Acute responses to structured aerobic and resistance exercise in women with gestational diabetes mellitus

Research on the acute responses to exercise in pregnancy is scarce, especially for women affected by gestational diabetes mellitus (GDM). The aim of this study was to investigate responses to a single bout of exercise performed multiple times throughout the pregnancy in women diagnosed with GDM. Data from 18 pregnant women (aged: 32.8 ± 3.8) diagnosed with GDM, treated with diet only, were analyzed. Participants' pre-pregnancy body mass index was 24.4 ± 4.9 kg/m² , 50% of them were nulliparous, and 50% of the sample regularly exercised before the pregnancy. The exercise intervention consisted of an individual structured aerobic and resistance exercise program performed twice per week from the time of diagnosis until at least the 36th week of pregnancy. The exercise program included 20 minutes of aerobic exercise, 20-25 minutes of resistance exercise, and 10 minutes of cool down. Maternal heart rate, systolic and diastolic blood pressure, temperature and fetal heart rate were measured at every exercise session, along with blood glucose on 3 occasions. In total, 365 exercise sessions were analyzed (85 in the second trimester and 280 in the third trimester), on average 20.3 ± 7.7 per participant. Heart rate and fetal heart rate were elevated during both the aerobic and resistance parts of the exercise session (P < .01) in comparison with the baseline while systolic and diastolic blood pressure did not change in the total sample. There was a slight elevation in tympanic membrane temperature during the aerobic part of the session (P < .01). All parameters returned to baseline levels by the end of the session. Glucose levels dropped from the baseline, from 4.7 ± 0.6 to 3.9 ± 0.4 mmol/L (P < .01). There were no differences in responses to exercise between the second and third trimesters, nor between pre-pregnancy exercisers and non-exercisers. The combination of aerobic and resistance exercise for women diagnosed with GDM does not have harmful short-term effects if performed according to guidelines. Likewise, exercise can be considered useful for controlling hyperglycemia in pregnancy for women affected by GDM.