Aortic Reservoir Function of Lifelong Japanese Female Pearl Divers

Abstract

PURPOSE: Female pearl divers in Japan, called “Ama”, perform repeated breath-hold free-diving for collecting pearls in oysters, seaweeds, and shellfish in the cold sea. In a typical day, they dive 50-200 times, 4-6 days/week throughout the year. We have previously reported significantly lower systemic arterial stiffness values in Ama compared with the age-matched sedentary peers living in the same fishing villages. As a follow-up study, the primary aim of the present study was to evaluate their aortic reservoir function and segmental arterial stiffness. METHODS: We recruited 115 female pearl divers (mean age: 65±11 yr) as well as age-matched 50 physically inactive and 33 physically active female non-divers living in the same fishing villages in rural locations. Aortic reservoir and excess pressure were calculated from the synthesized aortic pressure waveforms derived from carotid arterial pressure waveforms obtained with arterial applanation tonometry. Pulse wave velocity from the heart to the brachial artery (hbPWV; partly reflecting proximal aortic stiffness) and between the brachial artery and the ankle (baPWV; reflecting stiffness of abdominal aorta and leg arteries) were measured. RESULTS: There were no significant differences in age, body weight, and body mass index among the groups. Blood pressure and pulse pressure in the brachial artery and the aorta were not different among the groups. Aortic reservoir function, as measured by the normalized area under the curve of aortic reservoir pressure by area under the curve of aortic blood pressure, tended to be higher in physically active individuals (P=0.06) and significantly greater in Ama (P<0.05) compared with their sedentary peers. baPWV was 8-9%lower in Ama and physically active adults than in sedentary adults (P<0.05 for both). hbPWV was 5% lower in physically active adults and 9% lower in Ama compared with their sedentary peers (P<0.05). CONCLUSIONS: Our present findings suggest that life-long repetitions of breath-hold diving are associated with proximal aortic destiffening and improved aortic reservoir function.