Document Detail

Maximal exercise testing in late gestation: maternal responses.
MedLine Citation:
PMID:  11152921     Owner:  NLM     Status:  MEDLINE    
OBJECTIVE: To study the effects of human pregnancy on metabolic and respiratory responses to maximal cycle ergometer testing and to test the hypothesis that the respiratory exchange ratio at maximal exercise and peak postexercise lactate concentration are lower in the pregnant compared with the nonpregnant state and that these effects are associated with lower excess postexercise oxygen consumption during pregnancy. METHODS: The pregnant (n = 14, mean gestational age 34.7 +/- 0.4 weeks) and nonpregnant control group (n = 14) included healthy, physically active women. Groups were matched for age, height, parity, prepregnant body mass and body mass index (BMI), and aerobic fitness. Breath-by-breath gas exchange was measured at rest, during exercise, and 15 minutes after exercise. The minimum sample size to detect a statistically significant result for a reasonable difference (0.25 L/min) in the ventilatory threshold was calculated to be ten subjects per group; thus, 14 was considered adequate. RESULTS: Maximal oxygen uptake, the ventilatory threshold, the point of respiratory compensation, and calculated work efficiency did not differ significantly between groups. However, the respiratory exchange ratio at maximal exercise, peak postexercise lactate, and excess postexercise oxygen consumption were significantly lower in the pregnant group. Peak lactate was significantly correlated with the respiratory exchange ratio and excess postexercise oxygen consumption. CONCLUSION: The capacity for weight-supported work is preserved in late gestation, and work efficiency is unchanged. However, carbohydrate utilization might be blunted at high levels of exertion. Blunted respiratory responses were attributed to reduced lactate production and/or dilution of lactate in an expanded blood volume.
A P Heenan; L A Wolfe; G A Davies
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, Non-P.H.S.    
Journal Detail:
Title:  Obstetrics and gynecology     Volume:  97     ISSN:  0029-7844     ISO Abbreviation:  Obstet Gynecol     Publication Date:  2001 Jan 
Date Detail:
Created Date:  2001-01-26     Completed Date:  2001-02-22     Revised Date:  2009-10-26    
Medline Journal Info:
Nlm Unique ID:  0401101     Medline TA:  Obstet Gynecol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  127-34     Citation Subset:  AIM; IM    
School of Physical and Health Education, Queen's University, Kingston, Ontario, Canada.
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MeSH Terms
Exercise / physiology*
Exercise Test
Lactic Acid / blood
Oxygen Consumption
Pregnancy / physiology*
Pregnancy Trimester, Third
Pulmonary Gas Exchange
Respiratory Mechanics*
Reg. No./Substance:
50-21-5/Lactic Acid

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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