title: Acute exercise reduces caffeine-induced anxiogenesis.
abstract: OBJECTIVE
  This experiment examined the influence of acute exercise on anxiety following caffeine-induced elevations in self-rated anxiety.
  
  
  METHODS
  Eleven physically active, moderately fit males aged 25.1 +/- 3.8 yr completed four conditions in a within-subject, counterbalanced design involving 60 min of (1) cycling at 60% VO2peak or (2) quiet rest following placebo consumption (800 mg of lactose), as well as (3) cycling at 60% VO2peak and (4) quiet rest following 800 mg of caffeine. State anxiety and blood pressure were assessed 10 min before and 10 and 20 min after the conditions.
  
  
  RESULTS
  A main effect for drug (caffeine vs placebo) determined by repeated measures ANOVA, (F(1,8) = 9.77; P = 0.01), indicated that state anxiety was elevated by caffeine. Drug effects were not obtained for blood pressure. Experimental hypotheses were tested by drug-by-condition (exercise vs quiet rest)-by-time (10 and 20 min postcondition) repeated measures ANOVA of change scores from the precondition baseline. A main effect for drug (F(1,8) = 5.81; P = 0.043) indicated that reductions in state anxiety were larger after caffeine ingestion. A condition-by-time effect (F(1,8) = 5.02; P = 0.055) indicated greater reductions in state anxiety 20 min after exercise compared with quiet rest. A condition effect for systolic blood pressure (F(1,10) = 4.56; P = 0.058) and condition-by-time interactions for diastolic (F(1,10) = 8.87; P = 0.014) and mean arterial blood pressures (F(1,10) = 8.46; P = 0.016) indicated reductions after exercise but not after quiet rest following both caffeine and placebo.
  
  
  CONCLUSIONS
  We conclude that exercise can reduce anxiety elevated by a high dose of caffeine.
authors.affiliation: Department of Psychiatry, University of California, San Diego, La Jolla 92093, USA. syoungstedt@ucsd.edu
authors.forename: S D
authors.initials: SD
authors.lastname: Youngstedt
authors.forename: P J
authors.initials: PJ
authors.lastname: O'Connor
authors.forename: J B
authors.initials: JB
authors.lastname: Crabbe
authors.forename: R K
authors.initials: RK
authors.lastname: Dishman
mesh_terms: D000328:Adult; D001007:Anxiety / Q000139:chemically induced* / Q000628:therapy*; D001642:Bicycling; D001794:Blood Pressure / Q000187:drug effects; D002110:Caffeine / Q000009:adverse effects*; D000697:Central Nervous System Stimulants / Q000009:adverse effects*; D015444:Exercise / Q000523:psychology; D005081:Exercise Therapy; D006801:Humans; D008297:Male
chemical_list: D000697:Central Nervous System Stimulants; D002110:Caffeine