Cialis is a second-generation erection-promoting drug that followed in the footsteps of Viagra. It works by increasing nitric oxide production, which increases blood flow to the penis. Viagra increases exercise capacity at high altitude (but not sea level) by reducing blood pressure in the lung circulation.
Italian researchers from the Departments of Endocrinology and Sport Sciences at the University of Rome, led by Luigi Di Luigi, found that a single dose of Cialis administered before a maximum exercise test increased salivary testosterone and cortisol levels by more than 100 percent. Before purchasing a wheelbarrow load of Cialis, consider the limitations of this study. Salivary testosterone and cortisol measurements are notoriously inaccurate. Also, hormone levels often increase during exercise because plasma volume (liquid part of blood) decreases by about 20 percent. No study has found that Cialis or Viagra improved performance at sea level in healthy people. Claims that these drugs improve exercise performance or promote muscle growth are little more than urban legends.