Hormonal Changes in High-Level Aerobic Male Athletes during a Sports Season

Abstract

The aim of this study was to determine the possible changes in plasma of several hormones such as Luteinizing Hormone, Testosterone, Cortisol and Insulin in endurance runners during the sports season. Twenty-one high-level male endurance runners (22 ± 3.2 years, 1.77 ± 0.05 m) participated in the study. Basal plasma hormones were measured at four moments during the season (initial, 3, 6 and 9 months), and were analyzed using ELISA (enzyme-linked immunosorbent assay). Testosterone and Luteinizing Hormone (LH) suffered very significant decreases (p < 0.01) at 3 months compared with the beginning and an increase (p < 0.05) at 6 and 9 months compared with 3 months. Insulin level was significantly lower (p < 0.05) at 3, 6 and 9 months compared with the initial test. Insulin and cortisol were associated inversely (r = 0.363; β = −0.577; p = 0.017) and positively (r = 0.202; β = 0.310; p = 0.043), respectively, with the amount of km per week performed by the runners. There was a significant association between km covered at a higher intensity than the anaerobic threshold and I (r = 0.580; β = −0.442; p = 0.000). Our findings indicate that testosterone, LH and insulin were more sensitive to changes in training volume and intensity than cortisol in high-level endurance runners. Basal testosterone and LH concentrations decrease in athletes who perform a high volume of aerobic km in situations of low energy availability.

Correlations between Basal Trace Minerals and Hormones in Middle and Long-Distance High-Level Male Runners

“…Research has reported on the relationship between energy intake and the synthesis of anabolic hormones [ 20 , 21 ]. High-level endurance runners in training periods with an intake below 45 calories per day per kg of fat-free mass (FFM) had decreases in LH and T hormones [ 22 ]. As mentioned above, significant interactions have been observed between TM concentrations and the endocrine system.…”

Low Energy Availability and Relative Energy Deficiency in Sport: What Coaches Should Know

“…Thyroid deficiency generally leads to an energy preservation state, in which energy normally reserved for growth and reproduction is reduced and diverted to more vital functions 117 . As such, athletes in LEA states have reduced thyroid hormone levels 25,68,77,115,118 . These deficiencies result in decreased growth and reproductive function, which is evident when considering the amenorrheic athlete 119 .…”

“…Insulin is also an anabolic hormone: it activates glucose uptake, glycogen synthesis, protein synthesis, and inhibits protein degradation 25,116,120,121 . Circulating glucose is the primary source of energy in the body; blood glucose is tightly regulated by insulin and its counteracting hormone, glucagon.…”

“…Growth hormone acts via IGF-1, which also acts to regulate growth hormone secretion 77 . Athletes experiencing LEA exhibit elevated growth hormone levels but reduced circulating IGF-1, suggesting that resistance within this pathway has developed during LEA 25,68,114,115 . The overall effect of these changes is decreased muscle synthesis, bone anabolism, growth, and repair.…”

“…Cortisol is primarily a catabolic hormone 25,116 that acts to promote energy supply, in part through muscle protein breakdown and lipolysis (breakdown of fats). Those experiencing LEA exhibit elevated levels of cortisol, which promotes a catabolic state that can restrict muscle glycogen stores, promote proteolysis of muscle tissue and promote resorption of bone tissues 25,77,116 , thus increasing risk of injury and illness.…”