New evidence indicates that dolphins–and possibly other marine mammals–are able to consciously slow down their heart rates when preparing to dive, and can even adjust their heart rates according to the length of their intended dive. This allows them to conserve oxygen and adjust their body to the changing pressure as they dive, therefore avoiding issues such as ”the bends”. This new discovery is crucial for setting new policies on man-made noise pollution (like underwater blasts) known to cause harm to dolphins and other marine mammals such as ‘the bends’.
Why this new finding is important
Understanding how marine mammals are able to dive safely for long periods of time is crucial to mitigate the health impacts of man-made sound disturbance on marine mammals.
“Man-made sounds, such as underwater blasts during oil exploration, are linked to problems such as “the bends” in these animals. If this ability to regulate heart rate is important to avoid decompression sickness, and sudden exposure to an unusual sound causes this mechanism to fail, we should avoid sudden loud disturbances and instead slowly increase the noise level over time to cause minimal stress. In other words, our research may provide very simple mitigation methods to allow humans and animals to safely share the ocean.”
-Dr. Andreas Fahlman, Fundación Oceanogràfic, Valencia, Spain
Journal Reference: Andreas Fahlman, Bruno Cozzi, Mercy Manley, Sandra Jabas, Marek Malik, Ashley Blawas, Vincent M. Janik. Conditioned Variation in Heart Rate During Static Breath-Holds in the Bottlenose Dolphin (Tursiops truncatus). Frontiers in Physiology, 2020; 11. DOI: 10.3389/fphys.2020.604018