Does caffeine intake enhance absolute levels of cognitive performance?
The relationship between habitual coffee and tea consumption and cognitive performance was examined using data from a cross-sectional survey of a representative sample of 9003 British adults (the Health and Lifestyle Survey). Subjects completed tests of simple reaction time, choice reaction time, incidental verbal memory, and visuo-spatial reasoning, in addition to providing self-reports of usual coffee and tea intake. After controlling extensively for potential confounding variables, a dose-response trend to improved performance with higher levels of coffee consumption was observed for all four tests (P<0.001 in each case). Similar but weaker associations were found for tea consumption, which were significant for simple reaction time (P=0.02) and visuo-spatial reasoning (P=0.013). Estimated overall caffeine consumption showed a dose-response relationship to improved cognitive performance (P<0.001 for each cognitive test, after controlling for confounders). Older people appeared to be more susceptible to the performance-improving effects of caffeine than were younger. The results suggest that tolerance to the performance-enhancing effects of caffeine, if it occurs at all, is incomplete.
Key wordsCaffeine Cognitive performance Coffee Tea
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- Barone JJ, Roberts H (1984) Human consumption of caffeine. In: Dews PB (ed) Caffeine. Springer, Berlin, pp 59–73Google Scholar
- Blanchard J, Sawers SJA (1983) Comparative pharmacokinetics of caffeine in young and elderly men. J Pharmacokinet Biopharm 11:109–126Google Scholar
- Brezinova V (1974) Effect of caffeine on sleep: EEG study in late middle age people. Br J Clin Pharmacol 1:203–208Google Scholar
- Clubley M, Bye CE, Henson TA, Peck AW, Riddington CJ (1979) Effects of caffeine and cyclizine alone and in combination on human performance, subjective effects and EEG activity. Br J Clin Pharmacol 7:157–163Google Scholar
- Cox BD, Blaxter M, Buckle ALJ, Fenner NP, Golding JF, Gore M et al. (1987) The health and lifestyle survey. Preliminary report of a nationwide survey of the physical and mental health, attitudes and lifestyle of a random sample of 9003 British adults. Health Promotion Research Trust, LondonGoogle Scholar
- Erikson GC, Hager LB, Houseworth C, Dungan J, Petros T, Beckwith BE (1985) The effects of caffeine on memory for word lists. Physiol Behav 35:47–51Google Scholar
- Frewer LJ, Lader M (1991) The effects of caffeine on two computerised tests of attention and vigilance. Hum Psychopharmacol 6:119–128Google Scholar
- Gilbert RM (1984) Caffeine consumption In: Spiller GA (ed) The Methylxanthine beverages and foods: chemistry, consumption and health effects. Liss, New York, pp 189–213Google Scholar
- Goldstein A, Kaizer S (1969) Psychotropic effects of caffeine in man. III. A questionnaire survey of coffee drinking and its effects in a group of housewives. Clin Pharmacol Ther 10:477–488Google Scholar
- Goldstein A, Kaizer S, Whitby O (1969) Psychotropic effects of caffeine in man. IV. Quantitative and qualitative differences associated with habituation to coffee. Clin Pharmacol Ther 10:489–497Google Scholar
- Griffiths RR, Woodson PP (1988) Caffeine physical dependence: a review of human and laboratory animal studies. Psychopharmacology 94:437–451Google Scholar
- Karacan I, Thornby JI, Anch M et al. (1977) Dose-related sleep disturbances induced by coffee and caffeine. Clin Pharmacol Ther 20:682–689Google Scholar
- Kerr JS, Sherwood N, Hindmarch I (1991) Separate and combined effects of the social drugs on psychomotor performance. Psychopharmacology 104:113–119Google Scholar
- Lieberman HR, Wartman RJ, Emde GG, Roberts C, Coviella ILG (1987) Effects of low doses of caffeine on human performance and mood. Psychopharmacology 92:308–312Google Scholar
- Loke WH (1988) Effects of caffeine on mood and memory. Physiol Behav 44:367–372Google Scholar
- Rall TW (1990) (In) Gilman AG, Rall TW, Nies AS, Taylor P (eds) The pharmacological basis of therapeutics, 8th ed. Pergamon Press, New York, pp 618–637Google Scholar
- Scott NR, Chakraborty J, Marks V (1989) Caffeine consumption in the United Kingdom: a retrospective survey. Food Sciences and Nutrition 42F:183–191Google Scholar
- Swift CG, Tiplady B (1988) The effects of age on the response to caffeine. Psychopharmacology 94:29–31Google Scholar
- Walsh JK, Muelbach MJ, Humm TM, Dickins QS, Sugerman JL, Schweitzer PK (1990) Effect of caffeine on physiological sleep tendency and ability to sustain wakefulness at night. Psychopharmacology 101:271–273Google Scholar
- Zwyghuizen-Doorenbos A, Roehrs TA, Lipschutz L, Timms V, Roth T (1990) Effects of caffeine on alertness. Psychopharmacology 100:36–39Google Scholar