TESTOSTERONE AND SHBG RESPONSES TO ACUTE RESISTANCE EXERCISE IN YOUNG HEALTHY WOMEN: EFFECTS OF REGIONAL FAT DISTRIBUTION 1600

Abstract

Regional fat distribution (RFD) has been associated with metabolic derangements in populations with obesity (e.g. upper body fat patterning is associated with higher levels of free testosterone (FT) and lower levels of sex-hormone binding globulin (SHBG)). The extent to which this relationship is true in healthy female populations and whether RFD influences androgen responses to resistance exercise has not been fully described. This study examined the effects of RFD on total testosterone (TT), FT, and SHBG responses to an acute resistance exercise test (ARET) among 47 women (22 ± 3 yr.; 165 ± 6 cm; 62 ± 8 kg; 25 ± 5%BF; 23 ± 3 BMI). RFD was characterized by 2 separate indices: waist-to-hip ratio (WHR) and ratio of upper arm fat to mid-thigh fat (ALFATR) assessed via magnetic resonance imaging. The ARET consisted of 6 sets of 10RM squats separated by 2 min rest periods. Blood was obtained via venipuncture pre and post the ARET. TT, FT, and SHBG concentrations were determined by radioimmunoassay. Subjects were divided into tertiles from the indices of RFD and statistical analyses were performed via an ANOVA with repeated measures (RFD and exercise as main effects). Significant (p≤.05) group effects existed for ALFATR, but not WHR. This indicated that women with upper body fat patterning possessed higher concentrations of FT (7.33 vs. 10.81 pmol/L for ALFATR tertiles 1 and 3 respectively). Main effects were observed for exercise demonstrating that the ARET served as a potent stimulus for acute increases in TT (1.24 vs. 1.55 nmol/L;≈25% rise), FT (≈24% rise) and SHBG (≈4%). We conclude that for young healthy women: 1) resistance exercise can induce transient increases in androgen levels and 2) the use of ALFATR may be more discriminant than the WHR for assessing metabolic profiles associated with RFD.