Beta‐adrenergic blockade and training in healthy men—effects on central circulation

Publisher Website
Google Scholar
Abstract
The effect of chronic β‐adrenergic blockade on central circulatory adaptations to physical training was investigated. 16 healthy sedentary males (20–31 yrs) trained on cycle ergometers 40 min/day, 4 days a week for 8 weeks at a work load that during the last 5 weeks corresponded to 75% of the pretraining VO2max. In a single blind way, 8 subjects were during the training period treated with the β‐adrenergic receptor blocker propranolol (160 mg/day), while the remaining 8 received placebo tablets. Pretraining tests were performed before the start of medication and posttraining tests were performed 6 days after the last day of training and medication. The training program resulted in a similar increase (8%) in VO2max in both groups (pppp2/HR) increased in both groups at 120 W (+6%;pp<0.05). The estimated stroke volume at 120 and 180 W, as determined by impedance cardiography, did not change significantly with training although there was a tendency towards an increase in the placebo group only. The resting left ventricular wall thickness and diameter, as determined by echocardiography, did not change significantly with training in either group.—In conclusion, the present study indicates that a moderate degree of β‐adrenergic blockade does not prevent or impair the training‐induced increase in the maximal oxygen uptake. During submaximal work, however, the circulatory adaptation may be less apparent if training has been performed during partial blockade of the sympathoadrenal system.