Effects of oral propranolol and exercise protocol on indices of aerobic function in normal man.

The exercise responses to two different progressive, upright cycle ergometer tests were studied in nine healthy, young subjects either with no drug (ND) or following 48 h of oral propranolol (P) (40 mg q.i.d.). The ergometer tests increased work rate by 30 W either every 30 s or every 4 min. Propranolol caused a significant (p < 0.05) reduction in peak oxygen uptake ( during both the 30-s and 4-min tests (30-s ND, 3949 ± 718 mL∙min−1; 30-s P, 3408 ± 778 mL∙min−1; 4-min ND, 4058 ± 409 mL∙min−1; 4-min P, 3725 ± 573 mL∙min−1). There was no difference between 30-s ND and 4-min ND for peak . The ventilatory anaerobic threshold was not significantly different between any test (30-s ND, 2337 ± 434 mL O2∙min−1; 30-s P, 2174 ± 406 mL O2∙min−1; 4-min ND, 2433 ± 685 mL O2∙min−1; 4-min P, 2296 ± 604 mL O2∙min−1). The at which blood lactate had increased by 0.5 mM above resting levels was significantly lower than the ventilatory anaerobic threshold for the 4-min ND (1917 ± 489) and the 4-min P (1978 ± 412) tests, but ...