MATERNAL AND FETAL RESPONSES TO LOW-IMPACT AEROBIC DANCE

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 lo w-impact aerobic dance. The maternal and fetal responses were then com pared to 40 minutes of walking at the same heart rate, The aerobics pr ogram consisted of a 10-minute warm-up, 20 minutes of high-intensity e xercise, and 10 minutes of decreasing intensity. Heart rates were reco rded every 5 minutes, and oxygen uptake (VO2) and fetal response (real -time ultrasound) were obtained every 10 minutes. The maternal heart r ates were similar during both trials (overall, 133 +/- 6 beat/min). VO 2 values during walking were about 4 ml/kg/min greater than during aer obic dance (p less than or equal to 0.003). Minute ventilation (V-E) w as also greater during walking (28.7 +/- 6.4 versus 24.1 +/- 3.4 L/min , p less than or equal to 0.001). Respiratory exchange ratios and the ventilatory equivalents for oxygen (V-E/VO2) were similar for both tri als. Aerobic dance caused greater fetal heart rates than walking (p le ss than or equal to 0.001), differences being as high as 25 beat/min. The fetal rates had returned toward rest within 5 minutes following ex ercise. Low-impact aerobic dance, compared with walking at similar hea rt rates, results in a lower maternal metabolic rate and increases the transient stress on the fetus.