Our purpose was to determine if pregnancy alters the cardiovascular response to exercise. Thirty-nine women [29 ± 4 (SD) yr], performed submaximal and maximal exercise cycle ergometry during pregnancy (antepartum, AP, 26 ± 3 wk of gestation) and postpartum (PP, 8 ± 2 wk). Neither maximal O2 uptake (V̇O(2max)) nor maximal heart rate (HR) was different AP and PP (V̇O2 = 1.91 ± 0.32 and 1.83 ± 0.31 l/min; HR = 182 ± 8 and 184 ± 7 beats/min, P>0.05 for both). Cardiac output (Q̇, acetylene rebreathing technique) averaged 2.2 to 2.8 l/min higher AP (P<0.01) at rest and at each exercise work load. Increases in both HR and stroke volume (SV) contributed to the elevated Q̇ at the lower exercise work loads, whereas an increased SV was primarily responsible for the higher Q̇ at higher levels. The slope of the Q̇ vs. V̇(O2) relationship was not different AP and PP (6.15 ± 1.32 and 6.18 ± 1.34 l/min Q̇/l/min V̇(O2), P>0.05). In contrast, the arteriovenous O2 difference (a-vO2 difference) was lower at each exercise work load AP, suggesting that the higher Q̇ AP was distributed to nonexercising vascular beds. We conclude that Q̇ is greater and a-vO2 difference is less at all levels of exercise in pregnant subjects than in the same women postpartum but that the coupling of the increase in Q̇ to the increase in systemic O2 demand (V̇(O2)) is not different. These data suggest that the perfusion of exercising muscle is unchanged during pregnancy and that the major hemodynamic change is an augmented Q̇ so that blood flow to the uterus and fetus is not compromised.
|Original language||English (US)|
|Number of pages||6|
|Journal||Journal of Applied Physiology|
|State||Published - 1989|
ASJC Scopus subject areas
- Orthopedics and Sports Medicine
- Physical Therapy, Sports Therapy and Rehabilitation