The effect of participation in a regular exercise program upon aerobic capacity during pregnancy

This study examined the questions of whether pregnancy decreases physical fitness, as measured by maximal oxygen consumption, between the second and third trimesters, and whether maintaining a regular exercise program during the second half of pregnancy affects fitness. At the beginning of their second trimester, pregnant women were randomly assigned to either a nonexercising control group or an exercising group. They completed a maximal progressive exercise test on a cycle ergometer at 20 and 30 weeks, during which pulmonary parameters of aerobic capacity were measured. The exercising group demonstrated greater improvement in aerobic capacity than did the control group, manifested by increases in tidal volume and oxygen consumption and a stable ventilatory equivalent for oxygen. Pregnancy did not reduce maximal oxygen consumption between the second and third trimesters of pregnancy.