This is the first study to provide a validated prediction equation of VO2peak for pregnant women using a progressive treadmill exercise test. The defined target HR zones based on age and the appropriate fitness levels can be used for exercise prescription in healthy pregnant women.

We examined the physiological and metabolic responses of 24 active late pregnant women to 40 min of vigorous (95% ventilatory threshold) steady-state treadmill exercise followed by a metabolic perturbation [oral glucose tolerance test (OGTT), 75 g] after exercise. Heart rate and respiratory measures were taken throughout exercise, and blood samples were collected during exercise and every 30 min during the 2-h OGTT. Values were compared with those for a group of physically active nonpregnant women (n = 16) in the luteal phase of the menstrual cycle. Although late pregnant women were heavier, they performed the same work rate (182 vs. 208 W, P > 0.05), with the same oxygen pulse, but responded to the exercise with a blunted heart rate and relative oxygen consumption, with less carbon dioxide expired, possibly due to pregnancy-related adaptations in heart efficiency. Resting glucose concentrations were the same between groups, but by 40 min of exercise (3.8 ± 0.1 vs. 4.6 ± 0.1 mmol/l) and into 15 min of recovery (4.3 ± 0.2 vs. 5.0 ± 0.1 mmol/l), glucose concentrations were diminished in late pregnant women (P ≤ 0.05, respectively). The pregnancy-induced delay of glucose uptake was seen in response to the postexercise OGTT compared with the nonpregnant women, but insulin sensitivity (ISI) remained (7.4 ± 0.9 vs. 9.7 ± 1.4 ISI, P > 0.05, respectively), with the preservation of the sensitivity of lipolysis inhibition of nonesterified free fatty acids to insulin. These adaptations may be fetoprotective, because our research suggests that 40 min of continuous treadmill exercise is well tolerated by physically active pregnant women. No adverse effects on birth outcome (3.53 ± 0.08 kg birth weight; 39.6 ± 0.33 wk gestational age) were observed.

This feasibility study investigated the response of maternal heart rate, blood pressure, and uterine contractions to a 30-min bed-rest exercise session (while listening to music) in hospitalized women with varying diagnoses of high-risk pregnancy. Eleven antenatal women who were hospitalized for activity restriction were assigned randomly to either a bed-rest exercise and music group (n = 6) or a bed-rest and music group (n = 5) that involved no exercise. The key findings were that there were no changes in maternal blood pressure or in the number of uterine contractions following the exercise intervention. A supervised bed-rest exercise intervention may, therefore, provide minimal risks and help alleviate the physiological effects of hospital activity restriction.

Considering the maternal risk for both short-and long-term disability imposed by activity restriction, it is of great concern that the antepartum symptoms of bed rest are still evident in the postpartum period. The benefits of bed-rest-exercise may alleviate or even prevent physiological distresses or deconditioning associated with activity restriction, thus, eliminating or stabilizing, factors that may augment existing complications. This is the first study to investigate the feasibility of incorporating a bed-rest exercise program in a specific hospitalized twin pregnancy case. The maternal physiological responses of heart rate, blood pressure and uterine contractions to a four week bed-rest resistance program were measured in a woman hospitalized due to complications during her twin pregnancy. A second participant (same diagnoses) was included as a control. The bedrest-exercise reduced the degree of swelling in the lower extremities, promoted more energy during the day and a better night's sleep. There were no significant differences in uterine contractions pre vs post protocol and all babies were born healthy.