What triggers the release of insulin-like growth factor-1 (IGF-1)?

The release of insulin-like growth factor-1 (IGF-1) is primarily stimulated by appropriately-devised hypertrophy training. This form of training typically involves resistance exercises that promote muscle growth through mechanical tension and metabolic stress. When muscles experience tension from lifting weights, growth hormones are released, and in response to those signals, the liver and other tissues produce IGF-1.

IGF-1 plays a crucial role in muscle repair and growth by promoting the proliferation and differentiation of satellite cells, which contribute to muscle hypertrophy. Thus, a structured training program that focuses on building muscle size through resistance training will effectively stimulate IGF-1 release, contributing to overall muscle development and recovery.

In contrast, intense endurance training may not have the same pronounced effect on IGF-1 levels as hypertrophy-focused workouts do. Similarly, high-stress situations can lead to the release of cortisol, a hormone that can actually inhibit muscle growth and potentially reduce IGF-1 levels. Lastly, low carbohydrate intake can negatively impact energy levels and performance in resistance training, which may indirectly reduce the effective stimulus for IGF-1 release, further emphasizing the importance of nutrient intake in conjunction with the type of training.