A Single Oral Dose of Caffeine Supports Sustained Attention and Alertness in Healthy Adults
Caffeine has a long history of use and is consumed by millions of people every day to help increase wakefulness, alleviate fatigue, and improve concentration and focus. Two of the most conventional ways to obtain caffeine is through coffee and tea, the most commonly consumed beverages in the world (energy drinks and sodas can also provide significant sources of caffeine). It is well-known that caffeine can induce positive effects on attention, although studies assessing the acute effects of a low caffeine dose (<75 mg) on sustained attention are limited and assessed with short-term tests.
A study published in the Journal of Psychopharmacology investigated the acute effects of a 60 mg dose of caffeine, compared to placebo, on sustained attention in tests lasting up to 45 minutes. Eighty two healthy adult males (n=41) and females (n=41) between the ages of 40 and 60 years with a history of low or non-caffeine usage participated in this study. Vigilance was assessed using Mackworth Clock test, Rapid Visual Information Processing Test, adaptive tracking test, saccadic eye movement and attention switch test. Effects on mood and fatigue were evaluated using Bond and Lader and Caffeine Research visual analogue scales, and Samn–Perelli questionnaire. Saliva samples were collected and analyzed for both compliance and caffeine pharmacokinetics.
Administration of a 60 mg caffeine dose resulted in a significant improvement in sustained attention compared with the placebo. In addition, a significantly improved peak saccadic velocity and reaction time performance was found, and a decreased error rate. Significantly improved feelings of alertness, contentment and overall mood after caffeine treatment compared with placebo were observed. This study demonstrates that in healthy adult subjects, oral administration of a single 60 mg dose of caffeine produces sustained attention and alertness, measured both in multiple objective performances and with subjective scales.