Effects of pregnancy and chronic exercise on respiratory responses to graded exercise. Journal of applied physiology (Bethesda, Md. : 1985) [J Appl Physiol] Journal article

Title	Effects of pregnancy and chronic exercise on respiratory responses to graded exercise.
Author(s)	Wolfe LA, Walker RM, Bonen A, McGrath MJ
Institution	School of Physical and Health Education, Queen's University, Kingston, Ontario, Canada.
Source	J Appl Physiol 1994 May; 76(5):1928-36.
MeSH	Adult Aerobiosis Exercise Exercise Test Female Humans Lactates Lactic Acid Oxygen Consumption Physical Education and Training Pregnancy Pregnancy Outcome Pregnancy Trimester, Second Pregnancy Trimester, Third Progesterone Pulmonary Gas Exchange Respiratory Mechanics
Abstract	Effects of cycle ergometer conditioning (heart rate 143 +/- 2 beats/min, 25 min/session, 3 sessions/wk) during the second and third trimesters of pregnancy were studied in 18 healthy previously sedentary women. A nonexercising control group (n = 9) was also studied. Graded exercise tests were conducted for both groups at approximately 17, 27, and 37 wk of gestation and at 20 wk postpartum. Both groups exhibited augmented ventilatory responses to exercise throughout pregnancy. Significant aerobic conditioning effects observed in the exercised group between entry and third trimester of pregnancy testing included a 17% increase in oxygen pulse at peak exercise, reduction in the respiratory exchange ratio during standard submaximal exercise, and an increase in work rate at the onset of blood lactate accumulation. Onset of blood lactate accumulation did not change significantly in the control group. Respiratory exchange ratio at peak exercise was higher in postpartum tests compared with those conducted in late gestation in both groups. Peak postexercise lactate levels were also significantly lower in second and third trimesters of pregnancy testing compared with postpartum in the control group. This effect appeared to be prevented by physical conditioning in the exercised group. The study results support the hypothesis that moderate aerobic conditioning increases maximal aerobic power and the capacity for sustained submaximal exercise. Chronic exercise also appeared to help to preserve anaerobic working capacity in late gestation.
Language	eng
Pub Type(s)	Journal Article Research Support, Non-U.S. Gov't
PubMed ID	8063652

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