title: Effect of intrinsic sympathomimetic activity on the ability of hypertensive patients to derive a cardiorespiratory training effect during chronic beta-blockade.
abstract: The effect of intrinsic sympathomimetic activity (ISA) on the ability of patients with high blood pressure (BP) to derive a cardiorespiratory training effect during long-term beta-blocker therapy was studied. Fifty sedentary hypertensive subjects were randomly assigned to propranolol (n = 23) or pindolol (n = 27) therapy for a 22 week double-blind parallel study. Over the first 2 weeks, during which subjects remained sedentary, drug doses were titrated to produce equipotent, clinically significant BP reductions. Subjects subsequently continued drug therapy and completed 20 weeks of exercise training. Although pindolol tended to preserve submaximal exercise heart rates to a greater degree than propranolol, the initial 2 weeks of drug therapy resulted in equivalent reductions in maximal oxygen uptake with propranolol (6% reduction) and pindolol (8% reduction). Likewise, 20 weeks of training induced similar, statistically significant (P = .0001) increases in maximal oxygen uptake during propranolol (10% increase) and pindolol (11% increase) treatment. We therefore conclude that ISA does not confer any advantage to patients with high BP who receive chronic beta-blocker therapy and wish to improve their cardiorespiratory fitness by participating in exercise training.
authors.affiliation: Institute for Aerobics Research, Dallas, TX 75230.
authors.forename: J J
authors.initials: JJ
authors.lastname: Duncan
authors.forename: H
authors.initials: H
authors.lastname: Vaandrager
authors.forename: J E
authors.initials: JE
authors.lastname: Farr
authors.forename: H W
authors.initials: HW
authors.lastname: Kohl
authors.forename: N F
authors.initials: NF
authors.lastname: Gordon
mesh_terms: D000319:Adrenergic beta-Antagonists / Q000627:therapeutic use*; D001794:Blood Pressure / Q000187:drug effects; D003131:Combined Modality Therapy; D004311:Double-Blind Method; D005081:Exercise Therapy; D005260:Female; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D006973:Hypertension / Q000628:therapy*; D008297:Male; D010101:Oxygen Consumption / Q000187:drug effects; D010869:Pindolol / Q000627:therapeutic use; D011433:Propranolol / Q000627:therapeutic use; D016032:Randomized Controlled Trials as Topic; D012137:Respiratory System / Q000187:drug effects; D016037:Single-Blind Method; D013566:Sympathomimetics / Q000627:therapeutic use*
chemical_list: D000319:Adrenergic beta-Antagonists; D013566:Sympathomimetics; D011433:Propranolol; D010869:Pindolol