TY - JOUR
T1 - Prolonged decrease in cardiac volumes after maximal upright bicycle exercise
AU - Renlund, D. G.
AU - Lakatta, E. G.
AU - Fleg, J. L.
AU - Becker, L. C.
AU - Clulow, J. F.
AU - Weisfeldt, M. L.
AU - Gerstenblith, G.
N1 - Copyright:
Copyright 2020 Elsevier B.V., All rights reserved.
PY - 1987
Y1 - 1987
N2 - Sequential exercise-gated cardiac blood pool scintigrams provide a noninvasive technique for evaluating the effect of therapeutic interventions on cardiac volumes and function only if both exercise periods are equivalent in the absence of an intervention. To assess whether they are indeed equivalent, 14 healthy subjects underwent gated blood pool scintigraphy during two maximal upright exercise periods separated by 60 min without changing position. Although resting cardiac output and blood pressure returned to base-line values 60 min after the first exercise period, mean resting heart rate was markedly higher (89.4 ± 2.7 vs. 66.5 ± 2.5 beats/min, P < 0.001) and upright cardiac volumes lower [39.1 ± 4.9 vs. 56.3 ± 6.0 ml, P < 0.001, for end-systolic volume (ESV) and 112.6 ± 8.0 vs. 144.9 ± 9.0 ml, P < 0.001, for end-diastolic volume (EDV)] than before the first exercise period. These differences persisted during low levels of the subsequent exercise but not at high and maximum work loads. Cardiac volumes and heart rate 60 min after an identical exercise protocol in a second group of 22 subjects who received propranolol, 0.15 mg/kg iv, after their initial exercise, however, were the same as those preexercise. Thus higher sympathetic tone may be responsible for the persistently higher heart rate and decreased cardiac volumes after exercise, and the assumption that cardiac volumes and function are similar during two closely spaced sequential exercise studies is not always valid.
AB - Sequential exercise-gated cardiac blood pool scintigrams provide a noninvasive technique for evaluating the effect of therapeutic interventions on cardiac volumes and function only if both exercise periods are equivalent in the absence of an intervention. To assess whether they are indeed equivalent, 14 healthy subjects underwent gated blood pool scintigraphy during two maximal upright exercise periods separated by 60 min without changing position. Although resting cardiac output and blood pressure returned to base-line values 60 min after the first exercise period, mean resting heart rate was markedly higher (89.4 ± 2.7 vs. 66.5 ± 2.5 beats/min, P < 0.001) and upright cardiac volumes lower [39.1 ± 4.9 vs. 56.3 ± 6.0 ml, P < 0.001, for end-systolic volume (ESV) and 112.6 ± 8.0 vs. 144.9 ± 9.0 ml, P < 0.001, for end-diastolic volume (EDV)] than before the first exercise period. These differences persisted during low levels of the subsequent exercise but not at high and maximum work loads. Cardiac volumes and heart rate 60 min after an identical exercise protocol in a second group of 22 subjects who received propranolol, 0.15 mg/kg iv, after their initial exercise, however, were the same as those preexercise. Thus higher sympathetic tone may be responsible for the persistently higher heart rate and decreased cardiac volumes after exercise, and the assumption that cardiac volumes and function are similar during two closely spaced sequential exercise studies is not always valid.
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U2 - 10.1152/jappl.1987.63.5.1947
DO - 10.1152/jappl.1987.63.5.1947
M3 - Article
C2 - 3693228
AN - SCOPUS:0023567431
SN - 0161-7567
VL - 63
SP - 1947
EP - 1955
JO - Journal of applied physiology
JF - Journal of applied physiology
IS - 5
ER -