Adaptations in beta-adrenergic cardiovascular responses to training in older women.
To determine whether endurance exercise training can alter the beta-adrenergic-stimulated inotropic response in older women, we studied 10 postmenopausal healthy women (65.4 +/- 0.9 yr old) who exercised for 11 mo. Left ventricular (LV) function was evaluated with two-dimensional echocardiography during infusion of isoproterenol after atropine. Maximal O(2) consumption increased 23% in response to training (from 1.35 +/- 0.06 to 1.66 +/- 0.07 l/min; P = 0.004). Training had no effect on baseline LV function, end-diastolic diameter, LV wall thickness, or LV mass. The increase in LV systolic function in response to isoproterenol was unaffected by training. Furthermore, neither the systolic shortening-to-end-systolic wall stress relationship nor the end-systolic wall stress-to-end-systolic diameter relationship during isoproterenol infusion changed with training. We conclude that older postmenopausal women can increase their maximal O(2) consumption with exercise training without eccentric LV hypertrophy or enhancement of beta-adrenergic-mediated LV contractile function. These observations provide an explanation for the finding that maximal cardiac output and stroke volume are not increased in older women in response to training.
Spina
R J
RJ
Division of Geriatrics and Gerontology, Claude D. Pepper Older Americans Independence Center, Washington University School of Medicine, St. Louis, Missouri 63110, USA.
Rashid
S
S
Dávila-Román
V G
VG
Ehsani
A A
AA
D000222:Adaptation, Physiological / Q000502:physiology*; D000318:Adrenergic beta-Agonists / Q000494:pharmacology; D000368:Aged; D000375:Aging / Q000502:physiology*; D001285:Atropine / Q000494:pharmacology; D001794:Blood Pressure / Q000187:drug effects / Q000502:physiology; D002320:Cardiovascular Physiological Phenomena / Q000187:drug effects; D004452:Echocardiography; D005260:Female; D006321:Heart / Q000187:drug effects; D006339:Heart Rate / Q000187:drug effects / Q000502:physiology; D006801:Humans; D007545:Isoproterenol / Q000494:pharmacology; D008875:Middle Aged; D018727:Muscarinic Antagonists / Q000494:pharmacology; D009200:Myocardial Contraction / Q000187:drug effects / Q000502:physiology; D010101:Oxygen Consumption / Q000502:physiology; D010806:Physical Education and Training; D010807:Physical Endurance; D011943:Receptors, Adrenergic, beta / Q000502:physiology*; D016277:Ventricular Function, Left / Q000502:physiology
D000318:Adrenergic beta-Agonists; D018727:Muscarinic Antagonists; D011943:Receptors, Adrenergic, beta; D001285:Atropine; D007545:Isoproterenol