🟠 Moderate Evidence
When skeletal muscle contracts during exercise, it releases signaling molecules called myokines that travel through the bloodstream to the brain, where they regulate learning, memory, blood flow, and inflammatory balance, according to research in the field of exercise physiology. These molecular messengers function as a form of endocrine communication, making muscle tissue act like an organ that directly influences neurological function. The discovery has reshaped scientific understanding of how physical activity supports cognitive health across the lifespan.
Key takeaways
- Skeletal muscle releases at least five key myokines—BDNF, IGF-1, irisin, IL-6, and VEGF—that signal to the brain
- Different exercise types produce distinct myokine profiles: aerobic exercise favours neuroplasticity signalling, resistance training emphasises repair and growth
- Regular physical activity maintains myokine communication with age; declines in myokine release correlate with reduced cognitive resilience
Myokine Signalling Profiles by Exercise Type
Relative strength of myokine signals produced during different training modalities
Source: Exercise physiology literature | Georgian Medical Journal News
Five key myokines and their brain effects
BDNF (brain-derived neurotrophic factor) increases significantly with aerobic exercise and supports synaptic plasticity, memory formation, and neurogenesis. This myokine is widely studied in the context of cognitive ageing and neurodegenerative disease prevention. IGF-1 (insulin-like growth factor-1), elevated following resistance training, promotes neuronal survival, repair, and long-term brain plasticity. Both molecules have been documented in published studies examining exercise-induced neuroprotection.
Irisin is produced when the FNDC5 protein is cleaved during muscle contraction and influences brain metabolism and inflammatory pathways. IL-6 (interleukin-6), released in large amounts during sustained exercise, regulates energy availability and exerts anti-inflammatory effects in the post-exercise period. VEGF (vascular endothelial growth factor), stimulated by endurance training, supports angiogenesis—the formation of new blood vessels—improving cerebral blood flow and oxygen delivery to neural tissue. Together, these molecules form a coordinated signalling network that adapts to the type and intensity of physical activity performed.
Skeletal muscle behaves as an endocrine organ, with myokine release directly linked to maintenance of cognitive resilience and mitochondrial function across the lifespan. Declines in myokine signalling correlate with reduced neurological reserve in ageing populations.
— Exercise Physiology Research Community
How exercise type shapes myokine profiles
The myokine response is not uniform across all forms of physical activity. Aerobic exercise produces stronger signals for neuroplasticity and vascular adaptation, supporting learning and memory functions through BDNF and VEGF elevation. Resistance training generates a distinct profile emphasizing repair, growth, and metabolic regulation, primarily through IGF-1 and IL-6 signalling. Interval or combined training modalities produce a blended signalling pattern with broad cognitive and metabolic benefits.
This exercise-specific variation explains why guidelines increasingly recommend mixed training regimens rather than single modalities. A person who performs only steady-state running will activate a different molecular signature than someone combining aerobic and resistance work. For clinical and public health purposes, this finding underscores the importance of exercise diversity in optimizing both physical and cognitive outcomes. The recommendation from international health organizations for 150 minutes of moderate aerobic activity plus resistance training aligns with the need to activate multiple myokine pathways.
Myokine decline with ageing and preservation through activity
Across published studies, regular physical activity maintains the muscle–brain communication system as people age. Myokine release capacity declines with sedentary behaviour and advancing age, a phenomenon linked to reduced cognitive resilience, slower recovery from neurological injury, and impaired mitochondrial function. Conversely, consistent training helps preserve myokine signalling capacity, vascular health, and anti-inflammatory signalling in the brain. This finding has important implications for dementia prevention and healthy cognitive ageing strategies.
The evidence suggests that the decline in myokine communication is not inevitable but modifiable through sustained physical activity. Even moderate-intensity exercise performed regularly can maintain circulating myokine levels and preserve their neuroprotective effects. This positions exercise as a fundamental component of neurological health maintenance across the lifespan—not simply as a cardiovascular or metabolic intervention. The biochemical link between muscle contraction and brain function represents a critical pathway in the prevention of age-related cognitive decline.
Research in this field continues to identify additional myokines and clarify the mechanisms by which their signalling supports specific cognitive and neuroprotective functions. Understanding this muscle–brain axis opens new avenues for both pharmacological research aimed at mimicking myokine effects and reinforces the evidence base for physical activity as a primary preventive health intervention. For clinicians, this knowledge supports prescribing exercise with confidence as a clinical intervention grounded in molecular and systems physiology.
What this means
Frequently asked questions
How quickly do myokines reach the brain after exercise?
Myokines enter systemic circulation within minutes of muscle contraction and can reach the brain via the bloodstream rapidly thereafter. Peak concentrations of signalling molecules like BDNF and IL-6 are typically observed within 30 minutes to 1 hour after exercise cessation, though some myokines maintain elevated levels for several hours post-exercise.
Do all types of exercise produce the same myokine response?
No. Aerobic exercise primarily elevates BDNF and VEGF, supporting neuroplasticity and vascular adaptation. Resistance training emphasises IGF-1 and IL-6 for muscle repair and growth signalling. Combined or interval training activates multiple myokine pathways simultaneously, which is why mixed exercise regimens are recommended for comprehensive cognitive and metabolic benefits.
Can myokine decline be reversed in older adults?
Yes. Research indicates that consistent physical activity in older adults can preserve or partially restore myokine signalling capacity. Even moderate-intensity exercise performed regularly maintains circulating myokine levels and their neuroprotective effects, suggesting that age-related declines in myokine communication are modifiable through sustained activity rather than inevitable.
The emerging science of myokines demonstrates that physical movement is not merely mechanical effort but a form of biochemical communication that supports the nervous system with every muscle contraction. As research continues to map additional myokine pathways and clarify their cognitive and neuroprotective mechanisms, exercise becomes increasingly recognized as a foundational intervention for neurological health. For individuals seeking evidence-based approaches to cognitive health, this science provides both a molecular explanation for why physical activity matters and a practical guide for exercise prescription across all ages and fitness levels.
Source: Exercise physiology and myokine signalling research (PMID: 38008091)
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