Respiratory sinus arrhythmia and submersion bradycardia in bottlenose dolphins (Tursiops truncatus).

摘要: Among the many factors that influence cardiovascular adjustments of marine mammals is act respiration at surface, which facilitates rapid gas exchange and tissue re-perfusion between dives. We measured heart rate (f H) in six, adult male bottlenose dolphins (Tursiops truncatus) spontaneously breathing surface to quantify relationship f H, compared this H during submerged breath-holds. found exhibit a pronounced respiratory sinus arrhythmia (RSA) resulting increase after breath followed by gradual decrease over following 15-20 seconds steady maintained until breath. RSA resulted maximum instantaneous (if 87.4±13.6 beats min-1, minimum if 56.8±14.8 degree was positively correlated with inter-breath interval (IBI). The 2-minute, breath-holds where exhibited submersion bradycardia (36.4±9.0 min-1) lower than observed an average IBI, however IBIs longer 30 seconds, (38.7±10.6 not significantly different from 2-minute These results demonstrate patterns are similar those extended IBI. Here we highlight importance influencing variability emphasize need understand its bradycardia.