title: Caffeine administration does not alter salivary α-amylase activity in young male daily caffeine consumers.
abstract: BACKGROUND
  To follow up on a recent report from our lab [Hum Psychopharmacol 25:359-367, 2010.] we examined the effects of caffeine on salivary α-amylase (sAA) activity in response to an engaging, non-stressful task in healthy young males (age 18-30 yrs) who consumed caffeine on a daily basis. Using a placebo-controlled, double-blind, between-subjects design, 45 men received either placebo, 200 mg or 400 mg of caffeine (Vivarin®). Participants then rested for 20 minutes, and performed a 20-minute computerized air traffic controller-like task that was cognitively engaging but not stressful. Saliva samples (assayed for sAA and cortisol), blood pressure, and heart rate were taken before (baseline) and 15 minutes after the computerized task.
  
  
  RESULTS
  Systolic and diastolic blood pressure and sAA activity increased across the laboratory session (F's > 9.20, p's < 0.05); salivary cortisol levels decreased (F = 16.17, p < 0.05). There were no main effects for caffeine administration on sAA, salivary cortisol, or cardiovascular measures, and caffeine did not interact with the task to alter these measures.
  
  
  CONCLUSIONS
  Laboratory administered caffeine does not alter sAA activity, even when sAA activity is stimulated by participating in a cognitively engaging task. These data demonstrate that caffeine administration does not affect sAA activity, at least in healthy young men who regularly consume caffeine. Results support recent findings that basal caffeine levels in habitual caffeine users are not associated with basal sAA activity and that daily caffeine intake and diurnal sAA activity are not related.
authors.affiliation: Department of Biobehavioral Health & Penn State Institute of the Neurosciences, The Pennsylvania State University, 219 Biobehavioral Health Building, University Park, PA 16802, USA. lcklein@psu.edu.
authors.forename: Laura Cousino
authors.initials: LC
authors.lastname: Klein
authors.forename: Courtney A
authors.initials: CA
authors.lastname: Whetzel
authors.forename: Jeanette M
authors.initials: JM
authors.lastname: Bennett
authors.forename: Frank E
authors.initials: FE
authors.lastname: Ritter
authors.forename: Urs M
authors.initials: UM
authors.lastname: Nater
authors.forename: Michael
authors.initials: M
authors.lastname: Schoelles
mesh_terms: D000293:Adolescent; D000328:Adult; D001794:Blood Pressure / Q000187:drug effects; D015992:Body Mass Index; D002110:Caffeine / Q000494:pharmacology*; D000697:Central Nervous System Stimulants / Q000494:pharmacology*; D004311:Double-Blind Method; D006184:Habits; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D006854:Hydrocortisone / Q000032:analysis; D008297:Male; D011597:Psychomotor Performance; D012463:Saliva / Q000737:chemistry / Q000187:drug effects*; D055291:Salivary alpha-Amylases / Q000032:analysis*; D018910:Video Games; D055815:Young Adult
chemical_list: D000697:Central Nervous System Stimulants; D002110:Caffeine; D055291:Salivary alpha-Amylases; D006854:Hydrocortisone