Changes in plasma concentrations of catecholamines and cortisol were measured before and after static exercise performed by the subject pushing with both legs against a strain-gauge bar. No marked changes in plasma catecholamine were observed but plasma cortisol increased after the subject pushed for 3 min at 50% of maximum force. 2. Holding a 20 kg weight for 5 min in one hand caused a rise in plasma cortisol and in plasma ACTH but no changes in growth hormone were observed.