"Relationship between stress hormones and testosterone with prolonged endurance exercise." http://www.ncbi.nlm.nih.gov/pubmed/15618989 http://www.ncbi.nlm.nih.g

"Relationship between stress hormones and testosterone with prolonged endurance exercise." http://www.ncbi.nlm.nih.gov/pubmed/15618989 http://www.ncbi.nlm.nih.gov/pubmed/15618989 More importantly: looking in the mirror. Even though I'm older, I'm leaner now doing zero steady-state cardio than I ever was running/biking dozens of miles a week.