Changes in Plasma Concentration of Epinephrine and Norepinephrine With Muscular Work

Summary1. Concentration of epinephrine and norepinephrine has been measured in human plasma after acute and chronic work. 2. Norepinephrine increases markedly with acute muscular work (about 3-fold) and returns to normal within 15-30 minutes after work. 3. Epinephrine response to acute muscular work shows wide variation between individuals, varying from marked rise to no detectable change. Epinephrine values, when elevated, also return to control levels within 15-30 minutes.