Acute effects of caffeine in volunteers with different patterns of regular consumption
John Wiley & Sons Ltd.
MetadataDangos cofnod eitem llawn
Rationale The effects of caffeine on mood and performance are well established. One explanation of these effects is that caffeine removes negative effects induced by prior caffeine withdrawal. This was tested here by comparing effects of caffeine in withdrawn consumers and non-consumers (who by definition were not withdrawn). Objectives The present study aimed to determine whether caffeine withdrawal influenced mood and performance by comparing regular consumers who had been withdrawn from caffeine overnight with non-consumers. Following this the effects of acute caffeine challenges were compared in withdrawn consumers and non-consumers. In addition, comparisons were made between those with higher and lower caffeine consumption. Methods One hundred seventy-six volunteers participated in the study. Regular caffeine consumption was assessed by questionnaire and this showed that 56 of the sample did not regularly consume caffeinated beverages. Volunteers were instructed to abstain from caffeine overnight and then completed a baseline session measuring mood and a range of cognitive functions at 08.00 the next day. Following this approximately half of the volunteers were given 1 mg/kg caffeine in a milkshake or water (in the ‘no caffeine’ condition they were given just the milkshake or water) and the test battery repeated one hour later. A second test battery was carried out at 12.00 and a second caffeine challenge at 13.00. A final test session was carried out at 15.00. Results The baseline data revealed little evidence of effects of caffeine withdrawal on performance and mood. In contrast to this, caffeine produced a number of significant improvements in performance. There were some differences in the effects of caffeine on regular and non-consumers, with caffeine tending to reduce reaction time in regular consumers while the opposite was true for non-consumers. Conclusions The present results show little evidence of effects of caffeine withdrawal on performance. In contrast, caffeine challenge produced improvements in aspects of performance and these were often not modified by regular caffeine consumption patterns. The differences in effects of caffeine that were observed between non-consumers and regular consumers were in functions that were unaffected by caffeine withdrawal. These findings show that the observed beneficial effects of caffeine cannot be interpreted in terms of a reversal of caffeine withdrawal.
Human Psychopharmacology: Clinical and Experimental
Hewlett, Paul & Smith, A. (2006). Human Psychopharmacology-Clinical and Experimental 21 (3), pp.167-180
Dynodwr Gwrthrych Digidol (DOI)http://dx.doi.org/10.1002/hup.752
Yn dangos eitemau sy’n perthyn drwy deitl, awdur, pwnc a chrynodeb.
Effects of Reapeated Doses of Caffeine on Performance and Alertness: New Data and Secondary Analyses Hewlett, Paul; Smith, Andrew (Wiley, 2007)Rationale The effects of caffeine on mood and performance are well established. Some authors suggest that caffeine merely reverses effects of caffeine withdrawal rather than having direct behavioural effects. It has also ...
To explore the intake, knowledge and perceived perceptions of caffeine consumption on performance within a population of elite hockey players McClements, Jane (2018-04-01)Background: Previous literature has debated the effectiveness of caffeine as a stimulant on specific aspects of an athlete’s performance. Although associations have been drawn between caffeine consumption and performance ...
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