Chemical equilibrium model comprising calcaneus bone mineral density, low-density lipoprotein cholesterol, and physical work capacity in premenopausal women

Background: During menopause, bone density decreases, and low-density lipoprotein cholesterol (LDL-C) rapidly increases; a decrease in the estrogen level is a common factor in these phenomena. Methods: : In this study, we focused on the fact that menopause is a spontaneous process, and aimed to derive the conditions that mitigate the decline in the osteo sono-assessment index (OSI), an index of bone mineral density (BMD), using a chemical equilibrium model. We attempted to establish the relationship between variables related to female hormone secretion (OSI, LDL-C) and a variable related to work capacity (physical work capacity [PWC] at 75% of maximal heart rate) by analogy, using the fact that Gibbs free energy, a thermodynamic variable related to spontaneous change, is related by three variables. Results: : Consequently, if linearity is established between PWC and OSI when LDL-C is used as the standard, then the analogy of chemical equilibrium can be established between the deviation values of these three variables, with equilibrium constant K . Finally, the theoretically determined equilibrium model with constant K was applied to data obtained from the Sports Program Service (SPS) of the Yokohama Sports Medical Center. Conclusions: : The present study suggests that the decrease in bone density could be alleviated by promoting an increase in LDL-C or by mitigating the decrease in PWC. In discussing personal health, mitigating bone density loss and maintaining a high work capacity are important components, which should also take into account the appropriate levels of LDL-C.