Related Experiment Video
Updated: May 25, 2026
04:28
Evaluation of Blood Lactate and Plasma Insulin During High-intensity Exercise by Antecubital Vein Catheterization
Published on: May 18, 2018
Leptin and endocrine parameters in marathon runners.
1Charité, Department of Endocrinolgy, Diabetes and Nutrition, Berlin, Germany. thomas.bobbert@charite.de
International Journal of Sports Medicine
|January 21, 2012
Summary
Endurance exercise impacts hormones. Well-trained marathon runners show anabolic hormonal responses, while less trained runners exhibit increased stress hormones, linked to leptin levels.
Area of Science:
- Endocrinology
- Sports Medicine
- Exercise Physiology
Background:
- Endurance training can cause hormonal imbalances, including hypothalamic-pituitary dysfunction.
- Leptin, a key metabolic hormone, plays a role in regulating energy balance and reproductive function.
- Understanding the interplay between exercise, leptin, and hormonal responses is crucial for athletes' health.
Purpose of the Study:
- To investigate the relationship between physical exercise, leptin levels, and hormonal alterations in marathon runners.
- To identify specific hormonal changes associated with different training statuses and marathon performance.
- To explore the role of leptin in exercise-induced neuroendocrine adaptations.
Main Methods:
- Blood samples were collected from 36 male participants of the Berlin Marathon two days prior to the event.
- Hormones of the hypothalamic-pituitary axis and leptin levels were measured.
- Hormonal data were correlated with participants' training status and achieved marathon times, adjusted for age and BMI.
Main Results:
- Leptin levels showed a significant positive correlation with marathon time (r=0.607, p<0.001), being lowest in the best-trained runners.
- The slowest running group exhibited elevated cortisol, free thyroxine (fT4), and cortisol/dehydroepiandrosterone sulfate (DHEAS) ratio, with decreased insulin-like growth factor 1 (IGF-1).
- Better-trained runners displayed a reduced testosterone/dihydrotestosterone (DHT) ratio and an increased testosterone/cortisol ratio.
Conclusions:
- A linear relationship exists between physical fitness and leptin variations within the physiological range.
- Well-trained marathon runners exhibit enhanced anabolic hormonal profiles, whereas less trained runners show signs of increased stress.
- Neuroendocrine adaptations to stress in athletes are associated with higher leptin values, suggesting a limited pathophysiological role for decreased leptin in overtrained individuals.
