Reproducibility of haemodynamic and plasma catecholamine responses to isometric exercise and mental arithmetic in normo- and hyper-tensive subjects.
1. To determine the reproducibility of a mental arithmetic stress test and a handgrip exercise test, we studied the responses of blood pressure, heart rate, forearm blood flow and plasma catecholamines on two occasions, with an interval of at least 1 week, in 24 normotensive and 22 hypertensive subjects. 2. The SE of a single observation of the percentage changes of blood pressure ranged from 3.9 to 9.3% in normotensive subjects and from 3.9 to 7.4% in hypertensive subjects in both tests. For heart rate, these values were 4.9-12.3% in the normotensive subjects and 4.8-5.7% in the hypertensive subjects. However, there was a wide individual scatter of these haemodynamic responses during both tests. The forearm blood flow, only measured during mental arithmetic, had an SE of a single observation of 33.7%. 3. In 10 normotensive subjects the SE of a single observation of the change in plasma noradrenaline was 0.16 nmol/l during handgrip exercise and 0.09 nmol/l during mental arithmetic. The corresponding values for plasma adrenaline were 0.04 and 0.05 nmol/l. 4. In conclusion, although both tests showed a rather low SE of a single observation for the blood pressure and heart rate responses in normo- and hyper-tensive subjects, there was a considerable individual variability. If related to the mean forearm blood flow responses, the SE of a single observation of the forearm blood flow response was of similar magnitude. The limited intra-individual reproducibility of both tests should be borne in mind when interpreting pharmacological intervention studies or studies evaluating sympathoadrenal reactivity in cardiovascular disorders.
Lenders
J
J
Department of Internal Medicine, St Radboud University Hospital, Nijmegen, The Netherlands.
Houben
H
H
van Valderen
R
R
Willemsen
J
J
Thien
T
T
D000293:Adolescent; D000328:Adult; D001794:Blood Pressure; D004837:Epinephrine / Q000097:blood*; D015444:Exercise; D005080:Exercise Test; D005260:Female; D006339:Heart Rate; D006439:Hemodynamics; D006801:Humans; D006973:Hypertension / Q000097:blood / Q000503:physiopathology*; D008297:Male; D008433:Mathematics; D008606:Mental Processes / Q000502:physiology*; D008875:Middle Aged; D009638:Norepinephrine / Q000097:blood*; D012016:Reference Values
D009638:Norepinephrine; D004837:Epinephrine