Caffeine and Cognitive Performance

If you’ve ever listened closely to conversations in the workplace, you've likely heard:

• “I’ll get started on it only after I’ve had my coffee.”

• “I can’t function without my morning cup of coffee!”

• “Where are the interns!? They were supposed to go on a coffee run an hour ago.”

We all know the high level of importance coffee, tea, and other caffeinated beverages have in our day-to-day life, but what exactly is caffeine’s role in our cognitive function? Today we examine the effects caffeine has on our mental state, dispel some myths, and examine the long-term effects it may hold as we age. We’ll also talk about how you can optimize your caffeine consumption to maximize benefits and limit the possible negative effects of withdrawal, jitteriness and sleeplessness.

Caffeine’s Primary Mechanism

Caffeine’s greatest contribution in optimizing our productivity is in its effects of what is collectively known as “lower” cognition or the types of mental processes that we don’t actively think about. Examples of these processes include your level of alertness, focus, attention, reaction speed and mental stamina.

A large body of evidence shows that caffeine provides benefits across these processes by an underlying mechanism of tricking your body into thinking it’s not tired (1). Caffeine works by structurally mimicking adenosine, a natural metabolic byproduct to many cellular processes that can build up over time. Normally accumulating adenosine increasingly binds to and activates their target receptors (most notably to the A1 and A2a subtype) which in turn triggers pathways to slow down active brain processes that we attribute to tiredness. However, where caffeine differs is when it binds to these adenosine receptors, it instead works as an antagonist and blocks it. This gives caffeine an effect similar to taking off the brakes.

When the receptor is blocked, there is an increase in nature’s stimulatory neurotransmitters such as dopamine and glutamate that result in many of the physiological effects we attribute to caffeine (2). You may recognize dopamine as the “feel good” neurotransmitter, which is also why we get mood boosts when consuming caffeine (3).

The downside to all that caffeine drinking and adenosine receptor blocking is that your body will try to go back to normal state in the presence of caffeine. Your body may begin to produce more adenosine receptors and caffeine metabolism enzymes, meaning you can build up a tolerance to its beneficial effects and get feelings of withdrawal which commonly presents as a headache. Luckily, your body can return back to normal after a week or two of cutting back on caffeine (4). Your tolerance to caffeine and beneficial effect size will vary according to your own genetic profile, diet, and tiredness.

Is There an Effect on “Higher” Cognition?

We know caffeine can benefit our lower cognition, but does it have an effect on cognition higher up, such as active thinking and decision-making processes? While the current body of literature suggests that caffeine may not directly alter these cognitive processes, the benefits of caffeine for lower cognitive functions may help explain why it still feels easier to perform a variety of tasks and engage in complex decision-making.

This was shown in recent study of young adults looking at the effect of caffeine on an assessment testing logical reasoning and information processing (5). Despite no differences in the assessment scoring when compared to placebo water consumption, the study did still find benefits of increased mood and a positive perception related to completing the assessments.

Similarly, other trials have looked at consciously aware activities such as completing skilled tasks, recalling information from long-term memory, and strategic thinking. Little direct improvements were seen with exception to variations attributed to the already known lower cognitive improvements (6). To summarize, caffeine won’t necessarily make you smarter, but it will help your inner intelligence to better shine through!

Slowing Cognitive Decline

Several studies have shown an association with regular caffeine intake and decreased risk for neurodegenerative disorders such as Parkinson’s Disease.

Caffeine’s blocking of the adenosine A2a receptors increases the release of dopamine by blocking A2a’s association with dopamine receptors D1 and D2. The increased dopamine may provide some protection against Parkinson’s disease and may also actually help with the movement disorder symptoms caused by the low levels of dopamine (7).

In one study, caffeine helped to diminish the symptoms of Parkinsonian movement disorders including lessening muscle rigidity to allow easier movement and reducing motion tremor at rest (8). Studies have also associated regular caffeine intake with slowing down the natural cognitive decline in elderly adults, including lower risk for dementia and Alzheimer’s Disease (9, 10, 11).

Tips for Consumption

The caffeine in coffee, tea, and other beverages can be very beneficial to optimizing your productivity. Finding that perfect amount for consumption can be challenging, but knowing your genetic sensitivities and metabolism can help.

Remember too much caffeine can be just as detrimental as too little. Overconsumption of caffeine can leave you jittery, anxious, and more prone to withdrawal symptoms (12).

A good target is staying below 300mg or about 3 cups of coffee per day (6). Regular consumption may also reduce your risk for neurodegenerative diseases later in life and slow the natural cognitive decline. And while caffeine may not be the most important factor in getting work done, it likely can help you along the way.

Want to find out how your body is predisposed to metabolizing caffeine? Take a look at your caffeine genes in your Health Action Plan and get a better understanding of how caffeine affects you and your health.

References:

1. Nehlig A. Is caffeine a cognitive enhancer? J Alzheimer’s Disease. 2010; 20: S85-S94.

2. Ferré S. Role of central ascending neurotransmitter systems in the psychstimulant effects of caffeine. J Alzheimer’s Disease. 2010; 20: S35-S49.

3. Volkow ND, Wang GJ, Logan J, et al. Caffeine increases striatal dopamine D2/D3 receptor availability in the human brain. Trasl Psychiatry. 2015; 5: e549.

4. Juliano LM, Griffiths RR. A critical review of caffeine withdrawal: empirical validation of symptoms and signs, incidence, severity, and associated features.

5. Ullrich S, de Vries YC, Kühn S, Reapntis D, Dresler M, Ohla K. Feeling smart: effects of caffeine and glucose on cognition, mood and self-judgment. Physio & Behav 2015; 151:629-637.

6. McLellan TM, Caldwell JA, Lieberman HR. A review of caffeine’s effects on cognitive, physical and occupational performance. Neuro & Behav Rev. 2016; 71: 294-312.

7. Prediger RDS. Effects of caffeine in Parkinson’s Disease: from neuroprotection to the management of motor and non-motor symptoms. J Alzheimer’s Disease. 2010. S205-S220.

8. Bara-Jimenez W, Sherzai A, Dimitrova T, Favit A, et al. Adenosine A2A receptor antagonist treatment of Parkinson’s disease. Neurology 2003; 61: 293 - 296

9. Eskelinen MH, Ngandu T, Tuomilehto J, Soininen H, Kivipelto M. Midlife coffee and tea drinking and the risk of late-life dementia: a population-based CAIDE study. J Alzheimer’s Disease. 2009; 16:85-91.

10. Panza F, Solfrizzi V, Barulli MR, et al. Coffee, tea, and caffeine consumption and prevention of late-life cognitive decline and dementia: a systematic review. J Natr Health Aging. 2015; 19(3): 313 - 328.

11. Carmen AJ, Dacks PA, Lane RF, Shineman DW, Fillit HM. Current evidence for the use of coffee and caffeine to prevent age-related cognitive decline and Alzheimer’s Disease. J Nutrition, Health & Aging. 2014; 18(4): 383 - 392.

12. Stafford, L.D., Rusted, J., Yeomans, M.R., 2007. Caffeine, mood, and performance. A selective review. In: Smith, B.D., Gupta, U., Gupta, B.S. (Eds.), Caffeine and Activation Theory: Effects on Health and Behavior. Taylor and Francis, Boca Raton, FL, pp. 284–310.