Training to muscle failure on a regular basis is associated with higher levels of the stress hormone cortisol and slower recovery of the nervous system, which may limit the amount of muscle gained...
Mechanism
Synthesis from 1 study
Training until you can't do another rep makes your muscles and nerves extremely tired, which tells your body to release more stress hormone cortisol (10.1080/02640414.2024.2321021). This extra cortisol makes it harder for your brain to fully activate your muscles in future workouts, slowing...
Most probable mechanism
When someone trains to muscular failure, their muscles and nerves get extremely tired, which signals the brain to release more stress hormones like cortisol (10.1080/02640414.2024.2321021). This extra cortisol makes it harder for the brain to send strong signals to the muscles during future workouts, slowing down recovery and potentially limiting how much muscle can grow over time.
Training to muscular failure increases acute neuromuscular fatigue through greater motor unit recruitment and metabolic stress, as evidenced by higher velocity and repetition loss compared to training with repetitions-in-reserve (10.1080/02640414.2024.2321021).
Elevated neuromuscular fatigue acts as a physiological stressor that activates the hypothalamic-pituitary-adrenal (HPA) axis, leading to increased systemic cortisol secretion, a well-established response to intense, fatiguing exercise (10.1080/02640414.2024.2321021).
Elevated cortisol levels suppress central nervous system (CNS) recovery by reducing motor cortex excitability and impairing motor unit recruitment efficiency, which is inferred from the persistent neuromuscular fatigue observed despite similar hypertrophic outcomes (10.1080/02640414.2024.2321021).
Chronic suppression of CNS recovery reduces the ability to generate maximal force output across training sessions, limiting the cumulative mechanical tension stimulus required for optimal long-term muscle growth, despite equivalent acute hypertrophy from similar training volumes (10.1080/02640414.2024.2321021).
Evidence from Studies
Supporting (1)
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