BONE MASS DENSITY AND CARDIORESPIRATORY FITNESS AMONG 30 ~ 59-Y WOMEN

Abstract

PURPOSE: Bone mass density(BMD) and cardiorespiratory endurance(CRF) are main markers of physical fitness and wellness. This study aims to explore the relationship between BMD and CRF among 30 ~ 59-y women, and the role of Estradiol (E2) and osteocalcin (BGP). METHODS: 226 healthy women age 30 to 59 y participated. BMD of total and various parts of the body were measured by DEXA (GE company). All participants conducted symptom restricted exercise load test with Bicycle ergometer (cortex custo ec300). Serum E2 and BGP were measured using Radioimmunoasssay (DSL). F-test, Correlation and Linear regression methods were used (SPSS 15.0). RESULTS: The concentration of BGP was positively correlated with exercise termination load and time (r1 = 0.296, r2 = 0.309, P < 0.05); There is a significant positive correlation between serum E2 and exercise termination load, termination heart rate and time (r1 = 0.300, r2 = 0.305, r3 = 0.290, P < 0.05). But those correlations are no longer significant after adjusting for age. There is a significant correlation between BMD of thigh, trunk, pelvis and whole body and exercise termination load (r = 0.304, 0.319, 0.303, 0.330, P < 0.05) after age adjusted. The regression equation between exercise termination load intensity and whole-body BMD Z score is y = 99.350 + 8.619x (R = 0.320, R2 = 0.103). There is a significant positive correlation between Z-score of whole-body BMD and exercise termination load. The participants were divided into three groups with low (the lowest 20%, Z-Score ≤ - 0.6), medium (middle 40% Z-Score : - 0.6 ~ 0.6) and high (the highest 40%, Z-score ≥ - 0.6) BMD, and the age of each group was balanced. There is significant difference in exercise termination load between different BMD groups (88.6 ± 20.5, 99.1 ± 22.0 and 110.7 ± 21.3 W respectively, F = 3.287, P = 0.046). CONCLUSIONS: The changes of body composition are related to cardiopulmonary function, especially BMD is positively correlated with CRF. The relationship between E2 level and exercise ability could be mainly attributed to the age change. Improving body composition, especially maintaining BMD through lifestyle intervention is of great significance to women’s cardiovascular health. This Study was Suppoted by the National Science and Technology Key Project 2018YFC2000600