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

Abstract

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-yr group: n = 23, 53 ± 9 yr; ≥65-yr group: n = 38, 72 ± 4 yr, representing middle-aged and older groups, respectively) and 94 female nondivers (<65-yr group: n = 48, 53 ± 9 yr; ≥65-yr group: n = 46, 73 ± 5 yr) were studied. Aortic pressure was estimated from applanation tonometry of carotid arterial pressure waveforms via a 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 nondivers, 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 pearl divers than in nondivers (main effect of group, P < 0.01). Therefore, compared with female nondivers, lifelong female pearl divers may have lower central arterial stiffness that enhances diastolic aortic pressure, thereby preserving greater carotid blood flow during diastole.NEW & NOTEWORTHY This study indicated that, compared with female nondivers, lifelong female pearl divers exhibited higher diastolic carotid blood flow alongside higher aortic pressure during diastole. Therefore, lifelong repeated diving exposure may lead to decreased arterial stiffness, which can facilitate higher diastolic aortic pressure and thereby enhance distal arterial blood flow during diastole.