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Ventilatory efficiency during pregnancy: the influence of obesity
Author(s) -
Steinback Craig Douglas,
Davenport Margie H,
Mottola Michelle F
Publication year - 2008
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.22.1_supplement.1233.10
Subject(s) - hyperventilation , medicine , respiratory exchange ratio , ventilation (architecture) , obesity , endocrinology , treadmill , zoology , heart rate , biology , mechanical engineering , blood pressure , engineering
We examined the effect of pregnancy and obesity on ventilatory efficiency at rest and during exercise in women of child‐bearing age. We hypothesized that obesity would have a detrimental effect on ventilatory efficiency compared to the normal weight pregnant and non‐pregnant populations. Forty pregnant women (20 normal weight, PG; and 20 obese, PGOB) between 16 and 20 weeks of gestation and 14 non‐pregnant controls (NP) performed a progressive treadmill test to volitional fatigue. Oxygen consumption (VO 2 ), minute ventilation (V E ) and an index of ventilatory efficiency (V E /VCO 2 ratio) were compared at rest and at peak exercise (PKE). PGOB exhibited a hyperventilation at rest (V E = 14.5±2.5 L/min) compared to PG (12.7±2.7 L/min, P<0.001) and NP (11.5±1.6 L/min, P<0.001) despite a lower VO 2 (P<0.05). Ventilatory efficiency was reduced ( higher V E /VCO 2 ratio ) in obese subjects at rest (4.1±0.7) and at PKE (3.0±0.4) compared to NP (2.3±0.3 and 1.8±0.2 respectively; P<0.001) and PG (2.7±0.3 and 2.1±0.2 respectively; P<0.001). Further, BMI was inversely related to efficiency across all subjects at rest (r 2 =0.83, P<0.001) and at PKE (r 2 =0.72, P<0.001). These data indicate that obesity results in a hyperventilation and decreased ventilatory efficiency that is unrelated to pregnancy. This may have implications for exercise capacity and fetal health during pregnancy. Funded by HSFO, OGS and CIHR.