Preserved diastolic carotid blood flow is associated with higher diastolic aortic pressure in lifelong female pearl divers

Higher diastolic aortic pressure is associated with central arterial elastic recoil function and may help preserve peripheral perfusion. Japanese female pearl divers, called “Ama,” exhibit lower arterial stiffness as an adaptation to lifelong repeated diving, but whether this translates into enhanced diastolic blood flow remains unclear. This study investigated aortic and carotid hemodynamic profiles to determine whether female pearl divers demonstrate enhanced diastolic blood flow in association with diastolic aortic pressure. A total of 61 middle-aged and elderly female pearl divers (<65-years group: n=23, 53 ± 9 years; ≥65-years group: n=38, 72 ± 4 years, representing middle-aged and older groups, respectively) and 94 female non-divers (<65-years group: n=48, 53 ± 9 years; ≥65-years group: n=46, 73± 5 years) were studied. Aortic pressure was estimated from applanation tonometry carotid arterial pressure waveforms via general transfer function. Carotid blood flow was calculated from blood velocity and diameter of the common carotid artery. Diastolic aortic pressure-time integral and carotid flow volume were calculated as areas under the waveforms from the dicrotic notch to end-diastole. Compared with non-divers, pearl divers exhibited a higher diastolic aortic pressure-time integral (main effect of group, P<0.01). Moreover, diastolic carotid blood flow volume was also greater in peal divers than in non-divers (main effect of group, P<0.01). Therefore, compared with female non-divers, lifelong female pearl divers may have lower central arterial stiffness that enhances diastolic aortic pressure, thereby preserving greater carotid blood flow during diastole.