Reproductive hormones and interleukin-6 in serious leisure male athletes.

Lifestyles associated with different types and intensities of exercise result in improved health including positive changes in chronic low-grade inflammatory biomarkers. Alternatively, some forms of exercise adversely affect reproductive health of men, including changes in circulating reproductive hormones. To explore the associations between exercise intensity and circulating levels of reproductive hormones, and inflammatory analytes in serious leisure athletes (triathletes and cyclists) and recreational athletes. Male athletes 18-60 years old, 16 triathletes, 46 cyclists and 45 recreational athletes, were recruited to provide plasma for the measurement of total testosterone, estradiol, follicular stimulating hormone, luteinizing hormone (LH), sex hormone-binding globulin (SHBG), cortisol, interleukin-6 (IL-6), and interleukin-1β (IL-1β) levels, and calculation of free androgen index (FAI) and the estradiol:SHBG ratio (ESR). Plasma estradiol concentrations were more than two times higher in cyclists than in triathletes and recreational athletes (p < 0.01). Testosterone levels were also higher in cyclists than recreational athletes (p < 0.01), but not significantly different from triathletes. SHBG levels were higher in triathletes and cyclists than in recreational athletes (p < 0.01). LH levels were lower in cyclists than in recreational athletes (p < 0.05). IL-6 and IL-1β levels were each two times lower in triathletes than in cyclists (p < 0.05) and IL-6 levels were lower in cyclists than in recreational athletes (p < 0.01). IL-1β levels were two times lower in triathletes than in cyclists (p < 0.05). Circulating estradiol and testosterone levels were elevated in serious leisure male cyclists. This effect is discussed in light in the absence of a substantial concomitant change in gonadotropin levels and other variables.