Research Highlights 6 Fahlman 2019

Dolphins Voluntarily Alter Their Heart Rate and Blood Flow Rate to Avoid the Bends

How do dolphins manage to hold their breath for up to 13 minutes while exercising underwater? New research at the Oceanografic in Valencia, Spain, and Dolphin Quest Oahu in Hawaii indicates that dolphins are able to voluntary alter the heart rate and blood flow during diving. This mechanism allows dolphins to adjust blood flow based on the dive they are planning and adjust flow during the dive when needed. Voluntary adjustment of heart rate has been demonstrated previously in other species, such as the harbor porpoise or sea lion, and a limited ability for such an adjustment has also been shown in elite human athletes. The study concluded that this ability to voluntary alter blood flow as needed during the dive is the key adaptation for how dolphins match demand and supply, and may explain how failure of this mechanism during stress can cause diving related issues such as the bends.


  • Fahlman, A., Miedler, S., Rocho-Levine, J., Jabois, A., Arenarez, J., Marti-Bonmati, L., García-Párraga, D., & Cauture, F. (2019). Re-evaluating the significance of the dive response during voluntary surface apneas in the bottlenose dolphin, Tursiops truncatus. Scientific Reports, 9(1), 8613.

Affiliate Organizations:  Fundación Oceanogràfic de la Comunitat Valenciana, Dolphin Quest Oahu

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