Prediction of serum testosterone before and after an exercise program using physiological and personality variables

Area of Science:

• Endocrinology and Exercise Physiology
• Psychology and Human Performance

Background:

• Serum testosterone levels are linked to various physiological and psychological factors in males.
• Physical fitness programs may influence hormonal profiles and personality traits.

Purpose of the Study:

• To investigate the relationship between serum testosterone and physiological/personality variables before and after a fitness program.
• To identify predictors of serum testosterone levels in adult males undergoing physical training.

Main Methods:

• 58 males (21-61 years) participated in a 4-month fitness program (jogging, calisthenics, recreation).
• Serum testosterone measured via radioimmunoassay; physical fitness assessed using regression equations.
• Multiple correlation and stepwise linear regression analyzed relationships between testosterone and 19 variables (demographics, anthropometrics, personality scales).

Main Results:

• Significant improvements in physical fitness (p < 0.01) were observed post-program.
• Pre-test: Significant multiple correlations (R=0.77) linked testosterone to neuroticism, emotional stability, aggression, and intelligence.
• Post-test: Correlations remained significant (R=0.67), with 'percent lean body weight' emerging as a predictor, while aggression and intelligence factors diminished.

Conclusions:

• Physical fitness programs can alter the predictive relationships between serum testosterone and personality traits.
• Changes in body composition (percent lean) may reflect testosterone's influence on physical adaptations to exercise.
• The diminished role of aggression post-exercise may relate to hormonal changes associated with habitual physical activity.