Physiological and perceptual responses to cycle and treadmill exercise during pregnancy

Med Sci Sports Exerc. 1991 Apr;23(4):470-5.


We compared physiological and perceptual responses to non-weight bearing (cycle) and weight bearing (treadmill) exercise in 16 sedentary women throughout a normal term pregnancy. Subjects were recruited late in the first trimester (less than 13 wk gestation) and were studied at 4 wk intervals throughout pregnancy and 4 wk postpartum (PP). Exercise consisted of four 5 min protocols; two were performed on the cycle (C1 = 50 W; C2 = 75 W) and two on the treadmill (T1 = 66 m.min-1, 2.5% grade; T2 = 66 m.min-1, 12% grade). Measured variables included oxygen consumption (VO2), heart rate (HR), minute ventilation (VE), and ratings of perceived exertion (RPE, 10-point Borg scale). Absolute VO2 (ml.min-1) during cycle exercise increased (P less than 0.001) by 25 wk gestation, while relative VO2 ( during treadmill walking was unchanged through late pregnancy and PP. This suggests that cycle exercise is not a true non-weight bearing exercise within a given group of women throughout gestation. Subjects' VO2max values were estimated at each test interval and found to increase (P less than 0.001) by 25-28 wk gestation. Heart rate and RPE responses to exercise remained constant throughout gestation and decreased (P less than 0.01) PP. Although they did not participate in a regular exercise program, it appears that our subjects experienced a mild aerobic training effect during late pregnancy.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Bicycling*
  • Blood Glucose / analysis
  • Blood Pressure
  • Body Weight
  • Carbon Dioxide / physiology
  • Cholesterol / blood
  • Exercise / physiology*
  • Fatty Acids / blood
  • Female
  • Heart Rate / physiology
  • Humans
  • Labor, Obstetric
  • Oxygen Consumption / physiology
  • Perception
  • Pregnancy / physiology*
  • Pregnancy / psychology
  • Tidal Volume
  • Triglycerides / blood
  • Walking*


  • Blood Glucose
  • Fatty Acids
  • Triglycerides
  • Carbon Dioxide
  • Cholesterol