The exercise-induced growth hormone response in athletes

Area of Science:

• Exercise Physiology
• Endocrinology
• Sports Science

Background:

• Human growth hormone (hGH) is crucial for growth, metabolism, and body composition.
• hGH secretion follows a circadian rhythm and is stimulated by factors like sleep and exercise.
• The exercise-induced growth hormone response (EIGR) mechanisms are complex, involving neural input, catecholamines, lactate, and nitric oxide.

Purpose of the Study:

• To review current knowledge on the mechanisms of EIGR.
• To examine the physiological consequences of different training types on EIGR.
• To explore the potential benefits of optimizing EIGR in aging populations and athletes.

Main Methods:

• Review of existing scientific literature on hGH secretion and exercise.
• Analysis of studies investigating resistance and endurance exercise effects on EIGR.
• Examination of proposed mechanisms for EIGR, including lactate and nitric oxide pathways.

Main Results:

• Resistance training significantly increases EIGR, influenced by load and frequency.
• Endurance exercise EIGR depends on intensity, duration, and frequency, with intensity above lactate threshold being key.
• Chronic endurance training may lead to decreased resting hGH and a blunted EIGR, possibly due to increased tissue sensitivity.

Conclusions:

• High-intensity exercise, particularly above the lactate threshold, is most effective for stimulating hGH secretion.
• Optimizing exercise programs to enhance EIGR could offer health benefits, especially for aging individuals.
• Further research is needed to clarify the long-term effects of chronic training on EIGR and its implications.