TY - JOUR
T1 - Effects of physical deconditioning after Intense endurance training on left ventricular dimensions and stroke volume
AU - Martin, Wade H.
AU - Coyle, Edward F.
AU - Bloomfield, Susan A.
AU - Ehsani, Ali A.
PY - 1986/1/1
Y1 - 1986/1/1
N2 - To determine the role of preload in maintaining the enhanced stroke volume of upright exercise-trained endurance athletes after deconditioning, six highly trained subjects undergoing upright and supine bicycle ergometry were characterized before and after 3, 8 and 12 weeks of inactivity that reduced oxygen uptake by 20%. During exercise, oxygen uptake, cardiac output by carbon dioxide rebreathing, cardiac dimensions by M-mode echocardiography, indirect arterial blood pressure and heart rate were studied simultaneously. Two months of inactivity resulted in a reduction in stroke volume, calculated as cardiac output/heart rate, during upright exercise (p < 0.005) without a significant change during supine exercise. A concomitant decrease in the left ventricular end-diastolic dimension from the trained to the deconditioned state was observed in the upright posture (5.1 ± 0.3 versus 4.6 ± 0.3 cm; p = 0.02) but not with recumbency (5.4 ± 0.2 versus 5.1 ± 0.3 cm; p = NS). There was a strong correlation between left ventricular end-diastolic dimension and stroke volume (r > 0.80) in all subjects. No significant changes in percent fractional shortening or left ventricular end-systolic dimension occurred in either position after cessation of training. Estimated left ventricular mass was 20% lower after 3 and 8 weeks of inactivity than when the subjects were conditioned (p < 0.05 for both). Thus, the endurance-trained state for upright exercise is associated with a greater stroke volume during upright exercise because of augmented preload. Despite many years of intense training, inactivity for only a few weeks results in loss of this adaptation in conjunction with regression of left ventricular hypertrophy.
AB - To determine the role of preload in maintaining the enhanced stroke volume of upright exercise-trained endurance athletes after deconditioning, six highly trained subjects undergoing upright and supine bicycle ergometry were characterized before and after 3, 8 and 12 weeks of inactivity that reduced oxygen uptake by 20%. During exercise, oxygen uptake, cardiac output by carbon dioxide rebreathing, cardiac dimensions by M-mode echocardiography, indirect arterial blood pressure and heart rate were studied simultaneously. Two months of inactivity resulted in a reduction in stroke volume, calculated as cardiac output/heart rate, during upright exercise (p < 0.005) without a significant change during supine exercise. A concomitant decrease in the left ventricular end-diastolic dimension from the trained to the deconditioned state was observed in the upright posture (5.1 ± 0.3 versus 4.6 ± 0.3 cm; p = 0.02) but not with recumbency (5.4 ± 0.2 versus 5.1 ± 0.3 cm; p = NS). There was a strong correlation between left ventricular end-diastolic dimension and stroke volume (r > 0.80) in all subjects. No significant changes in percent fractional shortening or left ventricular end-systolic dimension occurred in either position after cessation of training. Estimated left ventricular mass was 20% lower after 3 and 8 weeks of inactivity than when the subjects were conditioned (p < 0.05 for both). Thus, the endurance-trained state for upright exercise is associated with a greater stroke volume during upright exercise because of augmented preload. Despite many years of intense training, inactivity for only a few weeks results in loss of this adaptation in conjunction with regression of left ventricular hypertrophy.
UR - http://www.scopus.com/inward/record.url?scp=0022608159&partnerID=8YFLogxK
U2 - 10.1016/S0735-1097(86)80215-7
DO - 10.1016/S0735-1097(86)80215-7
M3 - Article
C2 - 2937829
AN - SCOPUS:0022608159
VL - 7
SP - 982
EP - 989
JO - Journal of the American College of Cardiology
JF - Journal of the American College of Cardiology
SN - 0735-1097
IS - 5
ER -