What to watch with SHBG and Sport?

SHBG (sex hormone-binding globulin) is a protein that binds sex steroids like testosterone and estradiol in the blood, regulating their bioavailability. In sports, SHBG levels can be influenced by various factors: intense endurance exercise tends to lower SHBG acutely, while strength training and caloric restriction may increase it. Low SHBG is often linked to insulin resistance, metabolic syndrome, and higher free testosterone – which might temporarily enhance performance but could indicate long-term hormonal imbalance. High SHBG reduces free, biologically active testosterone, potentially impairing recovery and muscle building. Important: SHBG levels show strong individual and circadian variation. A DNA test for SHBG gene variants (e.g., in the SHBG gene) only indicates genetic predisposition, not current levels. For athletes, blood measurement of SHBG, total testosterone, and free testosterone is more informative. Evidence for direct action recommendations from SHBG genetics is weak. Consult an endocrinologist if abnormalities arise.