Abstract
BackgroundAcute caffeine ingestion has been associated with improvements in cognitive performance and visual functioning. The main objective of this study was to determine the effects of caffeine intake on dynamic visual acuity (DVA).MethodsTwenty-one low caffeine consumers (22.5 ± 1.6 years) took part in this placebo-controlled, double-blind, and balanced crossover study. In two different days and following a random order, participants ingested either caffeine (4 mg/kg) or placebo, and DVA was measured after 60 min of ingesting the corresponding capsule. A recently developed and validated software (moV& test, V&mp Vision Suite, Waterloo, Canada) was used to assess DVA.ResultsWe found a greater accuracy for both the horizontal and random motion paths of DVA after caffeine ingestion (p < 0.001 and p = 0.002, respectively). In regard to the speed of the response, our data revealed that caffeine intake was associated with a faster reaction time for horizontally (p = 0.012) but not for randomly (p = 0.846) moving targets. Also, participants reported higher levels of perceived activation after consuming caffeine in comparison to placebo (p < 0.001).ConclusionsOur data suggest that caffeine intake (i.e., a capsule containing 4 mg/kg) has an ergogenic effect on DVA, which may be of special relevance in real-word contexts that require to accurately and rapidly detect moving targets (e.g., sports, driving, or piloting).
Highlights
Dynamic visual acuity (DVA) is defined as the ability to resolve fine details when there is relative motion between the target and the observer (Miller and Ludvigh 1962)
Research has demonstrated that dynamic visual acuity (DVA) plays an important role in multiple real-word situations, mainly in those that involve operating in dynamic environments with moving objects such as different ball sports (Ishigaki and Miyao 1993; Quevedo-Junyent et al 2011), driving (Hwang et al 2020), and piloting (Kohl et al 1991; Peters et al 2011)
We performed two separate paired samples t-tests for the subjective scores of activation in both experimental sessions, considering the point of measure as the only within-participants factor. These analyses revealed that participants reported higher levels of activation after caffeine intake (t20 = 8.22, p < 0.001, d = 1.79), but not after ingesting the placebo capsule (t20 = 0.34, p = 0.741, d = 0.08) (Fig. 1)
Summary
Dynamic visual acuity (DVA) is defined as the ability to resolve fine details when there is relative motion between the target and the observer (Miller and Ludvigh 1962). Recent scientific evidence indicates that caffeine intake has an effect on different visual skills such as contrast sensitivity (Tsunoda et al 2019), ocular aberrations. The main objective of this study was to determine the effects of caffeine intake on dynamic visual acuity (DVA). In regard to the speed of the response, our data revealed that caffeine intake was associated with a faster reaction time for horizontally (p = 0.012) but not for randomly (p = 0.846) moving targets. Conclusions Our data suggest that caffeine intake (i.e., a capsule containing 4 mg/kg) has an ergogenic effect on DVA, which may be of special relevance in real-word contexts that require to accurately and rapidly detect moving targets (e.g., sports, driving, or piloting)
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