madman
Super Moderator
Endogenous transient doping: physical exercise acutely increases testosterone levels—results from a meta‑analysis
Abstract
Purpose: Although endogenous testosterone levels are demonstrated to be affected by both acute exercise and resistance training, the dynamic regulation of androgen production after physical activity is still a matter of debate. This meta-analysis was designed to assess whether physical exercise acutely affects testosterone levels in men.
Methods: The literature search was conducted to identify longitudinal trials evaluating the acute change of both total testosterone (TT) and free testosterone (fT) after physical activity in adult men. Sensitivity analyses were performed considering the sample collected (blood or saliva), the intensity of the physical exercise and the interval between the end of the exercise and the sample collection.
Results: Forty-eight studies were included in the analysis, accounting for 126 trials. A total of 569 patients were enrolled (mean age 29.7±13.1 years). The physical activity increased acutely TT (standardized mean difference 0.74, 95%CI: 0.56, 0.91 nmol/L), considering both serum and saliva samples (p<0.001). Testosterone increased after moderate (p<0.001) and high-intensity (p<0.001) exercises, but not after mild physical activity (p=0.19). Moreover, the testosterone increase was evident when measured immediately at the end of the exercise and within 30 min (p<0.001), but not after 30 min (p=0.930). Similar significant results were obtained considering fT, while SHBG did not change after physical activity (p=0.090).
Conclusion: The comprehensive evaluation of the acute physical activity effect on testosterone levels identified a clear increase after exercise, irrespective of the sample collected. The main determinant of this fluctuation was the exercise intensity, with a mechanism that seems to be mostly SHBG independent. In particular, moderate/intense physical activity resulted able to increase endogenous androgenic production, albeit acutely and transitory.
In conclusion, acute exercise increases free and total testosterone levels. This increase is detectable in both blood and salivary samples within 30 min after the end of physical exercise. The main determinant of this increase is the intensity of exercise, with a mechanism independent of SHBG. Specifically, moderate and intense physical exercise induces a transitory increase in testosterone levels. Further proper designed studies are needed to clarify the exact mechanism by which HPG axis is modulated by physical activity and the possible biological significance of such variations.
Abstract
Purpose: Although endogenous testosterone levels are demonstrated to be affected by both acute exercise and resistance training, the dynamic regulation of androgen production after physical activity is still a matter of debate. This meta-analysis was designed to assess whether physical exercise acutely affects testosterone levels in men.
Methods: The literature search was conducted to identify longitudinal trials evaluating the acute change of both total testosterone (TT) and free testosterone (fT) after physical activity in adult men. Sensitivity analyses were performed considering the sample collected (blood or saliva), the intensity of the physical exercise and the interval between the end of the exercise and the sample collection.
Results: Forty-eight studies were included in the analysis, accounting for 126 trials. A total of 569 patients were enrolled (mean age 29.7±13.1 years). The physical activity increased acutely TT (standardized mean difference 0.74, 95%CI: 0.56, 0.91 nmol/L), considering both serum and saliva samples (p<0.001). Testosterone increased after moderate (p<0.001) and high-intensity (p<0.001) exercises, but not after mild physical activity (p=0.19). Moreover, the testosterone increase was evident when measured immediately at the end of the exercise and within 30 min (p<0.001), but not after 30 min (p=0.930). Similar significant results were obtained considering fT, while SHBG did not change after physical activity (p=0.090).
Conclusion: The comprehensive evaluation of the acute physical activity effect on testosterone levels identified a clear increase after exercise, irrespective of the sample collected. The main determinant of this fluctuation was the exercise intensity, with a mechanism that seems to be mostly SHBG independent. In particular, moderate/intense physical activity resulted able to increase endogenous androgenic production, albeit acutely and transitory.
In conclusion, acute exercise increases free and total testosterone levels. This increase is detectable in both blood and salivary samples within 30 min after the end of physical exercise. The main determinant of this increase is the intensity of exercise, with a mechanism independent of SHBG. Specifically, moderate and intense physical exercise induces a transitory increase in testosterone levels. Further proper designed studies are needed to clarify the exact mechanism by which HPG axis is modulated by physical activity and the possible biological significance of such variations.
