Hormonal balance and nutritional intake in elite tactical athletes

Chronic exposure to multifactorial stress, such as that endured by elite military operators, may lead to overtraining syndrome and negatively impact hormonal regulation. In acute settings (<6 mos), military training has been shown to lead to hormonal dysfunction; however, less is known about the consequences of long-term military training. Thus, the purpose of this study was to determine the chronic effects of military operations and training on the hormone profile of elite military operators. A cross-sectional, random sample of active duty elite US military operators (n = 65, age = 29.8 ± 1.0 yrs, height = 178.4 ± 0.7 cm, weight = 85.1 ± 2.0 kg) concomitantly engaged in rigorous physical training were recruited to participate in the study. Following an overnight fast, waking plasma concentrations of luteinizing hormone, total testosterone (TT), free testosterone, sex-hormone binding globulin, cortisol, thyroid stimulating hormone, triiodothyronine, and thyroxine were obtained. Data were analyzed for correlations and compared against normative reference values. There was a significant positive correlation between TT and cortisol (R² = 0.07; P = 0.038). In addition, 43% of the participants (n = 28) had TT below age-based normative reference ranges. These results indicate that long-term military operations and training may place a large burden on the operators and depress or alter the hypothalamic pituitary, adrenal, gonadal, and thyroid axes.