Effect of aerobic conditioning on the peripheral circulation during chronic beta-adrenergic blockade.
The relation of peripheral circulatory adjustments to exercise training during long-term beta-adrenergic blockade has not been investigated. In 12 healthy men aged 22 to 34 years, blood flow in the calf was evaluated with submaximal exercise before and after a 6 week aerobic conditioning program. During conditioning, six subjects received no drug and six received propranolol, 80 to 120 mg/day in divided doses. Treated and control subjects were studied on entry and at the conclusion of a conditioning program, 72 hours after drug withdrawal in subjects given propranolol. The training was intensive and equivalent in both groups. Control subjects increased maximal oxygen uptake from 47.5 +/- 1.1 to 51.4 +/- 0.4 ml/kg per min (p less than 0.05), whereas those on propranolol did not improve. Immediately after exercise, blood flow in the calf was measured with strain gauge plethysmography after 3 minutes of supine exertion on a cycle ergometer. In control subjects, flow decreased from 15.7 +/- 1.6 to 14.0 +/- 1.4 ml/100 ml per min at 300 kg-m/min of exertion (p less than 0.05) and from 26.5 +/- 3.8 to 21.8 +/- 2.3 ml/100 ml per min at 700 kg-m/min (p less than 0.05). Vascular resistance was unchanged in these subjects at 300 kg-m/min (6.1 +/- 0.8 to 6.7 +/- 1.0 pru) (p = NS), but increased at 700 kg-m/min (4.2 +/- 0.8 to 4.8 +/- 0.7 pru) (p less than 0.05). In subjects given propranolol, no change in flow or resistance occurred after training at either work load.(ABSTRACT TRUNCATED AT 250 WORDS)
D000328:Adult; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D007866:Leg / Q000098:blood supply; D008297:Male; D009132:Muscles / Q000098:blood supply* / Q000187:drug effects; D010101:Oxygen Consumption / Q000187:drug effects; D010806:Physical Education and Training; D010991:Plethysmography; D011433:Propranolol / Q000494:pharmacology*; D012039:Regional Blood Flow / Q000187:drug effects; D014655:Vascular Resistance / Q000187:drug effects
D011433:Propranolol