Maternal and Fetal Responses to Low-Impact Aerobic Dance

ABSTRACT

The purpose of this study was to compare the physiologic responses to low-impact aerobics using treadmill walking as a control. Ten pregnant women between 21 and 28 weeks of gestation completed 40 minutes of low-impact aerobic dance. The maternal and fetal responses were then compared to 40 minutes of walking at the same heart rate. The aerobics program consisted of a 10-minute warm-up, 20 minutes of high-intensity exercise, and 10 minutes of decreasing intensity. Heart rates were recorded every 5 minutes, and oxygen uptake (V·O₂) and fetal response (real-time ultrasound) were obtained every 10 minutes. The maternal heart rates were similar during both trials (overall, 133 ± 6 beat/min). V·O₂ values during walking were about 4 mL/kg/min greater than during aerobic dance (p = ≤0.003). Minute ventilation (V·E) was also greater during walking (28.7 ± 6.4 versus 24.1 ± 3.4 L/min, p = 0.001). Respiratory exchange ratios and the ventilatory equivalents for oxygen (V·E/V·O₂) were similar for both trials. Aerobic dance caused greater fetal heart rates than walking (p = ≤0.001), differences being as high as 25 beat/min. The fetal rates had returned toward rest within 5 minutes following exercise. Low-impact aerobic dance, compared with walking at similar heart rates, results in a lower maternal metabolic rate and increases the transient stress on the fetus.

Keywords

Oxygen uptake - ventilation - fetal heart rate - exercise