Impact of pregnancy and obesity on cardiorespiratory responses during weight-bearing exercise

Respir Physiol Neurobiol. 2009 Jul 31;167(3):341-7. doi: 10.1016/j.resp.2009.06.009. Epub 2009 Jun 17.


The present study is the first to compare the cardiorespiratory responses during progressive weight-bearing treadmill exercise in normal-weight non-pregnant (NP, n=14), normal-weight pregnant (PG, n=20) and obese pregnant (PGOB, n=20) women. Exercise duration and peak treadmill speed were lower in PG (23.9+/-4.9 min; 1.6+/-0.2m/s; P<0.001) compared to NP (33.7+/-4.9 min; 2.0+/-0.2m/s) and were further reduced in PGOB (19.6+/-2.8 min; 1.4+/-0.1m/s; P<0.001) indicating a performance limitation to exercise. Ventilation in response to exercise was increased in PG (49.4+/-6.6L/min) compared to NP (39.8+/-5.4 L/min, at 100W; p<0.05) women, and was further augmented by obesity (56.7+/-9.3 L/min, at 100W; p<0.05 versus PG) secondary to an elevated metabolic cost of exercise as indicated by no further increase in .V(E)/.V(CO2) and .V(E)/.V(O2) in PGOB compared to PG women. The normal augmentation of heart rate observed in PG during exercise was not further increased by obesity at standardized sub-maximal work rates.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Anaerobic Threshold / physiology
  • Exercise / physiology*
  • Female
  • Hemodynamics / physiology*
  • Humans
  • Metabolism / physiology
  • Obesity / physiopathology*
  • Pregnancy / physiology*
  • Respiratory Mechanics / physiology*
  • Walking / physiology
  • Weight-Bearing / physiology*