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The osmolality of the various body uids

Substances aect osmolalityGlucoseProteinSeveral electrolytes, most notably sodium

Feedback mechanism for control of body water(dehydration

!smorece"tors in the hy"othalamus aresensitive to

chan#es in osmotic "ressureThese cells react to the more concentratedbody

uids by stimulatin# the release of a hormonefrom

the "ituitary #land, $%&$ntidiuretic hormone travels by blood to thekidneys

and directs them to reabsorb more water'rinary out"ut of water is diminished

Feedback device for the control of body wat

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$cids, bases, and salts are commonelectrolytes The maor electrolytes in the body uids

Sodium Potassium )hloride *icarbonate Sulfate +a#nesium )alcium

lectrolyte functions in the body Generate electrical current, such as in anerve

im"ulses $ctivate en-ymes to control a variety of

metabolicactivities in the cell

lectrolytes

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!ne of the "rinci"le "ositive ions inthe body uids

stimated minimum re.uirements foradults, /00

milli#rams %1 is 234 #rams %ietary sources

Found in small amounts in most

naturalfoods $dded from the salt shaker for avor Processin# techni.ues addsi#ni5cant

amounts of salt to the foods we buy

Sodium (6a

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7t serves "rimarily to hel" maintainnormal body8uid balance andosmotic"ressure

7t is critical for nerve im"ulsetransmission and musclecontraction

7t is a com"onent of severalcom"ounds

that hel" maintain normal acid8base

balance

Sodium functions in thebody

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%e5ciency states due to inade.uate dietary intakeare not common

Prolon#ed sweatin# while e9ercisin# in the heat

may lead to short8term de5ciencies that may bedebilitatin# to the athletic individual :ow sodium concentrations in the blood

cause a series of com"le9 reactions that lead tosecretion of aldosterone

$ldosterone stimulates the kidney to retain

more sodium 9cesses of serum sodium will lead to decreased

aldosterone "roduction and increased e9cretion ofsodium in the urine by the kidney

!ther hormones, notably $%&, hel" maintain

normal sodium e.uilibrium in the body uids

%e5ciency and e9cess

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The maor ne#ative ion in the e9tracellularuids stimated daily adult minimum re.uirement,;/0

milli#rams

%1 is

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stimated daily adult re.uirement, 2,000milli#ram %1 is

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Potassium balance is re#ulated byaldosterone

from the adrenal corte9 Potassium de5ciency may occur undercertain

conditions %urin# fastin# %urin# bouts with diarrhea >ith the use of diuretics

Sym"toms +uscular weakness

)ardiac arrest due to decreasedability to

#enerate nerve im"ulses

9cessive "otassium may cause cardiacarrh thmias and ossible death

%e5ciency and e9cess

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The tem"erature of body "arts may varyconsiderably )ore tem"erature Shell tem"erature

6ormal body tem"erature is a""ro9imately

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)ontrolled by the hy"othalamus The hy"othalamus receives in"ut from severalsources

?ece"tors in the skin Tem"erature of the blood

&eat loss if necessary The blood will be channeled closer to the

skin Sweatin# will be#in and eva"oration willcarry

away heat from the body The body will react to conserve heat or increaseheat

"roduction if necessary The blood will be shunted away from the

skin to

?e#ulation of *ody Tem"erature

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&y"othermia Fallin# into cold water Slower runners durin# the latter "art ofa

road race under cold, wet, and windyconditions

Sym"toms +uscular un8coordination +ental confusion

&y"erthermia !ne of the maor factors limitin#"hysical

"erformance

!ne of the most dan#erous factors

)onditions Threatenin# Tem"erature )ontr

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9ercise increases the metabolic rate and the"roduction of ener#y

The total amount of heat "roduced de"ends onthe

intensity and duration of e9ercise

The avera#e core tem"erature durin# e9ercisemay

reach about only A02328A043B0 F (

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&ow does environmental heat aect "hysical"erformance Performance in stren#th, "ower, or s"eed

events that last less than a minute does not

a""ear to be aected adversely by warmconditions Performance in more "rolon#ed aerobic

endurance activities is normally worse whencom"ared to "erformance in coolertem"eratures

7n more "rolon#ed events, above eects "luseects of dehydration

%ehydration and hy"ohydration may aecte9ercise

"erformance

Fluid and electrolyte losses

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Sweat is derived from the e9tracellular uids,BB

water The maor electrolytes found in sweat

Sodium and chloride !ther minerals lost in small amounts

Potassium, ma#nesium, calcium,iron, co""er, -inc

Small .uantities are "resent in sweat, but areeasily

restored with a balanced diet 6itro#en $mino acids

>ater8soluble vitamins

Sweat

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9ercise raises the concentration of several

electrolytes in the blood Sodium and "otassium

)hloride and calcium ion concentrationsremain

relatively unchan#ed durin# e9ercise +a#nesium levels in the blood usually fall 7t a""ears that an electrolyte de5ciency willnot occur 7f the electrolytes are not re"laced daily, a

de5ciencymay occur over time Prolon#ed sweatin# has been shown todecrease

the body content of sodium and chloride

by /8; ercent

lectrolyte *alance %urin# 9ercis

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Gucose8electrolyte solutions (GS Glucose8"olymer solutions

Provide carbohydrates while decreasin#the

osmotic concentration of the solution to

hel" minimi-e the eect u"on #astricem"tyin#

>hen dehydration or hy"erthermia is the maorthreat

to "erformance, water re"lacement is the

"rimary consideration 7n "rolon#ed endurance events, carbohydrate

re"lacement may hel" im"rove "erformance 7n very "rolon#ed e9ercise in the heat with heavysweat

losses, electrolyte re"lacement may be essential

Fluid and electrolyte re"lacement

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7t is the most eective way to enhance"erformance ?ehydration is recommended for wrestlers Fluid in#estion durin# "rolon#ed endurancee9ercise

+inimi-es the rise in core tem"erature ?educes stress on the cardiovascular systemby

minimi-in# the decrease in blood volume &el"s maintain an o"timal race "ace for alon#er

"eriod

>ater in#ested durin# e9ercise may a""ear in"lasma

and sweat within A0820 minutes 7f in#estion of sucient uids is not "ossibledurin#

e9ercise

?ehydration >hen 9ercisin# in the &

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Fluid volume Solute or caloric density

!smolality Fluid tem"erature 9ercise intensity +ode of e9ercise %ehydration

Factors 7nuencin# Gastric m"tyin#

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%urin# very "rolon#ed bouts of "hysical activity, electrolyte re"lacement may be necessary &y"onatremia sym"tomsH "ile"tic8like sei-ures &eavy daily sweat losses do not lead to anelectrolyte

de5ciency 7f electrolytes are not ade.uately re"laced ade5ciency may occur over 48; days of very hard trainin#,

es"ecially in hot conditions 9ercisin# individuals who e9"erience heavydaily sweat losses need both ade.uate uids and sodium toensure

ade.uate rehydration

lectrolyte ?e"lacement

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Guidelines for maintainin# body uid

balancebefore com"etition

*e well trained and acclimated *e ade.uately hydrated the daybefore

and the mornin# of com"etitionA08A; o-3 of cold uid A/8

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)old water, about 4348A00) is eective whencarbohydrate intake

is of little or no concern The uid should contain small amounts of electrolytes,4008A,A00

m# of sodium and A20822/ m# of "otassium "er liter ?ehydrate with AE08240 ml of cold uid durin# e9ercise at

A0 to A/minute intervals Start rehydratin# early in endurance events becausethirst does

not develo" until about A82 "ercent of body wei#ht hasbeen

dehydrated $fter com"etition durin# recovery, consume enou#h uidsto

re#ain your body wei#ht losses

7n trainin#, "ractice consumin# uids

Guidelines durin# com"etition

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%oes a""ear to enhance "erformance in e9ercisetasks

de"endent u"on the lactic acid ener#y systems The dosa#e of

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