In this talk, I will review the links and opportunities between the concepts of optimality and regulation in biological systems. 
These concepts have been succesfully applied by a number of researchers to explain dynamics at the cellular level, or the structures of physiological systems.  After an overview of the main conceptual developments, I will address how modern optimal control theory can be used to rationalize regulation mechanisms found in living systems, and how this can be exploited in systems medicine. In addition, I will also discuss some opportunities that optimal control theory offers to modify disease states.