through perspiration.