V̇O_2peak prediction and exercise prescription for pregnant women

Purpose: The present study was designed to develop and validate a prediction equation for peak oxygen consumption (V̇O_2peak) using a progressive treadmill test and to refine the current target HR exercise guidelines for pregnancy (PARmed-X for Pregnancy). Methods: One hundred fifty-six women between 16 and 22 wk of gestation performed the test to volitional fatigue (peak exercise test). Data from every fourth subject were used to form the cross-validation group. The women were separated into two age groups; 20-29 (N = 60) and 30-39 (N = 96) yr of age and then further separated into fit (V̇O_2peak at the top 25th percentile), unfit (V̇O_2peak at the bottom 25th percentile), and active (between these two ranges). HR and V̇O_2peak values were used in the regression equation to predict target HR ranges at 60 and 80% V̇O _2peak. Results: The prediction equation (R² = 0.72, R ²_adjusted = 0.71 and SEE = 2.7) was compared with cross validation (N = 39; P = 0.78). Fit women had a V̇O_2peak ≥ 27.2 mL·kg^-1·min^-1 and ≥ 26.1 mL·kg^-1·min^-1 for ages 20-29 and 30-39 yr, respectively, representing the top 25th percentile. Unfit women had a V̇O_2peak of ≤ 21.0 mL·kg^-1·min ^-1 and ≤ 19.6 mL· kg^-1·min^-1, respectively, representing the bottom 25th percentile. HR/V̇O _2peak regression lines for each fitness level were used to generate the target HR zones in each age group. Conclusion: This is the first study to provide a validated prediction equation of V̇O_2peak 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.