['The serial plasma catecholamine response to exercise has not been studied fully in relation to left ventricular hypertrophy (LVH) in patients with hypertension (HT). This study determined whether plasma catecholamine responses to exercise are altered in essential HT in the presence or absence of LVH.', 'Plasma noradrenaline (NA) and plasma adrenaline (A) were measured at rest, during and after treadmill exercise in 59 hypertensive subjects and 22 age-matched control subjects. Patients were divided into LVH(-) (n = 20) and LVH(+) (n = 39) stratified by left ventricular mass index [LVMI: control subjects, LVH(-), LVH(+): 114 +/- 4, 105 +/- 3, 151 +/- 3 g m-2].', 'Exercise time (9.9 +/- 0.6, 7.6 +/- 0.7, 7.3 +/- 0.6 min) was shorter in patients with HT. Both systolic and diastolic blood pressures were higher in patients with HT, and no difference was observed between LVH(-) and LVH(+) patients. Resting plasma NA was not different (157 +/- 16, 173 +/- 17, 167 +/- 14 pg mL-1), but plasma NA at stage I (300 +/- 30, 342 +/- 40, 469 +/- 40 pg mL-1) was higher in LVH(+) patients than in LVH(-) patients or control subjects. Plasma A response to exercise was similar among the three groups. There was a positive correlation (r = 0.38, P < 0.001) between LVMI and Deltaplasma NA at stage I in all subjects.'] Is hypertensive left ventricular hypertrophy linked to an enhanced catecholamine response to submaximal exercise?