Metabolic effects of atenolol and doxazosin in healthy volunteers during prolonged physical exercise

Nonselective β-blockers may reduce exercise performance, not only through hemodynamic but also through metabolic effects. During prolonged physical exertion, lipolysis induced by plasma epinephrine occurs through β-adrenoceptors of adipocytes. Therefore, β-blockade may reduce release of free fatty acids (FFA) from adipocytes and consequently the energy supply for muscle cells. In this single-blind study, we compared the metabolic effects of atenolol with those of doxazosin, an α 1 -blocker, during exercise in 26 young volunteers (age 20-35 years). All subjects performed an exercise test on a bicycle ergometer 5 h after consuming a standard breakfast