Maternal and fetal responses to acute high-intensity resistance exercise during pregnancy

Abstract

Objective: To examine maternal and fetal cardiovascular responses to high-intensity resistance exercise in pregnancy.

Methods: 10 healthy pregnant (26.4±3.2 weeks gestation) and 10 healthy non-pregnant individuals were recruited (34.8±6 and 33.5±2.9 years, respectively). At least 48 hours after baseline strength testing to determine 10-repetition maximum (10 RM), participants completed 10 repetitions of barbell back squat, bench press and deadlift at 70%, 80% and 90% of 10 RM with free breathing, followed by 10 repetitions at 90% 10 RM with a Valsalva manoeuvre. Maternal heart rate was monitored continuously. Fetal heart rate, umbilical systolic/diastolic (S/D) ratio, resistive index (RI) and pulsatility index (PI), as well as maternal blood pressure, glucose and lactate were assessed immediately before and after exercise.

Results: The amount of weight lifted and the rate of perceived exertion by pregnant and non-pregnant participants were similar throughout each exercise. Maternal heart rate increased with the amount of weight lifted, peaking with the use of the Valsalva manoeuvre (squat: 137.3±8.4 bpm; bench press: 110.5±10.4 bpm; deadlift: 130.7±9.0 bpm). Fetal bradycardia was not observed, and fetal heart rate did not change from pre-to-post exercise (squat: p=0.639; bench press: p=0.682; deadlift: p=0.847). Umbilical blood flow metrics, such as RI, remained within normal ranges throughout each set of squats (p=0.642), bench press (p=0.287) and deadlifts (p=0.614).

Conclusion: Our findings suggest that high-intensity resistance exercises are well tolerated by both mother and fetus, including while using the Valsalva manoeuvre.

Keywords: Exercises.