Abstract
Whereas experimental studies showed that in healthy trained subjects, the phosphodiesterase-5
inhibitor (PDE-5i) sildenafil improves exercise capacity in hypoxia and not in normoxia,
no studies on the effects of the long half-life PDE-5i tadalafil exist. In order to
evaluate whether tadalafil influences functional parameters and performance during
a maximal exercise test in normoxia, we studied 14 healthy male athletes in a double-blind
cross-over protocol. Each athlete performed two tests on a cycle ergometer, both after
placebo or tadalafil (at therapeutic dose: 20 mg) administration. Oxygen consumption
(V·O2 ), blood lactate, respiratory exchange ratio, rate of perceived exertion, arterial
blood pressure (BP), heart frequency (HR) and oxygen pulse (V·O2 /HR) were evaluated before exercise, at individual ventilatory and anaerobic thresholds
(IVT and IAT), at V·O2max and during recovery. Compared to placebo, a single tadalafil administration significantly
reduced systolic BP before and after exercise (p < 0.05), decreased V·O2 /HR at IVT (13.3 ± 1.8 vs. 14.5 ± 2.1 mL · beat-1 ; p = 0.03), but did not modify individual V·O2max , IVT, or IAT. In healthy athletes, 20 mg of tadalafil does not substantially influence
physical fitness-related parameters, exercise tolerance, and cardiopulmonary responses
to maximal exercise in normoxia; it remains to be verified if higher doses/prolonged
use influence health and/or sport performance in field conditions.
Key words
erectile dysfunction - sport - nitric oxide - doping - exercise - PDE‐5
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luigi.diluigi@iusm.it
