Central and peripheral effects of sustained caffeine use: tolerance is incomplete

J Watson, I Deary, D Kerr

Research output: Contribution to journalArticlepeer-review

Abstract / Description of output

Aims It is widely held that tolerance develops to the effects of sustained caffeine consumption. This study was designed to investigate the effects of chronic, staggered caffeine ingestion on the responses of an acute caffeine challenge, during euglycaemia.

Methods Twelve healthy volunteers were randomized using a double-blind, crossover design to take either 200 mg caffeine (C-replete) or placebo (C-naive) twice daily for 1 week. Following baseline measurements being made, the responses to 200 mg caffeine (blood-pressure, middle cerebral artery velocity, mood and cognitive performance) were examined over the subsequent 120 min. Blood glucose was not allowed to fall below 4.0 mmol l(-1).

Results After the caffeine challenge, middle cerebral artery blood velocity decreased in both conditions but was greater in the C-naive condition (-8.0 [-10.0, -6.1] cm s(-1) vs -4.9 [-6.8, -2.9] cm s(-1) C-replete, P < 0.02). Systolic blood pressure rise was not significantly different in C-naive, although this rise was more sustained over time (P < 0.04). Mood was adversely affected by regular caffeine consumption with tense aspect of mood significantly higher at baseline in C-replete 11.6 +/- 0.6 C-naive vs 16.3 +/- 1.6 C-replete, P < 0.01). Cognitive performance was not affected by previous caffeine exposure.

Conclusions Overall these results suggest that tolerance is incomplete with respect to both peripheral or central effects of caffeine.

Original languageEnglish
Pages (from-to)400-406
Number of pages7
JournalBritish Journal of Clinical Pharmacology
Issue number4
Publication statusPublished - Oct 2002

Keywords / Materials (for Non-textual outputs)

  • caffeine
  • caffeine-tolerance
  • euglycaemia
  • MOOD


Dive into the research topics of 'Central and peripheral effects of sustained caffeine use: tolerance is incomplete'. Together they form a unique fingerprint.

Cite this