The Effect of Regular Physical Activity on Muscle and Adipose Tissue in Premenopausal Women

Regular physical activity (PA) plays an important role in the prevention of several noninfectious chronic diseases, partly due to its positive effects on body composition. The relationship between the amount of weekly PA and body composition in premenopausal women, however, remains unclear. The objective of the study is to assess the relationship between body composition and the volume of PA in full-time employed premenopausal women. The study included 136 women (aged 41.07 +/- 2.77 years). The women were divided into tertiles (T1-T3) according to the level of total reported weekly PA. T1 were women with the lowest volume of PA, T2 were women with a medium volume, and T3 were women with the highest PA volume. DXA was used to measure body mass (BM), body fat (BF), visceral fat (VFA), and fat-free mass (FFM). For the comparison of means, we used one-way ANOVA and a t test. Practical significance was verified with effect of size. Significant differences were found between women in T1 vs. T2 and T1 vs. T3. When compared with T2, T1 women had a higher BM (+6.10 kg), BF (+5.98 kg), BF (+5.42%), and VF (+17.49 cm(2)). When compared with T3, T1 women had a higher BM (+5.99 kg), BF (+6.42 kg), BF (+5.89%), and VFA (+20.71 cm(2)). We can conclude that a higher volume of weekly PA is associated with lower BF, but appears to have no effect on FFM.

Automated summary

The study found that an increased volume of weekly physical activity is associated with lower body fat in premenopausal women, but appears to have no effect on fat-free mass.