The marine mammal dive response is exercise modulated to maximize aerobic dive duration

摘要: When aquatically adapted mammals and birds swim submerged, they exhibit a dive response in which breathing ceases, heart rate slows, blood flow to peripheral tissues organs is reduced. The most intense occurs during forced submersion conserves oxygen for the brain heart, thereby preventing asphyxiation. In free-diving animals, less profound, energy metabolism remains aerobic. However, even this relatively moderate bradycardia seems diametrically opposed normal cardiovascular (i.e., tachycardia vasodilation) physical exertion. As result, there has been long-standing paradox regarding how aquatic exercise while submerged. We hypothesized based on modeling that must increase ensure adequate delivery active muscles. Here, we show (HR) does indeed with flipper or fluke stroke frequency (SF) voluntary, aerobic dives Weddell seals (HR = 1.48SF − 8.87) bottlenose dolphins (HR = 0.99SF + 2.46), respectively, two marine mammal species different evolutionary lineages. These results support our hypothesis maintain muscle swimming submerged by combining elements of both responses, one other predominating depending level