Clinical physiology and functional imaging
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Clin Physiol Funct Imaging · Jul 2009
Randomized Controlled TrialA preliminary investigation into the effect of coffee on hypolagesia associated with transcutaneous electrical nerve stimulation.
Transcutaneous electrical nerve stimulation (TENS) is a non-invasive, inexpensive analgesic technique used to relieve pain. It has been suggested that caffeine, an adenosine antagonist, may interfere with TENS action. This double-blind controlled pilot study investigated the effect of coffee on response to TENS in healthy human participants experiencing experimentally induced pain. ⋯ The statistical analysis modelled the responses for the coffee and decaffeinated coffee conditions during TENS (i.e. as a standard crossover) and detected no statistically significant effects between coffee and decaffeinated drinks for the natural logarithm (ln) transformed values of electrical pain threshold [ln EPT Coffee-ln EPT Decaffeinated coffee mean (standard error) = 0.0147 (0.2159)], mechanical pain threshold [ln MPT Coffee-ln MPT Decaffeinated coffee mean (standard error) = 0.1296 (0.0816)] and cold pain threshold [ln CPT Coffee-ln CPT Decaffeinated coffee mean (standard error) = 0.0793 (0.1139)]. We conclude that a single cup of coffee (100 mg caffeine) had no detectable effect on TENS outcome. Reasons why coffee did not produce a detectable effect on pain threshold are discussed.