Figure 7.

A, group mean effects of blockade of opiate sensitive limb muscle afferents on cardioacceleration and mean arterial blood pressure (MAP) at rest and during the steady state of voluntary rhythmic cycling exercise in healthy humans. Data obtained from Amann et al. (2010a). B, reduced steady state ventilation and CO₂ retention resulting from muscle afferent blockade via intrathecal fentanyl in healthy humans at mild to heavy steady state exercise intensities. Note the persistence of the hypoventilatory response, especially during moderate intensity exercise, despite the presence of increased chemoreceptor stimulation. From Amann et al. (2010a).