Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
10
pubmed:dateCreated
1988-4-22
pubmed:abstractText
Caffeine use during exposure to mental stress is an extremely common occurrence. Because both have been shown to alter blood pressure (BP) and its underlying hemodynamic mechanisms, the potential exists for additive or even synergistic effects. Changes in heart rate, BP and noninvasive thoracic impedance measures of left ventricular function were examined in young men (ages 20 to 36) at rest and during a demanding behavioral task performed 40 minutes after predosing with caffeine (3.3 mg/kg, equivalent to 2 to 3 cups of coffee) or placebo in a double-blind crossover design. All subjects were healthy young men without history of cardiovascular disease, regular use of nicotine, recreational or prescription drugs or caffeine intolerance. Caffeine abstinence was required for 12 hours before each test session. Systolic and diastolic BP were elevated by both caffeine and the behavioral task alone (p less than 0.01 for each); when combined, caffeine's pressor effects were additive to those of the behavioral task. However, caffeine's pressor effect was produced by different mechanisms depending on the behavioral state. Caffeine increased systemic vascular resistance (p less than 0.01) under resting conditions, but it enhanced cardiac output (p less than 0.01) during behavioral arousal associated with the task. The combined influence of caffeine and the task increased the number of men in whom peak systolic BP reached hypertensive levels, and also synergistically increased cardiac minute work (p less than 0.01) and the rate-pressure product estimate of myocardial oxygen demand (p less than 0.05). Implications of these findings are discussed for long standing theoretical disputes regarding caffeine, its health consequences, and for methodologic issues in behavioral and clinical studies.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
AIM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Apr
pubmed:issn
0002-9149
pubmed:author
pubmed:issnType
Print
pubmed:day
1
pubmed:volume
61
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
798-802
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1988
pubmed:articleTitle
Effect of behavior state on caffeine's ability to alter blood pressure.
pubmed:affiliation
Veterans Administration Medical Center, Behavioral Sciences Laboratories, Oklahoma City, Oklahoma 73104.
pubmed:publicationType
Journal Article, Clinical Trial, Comparative Study, Research Support, U.S. Gov't, Non-P.H.S., Controlled Clinical Trial