The benefits of a high-intensity aquatic exercise program (HydrOS) for bone metabolism and bone mass of postmenopausal women

This study aimed to evaluate the 24-week effects of a high-intensity aquatic exercise program on bone remodeling markers and bone mass of postmenopausal women. In this randomized, controlled trial we studied 108 women (58.8 ± 6.4 years), randomized into Aquatic Exercise Group (AEG), n = 64, performing 24 weeks of aquatic exercises, and Control Group (CG), n = 44, sedentary. They had their fasting morning blood sample collected for the measures of intact parathyroid hormone (iPTH), procollagen type 1 amino-terminal propeptide (P1NP) and carboxy-terminal cross-linking telopeptide of type I collagen (CTx). Bone mass was measured by dual-energy X-ray absorptiometry before and after the intervention. Participants of both groups received a daily supplementation of 500 mg of elementary calcium and 1,000 IU of vitamin D (cholecalciferol). Results showed an augment in bone formation marker (P1NP) only in the AEG (15.8 %; p = 0.001), and although both groups experienced significant enhancements in bone resorption marker (CTx), this increase was less considerable in the AEG (15 % in the AEG and 29 % in the CG). IPTH was increased by 19 % in the CG (p = 0.003) at the end. The femoral trochanter BMD presented a 1.2 % reduction in the CG (p = 0.009), whereas in the AEG no change was observed (p = 0.069). The proposed aquatic exercise program was efficient in attenuating bone resorption raise and enhancing bone formation, which prevented the participants in the AEG from reducing the femoral trochanter BMD, as happened in the CG.