Abstract

A host of factors which interact in a complex way with each other influence sports performance. Among ergogenic factors, caffeine is a socially acceptable stimulant (Burke, 2008) with known effects on different functional systems (Graham et al., 2008; Lieberman, 2001).
The majority of studies have been conducted on physical performance, showing controversial results in the literature (Astorino & Roberson, 2010; Harris, 2010) and to a lesser extent on cognitive functions (Lieberman, 2001). These discrepancies are primarily due to the different research designs and protocols used (Astorino et al., 2007; Jenkins et al., 2008). Generally speaking, they tend to highlight the beneficial effects on reaction times (Garrett & Griffiths, 1997; Popoli et al., 1998). There are virtually no studies analyzing the effect of caffeine on specific cognitive functions (Attwood et al., 2007; Michael et al., 2008) and in particular on any of the attentional networks. Only two authors (Brunyé et al., 2010a, 2010b; Huertas et al., 2011) have jointly analyzed the three attentional networks using Posner’s paradigm (Posner, 1978, 1980).
This was the point of departure of this doctoral dissertation, which is comprised of three experiments with the goal of ascertaining the effect of caffeine on the function of the condition of effort, more generally on the attentional function of executive control and more specifically on the function of alert and orientation. The cost and benefit paradigm (Posner et al., 1978) was used to record measurements of reaction time and percentage of errors according to different activity conditions (rest versus effort) and ingestion (caffeine versus placebo). The results include that acute aerobic exercise accelerates the reaction responses, which are quicker in the condition of effort than in rest, although caffeine does not modulate the response speed. Even more interesting was the reduction of the alert effect under the caffeine condition, as well as its relationship with consumption habit, as it was found that regular caffeine consumers show a higher alert effect than non-consumers. On the other hand, the activity condition also modulated the spatial and temporal orientation capacity, and the validity effect in the effort condition was higher.
It can be concluded that caffeine is the most popular ergogenic aid worldwide which produces improvements in the athlete’s performance, but that its treatment cannot be generalized; instead, the individual characteristics of each athlete should be borne in mind for this substance to have optimal results on athletic performance.