For decades, physical exercise has been recommended primarily for its cardiovascular and musculoskeletal benefits.
More recently, however, neuroscience has revealed a compelling connection between skeletal muscle and brain health, a relationship now commonly referred to as the muscle–brain axis.
Central to this link is a protein called brain-derived neurotrophic factor (BDNF), which plays a crucial role in mood regulation, learning and memory.
While aerobic exercise has long been associated with cognitive benefits, growing evidence suggests that strength (resistance) training also exerts powerful effects on the brain.
This article explores how strength training influences BDNF and how this, in turn, supports mental well-being and cognitive performance.
Understanding BDNF: The Brain’s Growth Factor
BDNF is a neurotrophin, a type of protein that supports the survival, growth and differentiation of neurons. It is particularly active in brain regions involved in learning, memory and emotional regulation, such as the hippocampus and prefrontal cortex.
Adequate levels of BDNF are essential for:
- Neuroplasticity, the brain’s ability to adapt and reorganise
- Memory formation and recall
- Emotional stability and stress resilience
Conversely, reduced BDNF levels have been associated with conditions such as depression, anxiety disorders, cognitive decline and neurodegenerative diseases.
Skeletal Muscle as an Endocrine Organ
Skeletal muscle is no longer viewed solely as a system for movement and strength. It is now recognised as an endocrine organ, capable of releasing signalling molecules known as myokines during contraction.
During strength training, contracting muscles release myokines that communicate with distant organs, including the brain. Some of these myokines stimulate BDNF production either directly within the brain or indirectly by influencing metabolic and inflammatory pathways.
This biochemical cross-talk is a key component of the muscle–brain axis.
How Strength Training Influences BDNF
1. Increased BDNF Expression
Research indicates that resistance training can increase circulating and brain BDNF levels, particularly when exercises are performed at moderate to high intensity. This rise in BDNF supports synaptic plasticity, enhancing the brain’s ability to form and strengthen neural connections.
2. Improved Mood and Reduced Depressive Symptoms
Strength training has been shown to reduce symptoms of depression and anxiety, even in the absence of significant muscle hypertrophy.
BDNF is thought to mediate part of this effect by supporting neuronal health and regulating neurotransmitter systems involved in mood, such as serotonin and dopamine.
Importantly, these benefits are observed across age groups, including older adults.
3. Enhanced Memory and Cognitive Function
BDNF plays a critical role in hippocampal function, the brain’s memory centre. By increasing BDNF availability, strength training may improve:
- Working memory
- Executive function
- Learning speed and retention
Emerging evidence suggests resistance training may be particularly beneficial for preserving cognitive function during ageing.
Strength Training vs Aerobic Exercise
Aerobic exercise is often highlighted as the most effective way to boost BDNF.
However, strength training offers complementary benefits and may be especially valuable for individuals who cannot tolerate high-impact or endurance-based activities.
Notably:
- Strength training improves insulin sensitivity and reduces chronic inflammation, both of which indirectly support brain health.
- Combined aerobic and resistance programmes appear to produce the greatest overall cognitive benefits.
Rather than choosing one over the other, a balanced exercise routine is likely to be optimal for brain function.
Practical Implications for Brain Health
From a clinical and public health perspective, these findings reinforce the importance of including strength training in regular physical activity guidelines. For cognitive and mental health benefits, current evidence supports:
- 2-3 strength training sessions per week
- Exercises targeting major muscle groups
- Progressive resistance, tailored to individual ability and health status.
As with any exercise programme, individuals with medical conditions should seek professional guidance before beginning.
Summary
The muscle-brain axis highlights an important shift in how we understand the relationship between physical strength and mental function.
Through the modulation of BDNF and other signalling molecules, strength training supports mood regulation, memory and overall cognitive resilience.
Far from being beneficial only for muscles and bones, resistance exercise emerges as a powerful, accessible tool for long-term brain health, reinforcing the idea that a stronger body can help build a strong mind.
