EXSC 326 CH 9 Powerpoint

7/23/2019 EXSC 326 CH 9 Powerpoint

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+

Chapter Nine

EXSC 326


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+Metabolism

Involves all chemical reactions ofbiomolecules within the body that encompasssynthesis anabolism! " brea#down

catabolism!$hree factors a%ect total daily ener&y e'penditure

$(EE!)

*estin& metabolic rate+ consistin& of basal and

sleepin& conditions plus the metabolic cost of arousal $hermo&enic e%ect of food consumed

Ener&y e'pended durin& physical activity " recovery


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+Component

s of totaldaily ener&ye'penditure


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+,asal " *estin& Metabolic *ates

,asal Metabolic *ate ,M*!

Minimum level of ener&y to sustain vital

functions in the wa#in& state

*e-ects the body.s total heat production

*estin& Metabolic *ate *M*!

/lways sli&htly hi&her than ,M*

In-uences) body si0e+ health1tness+muscle mass+ a&e+ hormones+ bodytemperature


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+,asal " *estin& Metabolic *ates

,M* and *M* sum of metabolicprocesses re4uired to sustain normal

regulatory balance and bodyfunctions durin& the restin& state

5'y&en consumption values for ,M*

ran&e between 67 and 287 m91min7:; to :


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+Metabolic Si0e Concept

Surface /rea 9aw fundamental relationshipbetween heat production and body si0e! ,M* and *M* vary in proportion to the s4uare of body

surface area per hour #cal1m21h! =emales have > to 7? lower ,M* than males of the

same a&e " si0e frommore fat " less fat@free mass

$heconcept of metabolic si0erelates ,M* tobody mass raised to the 7:A> power ,M7:A>!

,M* e'pressed relative to ,M7:A>holds true forhumans " most mammals " birds that di%erconsiderably in si0e and shape


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+9o&arithmicBlot of ,ody

Mass "Metabolic*ate atts!

for ,irds "Mammals of(i%erent

Si0e andShape


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+Metabolic *ates of Dumans)

/&e and ender ComparisonsEstimates of ,M* or *M* fall within F7? of

laboratory values

Chan&es in body composition decrease in ==Mand1or increase in ?body fat! can e'plain the2 to 3? per decade ,M* reductionobservedfor adults

=emales e'hibit an avera&e > to7? lower ,M*than males of same a&e (ue to less fat@free mass and more body fat fat has

lower metabolic activity than muscle!


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+,M* as a =unction

of /&eand ender


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+E%ects of *e&ular Bhysical

/ctivity on ,M**e&ular physical activity endurance "

resistance e'ercise! o%sets decreases in ,M*and *M* that occur with a&in&

Estimatin& *estin& (aily Ener&y E'penditure*(EE!

Gsually e'pressed in #cal1h or #cal1d Can be estimated from ,M* #cal1m21h! and surface

area m2!

Can be estimated from fat@free mass ==M!

*(EE #cal1d! 3A7 H ==M #&!


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+Estimates of absolute and

relative 52upta#e of variousadult or&ans " tissues

Organ

OxygenConsumption (mL

min1)

% of RestingMetabolism

9iver 6A 3A

,rain


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+=ive =actors $hat /%ect $(EE

: Bhysical /ctivity

2: (iet@induced thermo&enesis

3: Calori&enic e%ect of food on e'ercisemetabolism

: Bre&nancy


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+Bhysical /ctivity /%ects on

$(EEBhysical activity e'erts by far the most profound

e%ect on human ener&y e'penditure /ccounts for > to 37? of $(EE

*e&ular physicalactivity stimulates restin&metabolism

*e&ular endurance " resistance e'ercise o%sets

the decrease in restin& metabolism that usuallyaccompanies a&in&

Each @lb &ain in ==M increases *M* by A to 7#cal1d


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+(iet@Induced $hermo&enesis

(I$!or the $hermic E%ect of =ood$E=! =ood consumption increases ener&y

metabolism 5bli&atory thermo&enesis) Ener&y re4uired to

di&est+ absorb+ and assimilate food nutrients =acultative thermo&enesis) /ctivation of sympathetic

nervous system and its stimulatin& in-uence onmetabolism: *eaches ma'imum within hour followin&a meal

5verwei&ht individuals often have a bluntedthermic response lowered metabolism! thatcontributes to e'cess body fat accumulation


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+Calori&enic E%ect of =ood onE'ercise Metabolism

$he calori&enic e%ect of food on e'ercisemetabolism nearly doubles the food.s thermice%ect at rest

(I$ of carbohydrate and protein e'ceedslipid(I$

=or most individuals+ it seems reasonable

to encoura&e moderate physical activity aftereatin& to possibly au&ment a diet@inducedincrease in caloric e'penditure for wei&htcontrol


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+Climate

Environmental factors in-uence metabolic rate

*M* of people in a tropical climate avera&es > to 27?hi&her than those livin& in temperate areas

E'ercisin& in hot weather causes about a >? hi&her 52

consumption

*esults from an elevated core temperature+ ener&y forsweat &land activity and altered circulatory dynamics

Cold environments increase ener&y metabolism durin&rest and e'ercise

(epends on body fat content and e%ectiveness ofclothin&


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+Bre&nancy

/dded ener&y cost of wei&ht@bearin&locomotion durin& pre&nancy results

primarily from)/dditional wei&ht transported

*educed economy of e%ort fromencumbrance

of fetal tissue


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+Classication of Bhysical/ctivities by Ener&yE'penditure:Classifyin& strenuousness of physical tas#s) Intensity how KhardL you perform can be

based on ?52ma'!

(uration how lon& you perform activity!

2:Bhysical /ctivity *atio B/*! Classies wor# as the ratio of ener&y re4uired for a

tas# to the restin& ener&y re4uirement

9i&ht wor#) Gp to 3 times the restin&re4uirementDeavy wor#) 6 to ; times restin&

metabolismMa'imal wor#) 8 times or more above rest


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+$he ME$

ME$+ metabolic e4uivalent)Multiples of *M*

5ne ME$ e4uals restin& o'y&en consumptionor 2>7 m91min for men and 277 m91min forwomen

E'ercise at 2 ME$s re4uires twice the restin&

metabolism+ 3 ME$s e4uals three times rest+etc:

$o consider variations in body si0e+ e'pressME$s in 52per unit body mass

ME$ e4uals 3:> m91#&1min


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+=ive@9evel Classication of B/,ased on Ener&y E'penditure

Leel!nergy !xpen"iture

#cal min1 L min1 mL #g min1 M!$

Men

9i&ht 2:7:7A:< :77::322:8 :8

Deavy A:>8:8 :>7:88 23:737:6 6:7A:8

ery heavy 7:72:< 2:772: O2:>7 O3;:< O7:7

&omen

9i&ht :>3:< 7:377:68 >: :22:A

Moderate 3:>>:< 7:A7:78 2:68:; 2:;:>A:< :7:7:;8 2A:23

Gnduly heavy O8:> O:87 O3 OA:6


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+(aily *ates of /vera&e Ener&yE'penditure

$he avera&e man8@>7y! e'pends2877 #cal1d the

avera&e womene'pends 2277 #cal1d Most people spend nearly

A>? of their day in li&htener&y e'penditureactivities P;h sleep1lyin&down 6h standin& 2hwal#in&1recreationalactivitiesQ

'en"er ge an" !nergy !xpen"iture

ge (y)

!nergy!xpen"iture

(#cal)

Males >@; 3777

8@2< 2877

2>@>7 2877

>H 2377

*emales >@; 2277

8@2< 2277

2>@>7 2277

>H 877


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+Ener&y Cost of Dousehold+Industrial+ " *ecreational/ctivitiesSee /ppendi' =+ online at

http)11thepoint:lww:com1m##;e

for e'amples of ener&y e'penditures e'pressed

as #cal1#& body mass for common householdactivities+ selected industrial tas#s+ and popular

recreational and sports activities
http://thepoint.lww.com/mkk8ehttp://thepoint.lww.com/mkk8e


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+In-uence of ,ody Mass

Increases in body mass raise ener&y e'pendedin many activities+ especially in wei&ht@bearin&e'ercise

ith wei&ht@supported e'ercise e:&: stationary cyclin&!+the in-uence of body mass on ener&y cost decreasesconsiderably

=or overwei&ht persons+ wei&ht@bearin& e'ercise&enerates a considerablecaloric e'penditure

E'pressin& ener&y cost per #& of body massreducesener&y cost di%erences betweenindividuals re&ardless of a&e+ race+ &ender+ andbody mass


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+*elationship,etween,ody Mass "5'y&en

Consumption(urin&al#in&


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+Deart *ate to Estimate Ener&yE'penditure

=or each individual+ heart rate D*! and 52

relate linearly over theran&e of e'erciseintensities to about ;7? of ma'imum

E'ercise D* can provide an estimate of 52and thus

ener&y e'penditure durin&aerobic e'ercise

Many factors independent of and in addition toe'ercise limit the use of e'ercise D* to estimate

ener&y e'penditure environmental temperature+ emotions+ food inta#e+

body position+ musculature+ continuous vs:discontinuous mode+ static or dynamic movements


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+E'ample

9inear relationshipbetween heart rate"52for two female

bas#etball players

of di%erent aerobictness levels

Note di%erences inthe slopes of thetwo lines+ indicatin&

di%erent tnesslevels yellow linemore t person!

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EXSC 326 CH 9 Powerpoint