When muscles are strongly activated during physical exercise, the body produces more insulin-like growth factor 1 (IGF-1), a protein involved in tissue growth and repair.
Evidence from Studies
Supporting (4)
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Acute effects of physical exercise on the serum insulin-like growth factor system in women with fibromyalgia
When people exercise, especially by pedaling a bike hard or even moderately, their bodies release more IGF-1 — a protein that helps muscles grow and repair. This study showed that even a short bike ride can boost IGF-1 levels, supporting the idea that working your muscles makes your body produce more of this helpful protein.
Humans with obesity exhibit impaired circulating total, but not free, IGF‐1 response to acute endurance exercise
When people exercise hard, their bodies make more IGF-1, a hormone that helps muscles grow and repair—even if some of it gets tied up and doesn’t circulate freely. This study showed that happens in healthy people.
Effect of different muscle contraction mode on the expression of Myostatin, IGF-1, and PGC-1 alpha family members in human Vastus Lateralis muscle
When you work your muscles hard during exercise, your body responds by turning on genes that make more IGF-1, a protein that helps muscles grow and repair. This study showed that lifting weights (both pushing and lowering) causes this gene to activate.
When you work out hard and damage your muscles, your body responds by activating a growth system linked to IGF-1 — like turning on a repair signal. This study found proof that exercise triggers this system in human muscle.
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