Caffeine, attention, and alertness

EFSA support research that caffeine increases both selective attention (focusing on the relevant stimulus) and sustained attention (maintaining focused attention over an extended period of time)¹ and concluded that a 75mg serving of caffeine increased attention¹. Higher caffeine intakes do not necessarily result in additional increases in alertness⁶.

A 2020 meta-analysis concluded that caffeine intake was associated with improvements in a variety of test situations, including decreased response times and increased accuracy².

Caffeine, alertness, and safety in daily-life situations

The effects of caffeine on alertness are particularly applicable in daily life situations, with a 2020 meta-analysis observing a positive effect of caffeine on occupational performance; however, the magnitude of improvement varied widely². The potential role of caffeine when it comes to alertness may be beneficial in situations such as driving or coping with sleep loss commonly associated with shift work and jet lag.

Driving

Driving can be a monotonous task and a number of studies have reviewed the potential benefits of caffeine/coffee consumption on alertness, particularly during long drives.

A 2020 meta-analysis concluded that caffeine intake was associated with a large, significant effect on vehicle control in sleep restricted individuals². A large case-control study also revealed that caffeinated beverages, such as coffee, were associated with a reduced risk of crashing for long-distance commercial motor vehicle drivers⁷.  

Caffeine and memory

It has been reported that caffeine intake appears to improve working memory.

• A 2021 review suggests that caffeine may have positive effects on both short- and long-term memory in the adult and elderly populations, although subjective outcomes of caffeine consumption on cognitive performance and mood varied greatly⁵.
• A further 2021 review suggested that there is limited evidence that caffeine affects performance in memory tasks beyond improved reaction times. The authors commented on the need to control for habitual diet and sleep, as well as sex and age, dose, individual tolerance, and metabolism at baseline⁸. Further research is required in this area.