HONG KONG: According to a new study by researchers from the University of California revealed that seals and dolphins also experienced irregular heartbeats when doing a deep dive to hunt to for food.
The researchers added that cardiac rhythm complications in both Weddell seals and bottlenose dolphins happens when they hold their breath for a long period of time.
Terrie Williams, a professor of ecology and evolutionary biology and the University of California, Santa Cruz explained that conflicting signals to the heart can lead to cardiac arrhythmias.
“This study changes our understanding of bradycardia in marine mammals,” Williams says. “The heart is receiving conflicting signals when the animals exercise intensely at depth, which often happens when they are starting their ascent. We’re not seeing lethal arrhythmias, but it is putting the heart in an unsteady state that could make it vulnerable to problems.”
During analysis, researchers found out that the heart rates of diving animals varied with both depth and exercise intensity. They said it changes from bradycardia and tachycardia and 70 percent of the time, marine animals suffer from cardiac arrhythmia.
“We tend to think of marine mammals as completely adapted to life in the water. However, in terms of the dive response and heart rate, it’s not a perfect system,” Williams says. “Even 50 million years of evolution hasn’t been able to make that basic mammalian response impervious to problems.”
“This study is not saying that these deep-diving animals will die if they exercise hard at depth,” Williams says. “Rather, it raises questions about what happens physiologically when extreme divers are disturbed during a dive, and it needs further investigation.”
