Exercise responses prior to pregnancy and in the postpartum state.

Increased women in the work force and requirements for maximal employee productivity have necessitated examination of the optimal time for parturients to resume normal activities. This prospective study was designed to determine whether prepregnancy measures of aerobic capacity are regained by 4-8 wk postpartum. Weight, percent body fat, recall energy expenditure, and exercise responses via a stage 1, graded cycle ergometer exercise test were determined in 11 subjects (mean age = 27.56 +/- 2.2) in a postabsorptive state prior to pregnancy and 4-8 wk postpartum. Subject characteristics were compared by the Student's t-test and differences across workloads and time by analysis of variance with repeated measures. Prepregnant weight (mean = 58.80 +/- 7.26 kg) was significantly less (P less than 0.05) than postpartum weight (mean = 62.81 +/- 9.12 kg), and prepregnant energy expenditure (1352 +/- 453 kJ) per day was significantly higher (P less than 0.05) than in the postpartum period (274 +/- 333 kJ). Maximal oxygen uptake was significantly higher (35.2 +/- 0.7 vs 30.5 +/- 2.0 ml.kg-1min-1) in the prepregnant as compared with the postpartum period. Further, heart rate at 125 and 150 W was significantly lower prepregnancy as compared with postpregnancy. Results support a detraining effect in the early postpartum period. Whether this detraining is an inevitable factor associated with pregnancy or whether exercising throughout pregnancy can ameliorate the decline in aerobic capacity postpartum is uncertain.