Relationship between salivary and serum testosterone levels in response to different exercise intensities.

Abstract

The anabolic hormone testosterone (T) continues to be researched extensively in exercise studies, with blood serum or plasma samples collected routinely. This method is considered both valid and reliable; however, the collection process can be invasive and difficult during exercise. For this reason, non-invasive sampling, such as saliva collections, is increasing in popularity. To investigate the association between salivary and serum T before and after various intensities of exercise to assess the validity of saliva collection for T measurement. 12 endurance-trained males (Mean ± SD; VOVO2max 58.2 ± 6.4 ml/kg/min, 22 ± 4.6 years, BMI 21.6 ± 1.9) completed three 30-minute exercise (cycling) sessions at 40% (Low), 60% (Moderate), and 80% (High) of VO2max as well as a 30-minute resting Control session on four separate days. Salivary (s) and serum (S) samples were assessed for T prior to (Pre), immediately post (Post), and 30 minutes post (30 Min Post) each session. Low exercise caused a significant (p<0.05) increase in ST, but not sT, while Moderate and High exercise caused an increase (p<0.01) in both ST and sT. A strong positive correlation (Spearman [rs]) existed between sT and ST in the Moderate (rs = 0.912 [p<0.001; n=36; 12 subjects x 3 measurement times-samples]), and High (rs = 0.898 [p<0.001]) sessions, but not as strong for the Low (rs = 0.517 [p=0.001]) session. These results suggest that sT and ST levels are strongly associated to exercise. However, the exercise-related sT and ST responses-changes were more closely aligned at Moderate and High intensities, suggesting a greater validity between the saliva and serum responses to higher intensity exercise.