Effect of age on hemodynamic and metabolic response to static exercise.

Static muscle exercise tests consisting of one-third maximum voluntary contraction of the forearm for 5 min was carried out in a group of older (mean age 46.8 yr) and younger men (mean age 25.3 yr). The mean hemodynamic changes in the two groups were quite comparable with increases in heart rate (31.3 and 38.4 beats/min), systolic pressure (74.3 and 63.2 mmHg), and diastolic pressure (58.1 and 47.3 mmHg) in older and younger groups, respectively. There was a prompt postexercise increase in mean total plasma catecholamine level in older males with a rapid decline over the next 15 min; the increase was due primarily to an elevation of plasma epinephrine. There were increases in plasma free fatty acids and in lactates of equivalent degrees in both groups. The younger men had a greater fall in relative stroke volume and a lesser rise in relative cardiac index than the older group. The results indicate that the adrenomedullary response induced by static exercise may be significantly influenced by age.