My wakeup HR was 48, indicating my sympathetic nervous system has done it's job in helping me respond to Saturday's speed run and is now slowing down. My parasympathetic nervous system has become dominate and is causing my body functions to return to normal. I could tell, though, that I was still tired. I had no desire to go faster. Tomorrow will be another hour rest run.
When we apply stress to our bodies, our sympathetic nervous system responds and elevates our breathing rate to give more oxygen to our bodies. Our heart rate increases to give more blood. If needed, our sweat glands are activated to cool us off. Our adrenal glands are activated to produce certain hormones to help our bodies handle the stress of running. After we stop running, our sympathetic nervous system slows down, and our parasympathetic nervous system becomes dominate and causes our bodies to recover by returning to normal conditions. Thus, in order to properly manage our running, we need to know the symptoms that tell us we are under stress and the symptoms that tell us when we have recovered from stress.