This document summarizes a study that tested the substrates utilized during submaximal exercise at different intensities. Two volunteers completed 20 minutes of steady-state exercise at low and moderate intensities while heart rate, blood pressure, and exertion levels were recorded. The results showed that heart rate and blood pressure increased more at moderate intensity. Both intensities utilized similar percentages of carbohydrates and lipids but the actual amounts utilized were higher at moderate intensity. In conclusion, the study demonstrated that carbohydrates and lipids are the main substrates used during exercise with amounts varying based on intensity and other individual factors.

1. Adoree Faul
Submaximal Exercise Testing
HES 403
11/9/15
Rationale
The purpose of thislab wasto conclude whichsubstratesare utilizedduring20minutesof steadystate
submaximal exercise.Itwasalsotounderstand if exercise intensityplayedasignificantrole onwhich
substrate wasto be utilizedforATP. Anotherimportantaspectof submaximal exercise isthatwe can
predictmaximal VO2 withouthavingthe patientactuallyexercisetotheirmaximal capacity.
Methods
The materialsusedtocollectthe data includedaHansRudoph2-way valve allowingthe subjectto
inspire roomairand thenexhale intothe analyzer.Two gasanalyzers,forO2 andfor CO2,wasusedto
measure eitherthe amountof infraredlighttransmittedthroughthe gasormeasuresthe change in
magneticfield afterintroducingoxygenandasubstrate thatproduceselectrical current.A
Pneumotachographwasusedmeasure instantaneousgasflow.Calibrationgasisthe knownmixture of
gasseswhichhelpscientistsreferencevaluesfor calibratingthe analyzers usedinthisstudy.
Aftercalibratingthe metaboliccart,2 volunteerscompleted20minutesof steady-stateexercise.Heart
rate,bloodpressure andrate perceivedexertion wasrecordedeveryfive minutes. Thissame experience
was thenduplicatedbutata higherworkloadonday2 of the experiment.

2. Results
In regardsto systolicbloodpressure,there wasabigincrease whenCarl wentfromlow exercise
intensitytomoderate. Mira,onthe otherhand,showedasmall decrease insystolicbloodpressure
whengoingfrommoderate intensitytolow. Withheartrate, againthe biggestchange wasseenwhen
comparingCarl’slowexercise intensitytohishighexercise intensity.Therewasalsoa large increase
seeninMira’s heartrate whengoingfromlow intensitytohighintensity.
Carl’sCHO utilizationatlowintensityexercise isapproximately 1.35g/minor about27 g total.
His %CHOutilizationatlowintensityisabout 64.20%.
Carl’slipidutilizationatlowintensityexercise is approximately .337 g/minor about6.74 g total.
His %lipidutilizationatlowintensityisabout 36.377%.
Carl’sCHO utilization atmoderate intensityexercise isapproximately 2.32g/minor about46.46 g total.
His %CHOutilizationatmoderate intensityisabout64.47%.
Carl’slipidutilization atmoderate intensityexercise isapproximately .58g/minorabout 11.52 g total.
His %lipidutilizationatmoderate intensityisabout36.11%.
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SBP DBP HR RPE
Carl Low
Carl Moderate
Mira Low
Mira Moderate

3. Conclusions
Accordingto the collecteddata, heartrate (HR) increasedtremendouslyinmoderate intensityexercise
vs.lowintensityexerciseasseeninbothvolunteers.Thiscausesthere tobe a largercardiac output(Q)
whichisthe product of HR and stroke volume (SV).SV plateausat40% VO2MAX whichmeans thatthe
increase inHR isthe onlyvariable thatisincreasingQ.SystolicBloodPressure (SBP) increasedinCarl’s
data whenhe wentfromlowintensityexercise tomoderate intensitybutMiraactuallyshowedasmall
decrease inherSBP.The decrease inSBPisunusual andcan be the resultof manythingsincluding
“aortic outflowobstruction,severe mitral disease,leftventriculardysfunctionorlimitedcomplianceof
the systemicventricle”.1
Althoughitisnotpossible todiagnoseorassume anyof these conditionsaftera
one-time datacollectionassessment,theseare possible andmore seriousreasonsfordecreasingSBP. In
bothmoderate andlowintensityexerciseitappearsthat%CHOutilizationand%lipidutilizationare only
a fractionof a percentapart. The amountof substratesutilizedwhenmeasureingramsonthe other
handis much higherinmoderate intensityexercise thanseeninlow.Itissuggestedthatplasmafree
fattyacids provide the majorityof the substrate oxidizedbyskeletal muscleduringlow-andmoderate-
intensityexercises.2
InourcollecteddataCHOutilizationisabout30% higherthanlipidutilizationinour
testedpatients. The utilizationof fatandcarbohydrate duringexercise canvaryenormouslydepending
on the individual,the type of exercise beingperformedandthe intensityof the exercise2
.Overall,CHO
and lipidsare majorsubstratesutilizedforATPduringexercise andthe amountof substrate used
dependsona varietyof factors.
References:
1. HouserM. Exercise bloodpressure incongenital heartdisease andinpatientsaftercoarctation
repair.National CenterforBiotechnologyInformation.2003 Feb.
2. Loon L. The effectsof increasingexerciseintensityof muscle fuel utilizationinhumans.National
CenterforBiotechnologyInformation.1995.