Purpose:Thepurposeofthisstudywastoexamine,usingmeta-analyticmeasures,theevidenceregardingtheoptimalexerciseintensityatwhichimprovementsinspeedofcognitivefunctionaretriggered.Specifically,itwashypothesizedthatthecatecholamine,lactate,andventilatorythresholdsisthepointatwhichsignificantimprovementsinspeedofcognitivefunctionareobserved.Methods:Wecomparedmeaneffectsizesforthresholdstudiesandforthosestudieswhereexerciseintensitywasclassedasmoderate(40%e79%VO2maxorequivalent)butinwhichthethresholdswerenotmeasured.Results:Randomeffectsmeta-analysisshowedsignificant,moderate,meaneffectsizesforstudiesatthethreshold(g=0.58,Z=2.98,p<0.003)andforthoseduringmoderateintensityexercisebutinwhichthethresholdwasnotmeasured(g=0.54,Z=5.01,p<0.001).Therewasnosignificantdifferencebetweenmeaneffectsizes,whichsuggeststhatthethresholdsareunlikelytorepresentatriggerpoint.Conclusion:Moderateintensityexercise,evenbelowthethresholds,caninduceimprovedspeedofcognition,possiblyduetoacombinationofincreasedperipheralcatecholamineconcentrationsinducingvagal/nucleustractussolitariipathwayactivationandcentralincreasesduetoperceptionsofstress.
