Impact Of Physical Activity On Lean Body Mass, Bone Mineral Density And Adiposity Among Recreationally Active Women And Men

BACKGROUND: It has been well-documented that physical activity can positively improve body composition. Body composition can be affected by the frequency, duration and intensity of the exercises performed. PURPOSE: We assessed how different recreational activities might affect body composition in recreationally active adults. METHOD: In this cross-sectional study, we assessed frequency and duration of physical activity using the 2014 Block Physical Activity Screener. Lean body mass (LBM), bone mineral density (BMD), visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT) were measured using the Lunar iDXA2, MTY dual energy X-ray absorptiometer (DXA). RESULT: A total of 48 recreationally active adults (26 females, 22 males; 51.7 ± 5.7 years of age) were included in the study. Compared to women, men had higher mean total LBM (59.8 ± 6.7 kg vs 39.1 ± 4.1 kg, p = 0.0001), BMD (1.4 ± 5.7 g/cm2 vs 1.2 ± 0.1 g/cm2, p = 0.0001), and VAT volume (799.7 ± 408.0 cm3 vs 408. ± 159.0 cm3, p = 0.0001). However, women had higher SAT volume compared to men (1160.2 ± 449.0 cm3 vs 1014.4 ± 580.1 cm3, p = 0.330), though none of these were significantly different. Participants who walked 1 hour and 30 mins had the lowest SAT volume (752.2 ± 17.6 cm3, p = 0.044). LBM and BMD were significantly highest in participants who ran (56.9 ± 10.4 kg, p = 0.010 and 1.4 ± 0.2 g/cm2, p = 0.023, respectively) and performed weight-bearing exercise 1 to 2 times a week (64.0 kg, p = 0.001; 1.4 ± g/cm2, p = 0.037, respectively). Those who performed fast-paced outdoor walking (r = -0.36, p = 0.006) and weight-bearing exercise (r = -0.328, p = 0.011) were correlated with VAT and SAT volumes, respectively. Those who performed aerobic exercise (r = 0.268; p = 0.033, r = 0.269, p = 0.032), weight-bearing exercise (r = 0.597, p = 0.0001; r = 0.462, p = 0.0001) and fast-paced outdoor walking (r = -0.449, p = 0.001; r = -0.369, p = 0.005) had a significant correlation with LBM and BMD, respectively. CONCLUSION: Our findings suggest that visceral and subcutaneous adiposity may be more modulated by longer duration of physical activity. Running, fast-paced outdoor walking and weight-bearing exercise showed a positive correlation with LBM and a negative correlation with fat mass. Prospective studies should explore the effect of physical activity on body composition in older adults who exercise. Supported by: We would like to acknowledge and thank American Pistachio Growers for funding this study