title: Duration of caffeine abstention influences the acute blood pressure responses to caffeine in elderly normotensives.
abstract: The effect of an acute oral caffeine load (250 mg capsule) and matching placebo on blood pressure and pulse rate were studied after 48 h caffeine abstention in 8 elderly, normotensive regular caffeine users. The caffeine loading phase was repeated after only 12 h abstention. Following 48 h abstention, supine systolic and diastolic blood pressure were higher for the 120 min study period after the acute caffeine load than placebo (12.1 mm Hg, 95% C.I. 4.3-19.9 mm Hg; P = 0.008 and 7.4 mm Hg, 3.6-11.2 mm Hg; P < 0.001 respectively). Similar differences were seen in standing blood pressure, though pulse rate was unchanged throughout. The pressor response to the acute caffeine load was significantly greater after a 48 h than a 12 hour caffeine abstention period, for supine and standing systolic and diastolic blood pressure. The changes in plasma caffeine levels after acute loading were similar after the 2 different abstention periods. Caffeine ingestion after 48 h abstention has an acute pressor effect in normotensive elderly subjects which is abolished if the abstention period is reduced to 12 h. Acute caffeine ingestion is unlikely to have a significant pressor effect in elderly normotensive subjects who are regular caffeine users as the normal period of caffeine abstention (i.e. overnight) is too short to abolish tolerance.
authors.affiliation: University Department of Medicine for the Elderly, Leicester General Hospital, UK.
authors.forename: R A
authors.initials: RA
authors.lastname: Haigh
authors.forename: G D
authors.initials: GD
authors.lastname: Harper
authors.forename: M
authors.initials: M
authors.lastname: Fotherby
authors.forename: J
authors.initials: J
authors.lastname: Hurd
authors.forename: I A
authors.initials: IA
authors.lastname: Macdonald
authors.forename: J F
authors.initials: JF
authors.lastname: Potter
mesh_terms: D000284:Administration, Oral; D000368:Aged; D000369:Aged, 80 and over; D001794:Blood Pressure / Q000187:drug effects*; D002110:Caffeine / Q000008:administration & dosage / Q000097:blood / Q000494:pharmacology*; D005260:Female; D006801:Humans; D008297:Male; D011674:Pulse / Q000187:drug effects; D013997:Time Factors
chemical_list: D002110:Caffeine