Extreme bradycardia and tachycardia in the world’s largest animal
Goldbogen, J.A.; Cade, D.E.; Calambokidis, J.; Czapanskiy, M.F.; Fahlbusch, J.; Friedlaender, A.S.; Gough, W.T.; Kahane-Rapport, S.R.; Savoca, M.S.; Ponganis, K.V.; Ponganis, P.J. (2019). Extreme bradycardia and tachycardia in the world’s largest animal. Proc. Natl. Acad. Sci. U.S.A. 116(50): 25329-25332. https://dx.doi.org/10.1073/pnas.1914273116
In: Proceedings of the National Academy of Sciences of the United States of America. The Academy: Washington, D.C.. ISSN 0027-8424; e-ISSN 1091-6490, meer
|   |
| Trefwoorden |
Bos taurus
Diving
Heart rate
Scaling
Balaenoptera acutorostrata Lacépède, 1804 [WoRMS]; Balaenoptera physalus (Linnaeus, 1758) [WoRMS]
Marien/Kust |
| Author keywords |
cardiac function, blue whale |
| Auteurs | | Top |
- Goldbogen, J.A.
- Cade, D.E.
- Calambokidis, J.
- Czapanskiy, M.F.
|
- Fahlbusch, J.
- Friedlaender, A.S.
- Gough, W.T.
- Kahane-Rapport, S.R.
|
- Savoca, M.S.
- Ponganis, K.V.
- Ponganis, P.J.
|
| Abstract |
The biology of the blue whale has long fascinated physiologists because of the animal’s extreme size. Despite high energetic demands from a large body, low mass-specific metabolic rates are likely powered by low heart rates. Diving bradycardia should slow blood oxygen depletion and enhance dive time available for foraging at depth. However, blue whales exhibit a high-cost feeding mechanism, lunge feeding, whereby large volumes of prey-laden water are intermittently engulfed and filtered during dives. This paradox of such a large, slowly beating heart and the high cost of lunge feeding represents a unique test of our understanding of cardiac function, hemodynamics, and physiological limits to body size. Here, we used an electrocardiogram (ECG)-depth recorder tag to measure blue whale heart rates during foraging dives as deep as 184 m and as long as 16.5 min. Heart rates during dives were typically 4 to 8 beats min−1 (bpm) and as low as 2 bpm, while after-dive surface heart rates were 25 to 37 bpm, near the estimated maximum heart rate possible. Despite extreme bradycardia, we recorded a 2.5-fold increase above diving heart rate minima during the powered ascent phase of feeding lunges followed by a gradual decrease of heart rate during the prolonged glide as engulfed water is filtered. These heart rate dynamics explain the unique hemodynamic design in rorqual whales consisting of a large-diameter, highly compliant, elastic aortic arch that allows the aorta to accommodate blood ejected by the heart and maintain blood flow during the long and variable pauses between heartbeats. |
|
