The effects of caffeine on short-term, high-intensity exercise

2.50
Hdl Handle:
http://hdl.handle.net/10547/292660
Title:
The effects of caffeine on short-term, high-intensity exercise
Authors:
Doherty, Michael
Abstract:
This aim of this series of studies was to investigate the effects of oral caffeine ingestion (5 mg . kg-1) on whole-body, short-term, high-intensity exercise (ST; representing an exercise intensity of between 100% -150% V02 max), an area that has received scant attention in the past. It was found that, in common with other 'open-ended' tests, one ST assessment, the maximal accumulated oxygen deficit (MAOD), appeared to lack both validity and reliability. Although traditional reliability markers of MAOD were favourable, the 95% limits of agreement were unacceptably large. In addition, the validity of MAOD was also found to be questionable because a study of elite runners revealed that a large proportion were unable to accomplish a plateau in the V02 -exercise intensity relationship. A follow-up study developed an original bespoke 'preloaded' ST cycling protocol that combined constant-rate exercise with an 'all-out' effort. This protocol appears to have several features that make it a more appropriate assessment to use in ergogenic studies than the MAOD. The work also considered the original, and as yet, undeveloped potential, for the assessment of rating of perceived exertion (RPE) during ST. It was shown for the first time that RPE (Borg scale; 6-20) could be used reliably during constant-rate ST. Three of the ten studies demonstrated that caffeine can be ergogenic during ST, with improvements averaging 11 % (95% GI, 7.4% -14.5%) above placebo treatment. In addition, the caffeine studies contributed to a meta-analysis of the effects of caffeine on test outcome that resulted in an effect size greater than zero, with 95% confidence intervals not crossing zero. The studies have examined potential physiological and metabolic mechanisms of action that may help explain caffeine's impact on ST. These suggest that there is some evidence that caffeine both stimulates anaerobic glycolysis and reduces electrolyte disturbance during ST. Finally this work has demonstrated for the first time that the perceptual response during constant-rate ST, as measured by RPE, is blunted following caffeine ingestion. It is concluded that caffeine is ergogenic during ST, and that while the exact mechanism(s) of action remains unknown, one consistent test outcome is a reduction in RPE during constant-rate ST.
Citation:
Doherty, M. (2004) 'The effects of caffeine on short-term, high-intensity exercise'. PhD Thesis. University of Luton.
Publisher:
University of Bedfordshire
Issue Date:
Dec-2004
URI:
http://hdl.handle.net/10547/292660
Type:
Thesis or dissertation
Language:
en
Description:
A report submitted to the University of Luton, in partial fulfilment of the requirements for the degree of Doctor of Philosophy by Publications
Appears in Collections:
PhD e-theses

Full metadata record

DC FieldValue Language
dc.contributor.authorDoherty, Michaelen_GB
dc.date.accessioned2013-05-23T08:51:38Z-
dc.date.available2013-05-23T08:51:38Z-
dc.date.issued2004-12-
dc.identifier.citationDoherty, M. (2004) 'The effects of caffeine on short-term, high-intensity exercise'. PhD Thesis. University of Luton.en_GB
dc.identifier.urihttp://hdl.handle.net/10547/292660-
dc.descriptionA report submitted to the University of Luton, in partial fulfilment of the requirements for the degree of Doctor of Philosophy by Publicationsen_GB
dc.description.abstractThis aim of this series of studies was to investigate the effects of oral caffeine ingestion (5 mg . kg-1) on whole-body, short-term, high-intensity exercise (ST; representing an exercise intensity of between 100% -150% V02 max), an area that has received scant attention in the past. It was found that, in common with other 'open-ended' tests, one ST assessment, the maximal accumulated oxygen deficit (MAOD), appeared to lack both validity and reliability. Although traditional reliability markers of MAOD were favourable, the 95% limits of agreement were unacceptably large. In addition, the validity of MAOD was also found to be questionable because a study of elite runners revealed that a large proportion were unable to accomplish a plateau in the V02 -exercise intensity relationship. A follow-up study developed an original bespoke 'preloaded' ST cycling protocol that combined constant-rate exercise with an 'all-out' effort. This protocol appears to have several features that make it a more appropriate assessment to use in ergogenic studies than the MAOD. The work also considered the original, and as yet, undeveloped potential, for the assessment of rating of perceived exertion (RPE) during ST. It was shown for the first time that RPE (Borg scale; 6-20) could be used reliably during constant-rate ST. Three of the ten studies demonstrated that caffeine can be ergogenic during ST, with improvements averaging 11 % (95% GI, 7.4% -14.5%) above placebo treatment. In addition, the caffeine studies contributed to a meta-analysis of the effects of caffeine on test outcome that resulted in an effect size greater than zero, with 95% confidence intervals not crossing zero. The studies have examined potential physiological and metabolic mechanisms of action that may help explain caffeine's impact on ST. These suggest that there is some evidence that caffeine both stimulates anaerobic glycolysis and reduces electrolyte disturbance during ST. Finally this work has demonstrated for the first time that the perceptual response during constant-rate ST, as measured by RPE, is blunted following caffeine ingestion. It is concluded that caffeine is ergogenic during ST, and that while the exact mechanism(s) of action remains unknown, one consistent test outcome is a reduction in RPE during constant-rate ST.en_GB
dc.language.isoenen
dc.publisherUniversity of Bedfordshireen_GB
dc.subjectC600 Sports Scienceen_GB
dc.subjectcaffeineen_GB
dc.subjectsports scienceen_GB
dc.subjecthigh intensity exerciseen_GB
dc.titleThe effects of caffeine on short-term, high-intensity exerciseen
dc.typeThesis or dissertationen
dc.type.qualificationnamePhDen_GB
dc.type.qualificationlevelPhDen
dc.publisher.institutionUniversity of Bedfordshireen_GB
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