Cardiac output and stroke volume in swimming harbor seals

Ponganis, PJ, Kooyman GL, Zornow MH, Castellini MA, Croll DA.  1990.  Cardiac output and stroke volume in swimming harbor seals. Journal of Comparative Physiology B-Biochemical Systemic and Environmental Physiology. 160:473-482.


breath-hold, diving seal, heart-rate, mammalian respiratory system, metabolism, myocardial blood-flow, percutaneous, phoca-vitulina, pulmonary artery, thermodilution, weddell seals


Cardiac output was measured by the thermodilution method in three young harbor seals, at rest and while swimming up to the maximum effort for which they could be trained. Stroke volume was determined by counting heart rate simultaneously with determination of cardiac output. Cardiac outputs varied widely between surface breathing (7.8 and breath-holding while swimming under water (1.8 Stroke volume while at the surface was almost twice the volume while submerged. Surface cardiac output was always near maximal despite work effort, whereas submerged cardiac output gradually increased at higher work efforts. The cardiovascular performance of seals at the maximum MO2 we could induce from them is equivalent to that of the domestic goat.