# The Effect of Regular Physical Activity on Muscle and Adipose Tissue in Premenopausal Women
###### Abstract  
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 \(\pm\) 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. physical activity; body composition; whole body analysis; segmental analysis; apendicular index; weight status +
Footnote †: journal:a regular loss of FFM and, thus, muscle mass of 0.34-1.28% per year, starting at the age of 30 [7]. This reduction rapidly increases in women about two years before their final menstrual period (FMP) [3]. Muscles infiltrated with fat tissue inhibit the muscle cross-section from corresponding with their produced strength [4]. Such changes can lead to an early stage of sarcopenia. Sarcoma is a serious muscle disease, characterized by low levels of three parameters: muscle strength, quality/quantity of muscle tissue, and physical performance [8]. Sarcoma limits everyday function and contributes to invalidity, decreasing one's independence and self-reliance [9; 10]. The risk of sarcopenia increases with age, and it is most prevalent in individuals 60+ years of age [11; 12]. Nonetheless, study data from [PERSON] et al. [13] illustrated a prevalence in women younger than 60 of 1.6-15.6%, depending on age and the diagnostic criteria used. Considering that an early diagnosis of sarcopenia is essential for successful treatment [14], it is important to gather data on the quality of muscle tissue and the level of physical activity of women approaching menopause. Evidence indicates that sarcopenia can be prevented, delayed, or even reversed with suitable intervention of exercise [15]. One of the options for assessing sarcopenia is using body composition to calculate the appendicular index, based on the DXA measurement [16]. Regular physical activity (PA) is important in the prevention of many noninfectious chronic diseases, such as cardiovascular diseases, cancer, type 2 diabetes, obesity, bone health degradation, and increased disability. Physical activity is a fundamental life need and its lack influences the individual's basic morphology, state of health, well-being, and physical performance [17; 18; 19]. Importantly, PA is a modifiable, controllable parameter that considerably influences the individual's condition [20]. In contrast, physical inactivity, in combination with inappropriate nutrition and increased stress, increases the risk of occurrence of the abovementioned diseases. There is strong research evidence that a sedentary lifestyle is more common in obese individuals than in individuals with normal weight [21]. Middle-aged women should follow the recommendations of WHO for PA, designed for a healthy adult population (18-64 years old). The recommendation is for a minimum of 150 min of moderate-intensity aerobic PA, or at least a minimum of 75 min of vigorous-intensity aerobic PA per week [22].