Blood levels of adrenalinee, noradrenaline lactate, and glucose, and heart rate and oxygen intake were examined in nine healthy women (29.3 +/- 2.2 years) during a graduated treadmill exercise. At rest there are no differences in these parameters compared with male subjects. During treadmill exercise, two ranges can be distinguished as in male subjects. A range with a slight increase in adrenaline, noradrenaline, and lactate, corresponding to a predominantly aerobic energy supply, and a range with an eight to ten times higher increase of adrenaline, noradrenaline, and lactate related to an additionally increasing anaerobic energy supply. The transition between the two ranges corresponds approximately to the anaerobic threshold, and occurs as in male subjects at an oxygen intake and heart rate of 70--80% and a catecholamine and lactate concentration of 20--30% of the maximal value. At the same exercise level, adrenaline, and noradrenaline are higher than in male subjects. Differences in the relative oxygen intake or the heart rate are similar. During maximal treadmill exercise adrenalin increased by 1,300%, noradrenaline, 1,500%, lactate 1,100% glucose, 30%, the oxygen intake, 1,000%, and the heart rate by about 200%. During ergometric exercise, as in male subjects there is a direct linear correlation between adrenaline and noradrenaline. A direct linear correlation excists between the catecholamines and lactate or glucose levels. Referring to the catecholamines, the lactate level is lower than in male subjects, corresponding to a limitation of acidosis in females.