I queried in my last post whether respiratory efficiency increased during pregnancy.
We seem to love studying our furry friends before studying humans… one study looked at the shrew Crocidura russula monacha… so cute!
I digress.. anyway the study found that during pregnancy and lactation, the heart mass is increased while the lung mass is decreased, and there is a 25% higher maximal aerobic capacity. Overall respiratory efficiency is increased from 15% to approximately 30% (ie. it doubles).
Another study (performed in humans) tested the lung function of 50 normal pregnant women at monthly intervals. It found that there were increases in tidal volume, resting minute ventilation, and inspiratory capacity, as well as a small increment in the frequency of respiration. Overall the results suggest that pulmonary function is altered during pregnancy towards a state of greater efficiency.
Trés interesting indeed!
Mover H, Ar A. Heart and lung adaptations to pregnancy and lactation in a crocidurine shrew. Respir Physiol. 1995 Dec;102(2-3):269-78.
Puranik BM, Kaore SB, Kurhade GA, Agrawal SD, Patwardhan SA, Kher JR. A longitudinal study of pulmonary function tests during pregnancy. Indian J Physiol Pharmacol. 1994 Apr;38(2):129-32.