Moderate intensity swimming training on bone mineral density preservation under food restriction in female rats

Taciane Maria Melges Pejon,Victor Fabrício,Wladimir Rafael Beck,Claudio Alexandre Gobatto

doi:10.1590/s1980-6574202000040062

Abstract

Abstract Aim: To investigate the effect of moderate-intensity swimming training on bone mineral density under a 20% food restriction (FR) schedule for 12 weeks in female rats. Methods: Forty female Wistar rats were distributed into four groups: control (CG), exercised (EG), food restriction (FRG), and food restriction/exercised (FREG). At 95 days, the animals were subjected to aquatic adaptation and then performed the critical load test to individually determine the critical load intensity (CLi, % of body mass). Exercised groups swam 5 days a week, 30 minutes daily with weekly adjustment of the load equivalent to 80% of the CLi. The FR schedule was 20% in relation to CG and started concomitantly with physical training (PT). After 12 weeks, visceral fat weight was recorded and the femur was collected for biophysical and biomechanical analysis. Results: FR and exercise training promoted visceral fat reduction (p<0.01). FR reduced bone mineral density (p<0.01), while exercise training prevented such reduction. On the other hand, FR and exercise training did not promote significant changes in biomechanical parameters of the femur. Conclusion: Exercise training at moderate intensity was efficient in preserving bone mineral density despite long term of FR at 20%.

Highlights

A high amount of adipose tissue has been associated with metabolic disorders[1], such as obesity[2,3], diabetes[4,5], and cardiovascular diseases[6]
food restriction (FR) has been associated with bone mineral density (BMD) impairment[8,9] once indirectly induces mechanisms leading to greater osteoclastic action[10,11], due to hormonal changes and mineral and protein distribution[10]
The animals arrived at the bioterium with 45 days old to familiarize with the environment and were randomly distributed into four groups: control group (CG: n=10), food restriction group (FRG: n=10), exercised group (EG: n=9), and food restriction/exercised training group (FREG: n=11), containing a maximum of 5 animals per cage

Summary

Introduction

A high amount of adipose tissue has been associated with metabolic disorders[1], such as obesity[2,3], diabetes[4,5], and cardiovascular diseases[6]. FR has been associated with bone mineral density (BMD) impairment[8,9] once indirectly induces mechanisms leading to greater osteoclastic action[10,11], due to hormonal changes and mineral and protein distribution[10]. These alterations increase the risk of fractures[8,9] and diseases related to bone health[9] in both genders, but females seem to be more affected, especially those older, characterized by the reduction of steroid hormones that act on bone balance[12]. The exercise prescription for such populations must employ an optimized relationship between intensity and volume, besides preoccupation with the type of exercise

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Results

Conclusion