The dive response redefined: underwater behavior influences cardiac variability in freely diving dolphins

摘要: A hallmark of the dive response, bradycardia, promotes conservation onboard oxygen stores and enables marine mammals to submerge for prolonged periods. paradox exists when are foraging underwater because activity should promote an elevation in heart rate ( f H) support increased metabolic demands. To assess effect interaction between diving response on H, we integrated interbeat H with behavioral observations adult bottlenose dolphins swimming along coast Bahamas. As expected while resting during submergence (40±6 beats min−1) was significantly lower than at water surface (105±8 min−1). The maximum recorded H,max) 128±7 min−1, occurred post-dive intervals. During submergence, level bradycardia modified by activity. Behaviors such as simple head bobbing depth 40% from submerged levels. Higher rates were observed horizontal depth. Indeed, operated 37–58% their H,max active approached 57–79% anticipatory tachycardia animals glided surface. correlated stroke frequency (range=0–2.5 strokes s−1, r =0.88, N =25 dives) calculated swim speed (range=0–5.4 m dives). We find that rather a static reflex, is modulated behavior exercise predictable manner.