A COMPARISON OF CARDIOPULMONARY ADAPTATIONS TO EXERCISE IN PREGNANCY AT SEA-LEVEL AND ALTITUDE

OBJECTIVE: The purpose of this study was to compare maternal cardiopul monary and fetal responses of lowlander pregnant women in the third tr imester to exercise at sea level and at an altitude of 6000 feet. STUD Y DESIGN: Seven women at 33.86 +/- 1 weeks' gestation performed a symp tom-limited maximal exercise test and a submaximal cardiac output exer cise test at sea level at an altitude of 6000 feet. Cardiopulmonary an d metabolic variables were measured and compared at sea level and alti tude. RESULTS: Maximal oxygen consumption and work levels were limited by short-term altitude exposure. Ventilatory variables were not signi ficantly influenced by altitude exposure. During submaximal exercise n o alteration in exercise efficiency or response was seen for most of t he variables when altitude and sea level data were compared. Both card iac output and stroke volume were elevated at altitude at rest but not during exercise, suggesting a lower reserve for both variables at alt itude. Level of plasma glucose, lactate, norepinephrine, and epinephri ne were not significantly influenced by altitude exposure. Fetal heart rate responses did not differ between the sea level and altitude cond itions. CONCLUSIONS: Lowlander pregnant women in the third trimester h ave some limitations to maximal aerobic capacity but not submaximal ex ercise on short-term altitude exposure. No ominous fetal responses hav e been observed during this study. The results suggest that pregnant w omen may engage in at least brief moderate exercise bouts at moderate altitude without adverse consequences.