Ageing affects all organs, but the brain ages differently than the rest of the body. Researchers have found that as we grow older, many genes in the brain become less active. This decline contributes to cognitive decline and neurodegenerative diseases such as Alzheimer's and Parkinson’s.
However, recent studies suggest that certain lifestyle choices, such as physical activity, can slow down or even reverse some aspects of brain ageing.
Brain Ageing: A Unique Process
Ageing affects the brain’s gene activity in a distinct way. Unlike other tissues, the brain experiences a significant downregulation of genes that are essential for neuron function. Researchers analysed RNA sequencing data from 32 different human tissues and found that while ageing affects all parts of the body, the brain undergoes more pronounced genetic changes.
Among these changes, genes involved in synaptic function, mitochondrial activity, and protein recycling decline significantly. These functions are critical for memory, learning, and overall cognitive performance. The loss of these functions contributes to neurodegenerative diseases and cognitive decline.
Ageing and Neurodegeneration: The Connection
Neurodegenerative diseases, such as Alzheimer’s and Parkinson’s, become more common as people age. This is because many important genes in the brain naturally decline over time. However, in these diseases, the decline becomes much more severe and happens faster than in normal ageing. This suggests that ageing plays a major role in triggering neurodegeneration.
In Alzheimer’s disease, the hippocampus, a part of the brain essential for memory and learning, is particularly affected. During normal ageing, gene activity in the hippocampus decreases, but in Alzheimer’s, this decline is even more extreme. This rapid loss of function leads to memory problems, which is why forgetfulness is often one of the first symptoms of Alzheimer’s.
Parkinson’s disease mainly affects movement and coordination. It is linked to problems in the substantia nigra, a part of the brain that produces dopamine, a chemical needed for smooth and controlled movements. As people age, this area already experiences some loss of function, but Parkinson’s disease greatly accelerates the damage. This leads to tremors, stiffness, and difficulty moving, which are key symptoms of Parkinson’s.
How Physical Activity Slows Brain Ageing
One of the most exciting discoveries in brain ageing research is that exercise can slow down or even reverse some of the genetic declines that come with ageing. Scientists have found that people who stay physically active—especially those who engage in high levels of exercise—experience a reactivation of key brain-related genes, particularly in the hippocampus, the region responsible for memory and learning.
As we age, certain genes in the brain become less active, which can lead to memory loss and increased risk of diseases like Alzheimer’s and Parkinson’s. However, research shows that physical activity can restore the activity of these genes, particularly those that control:
- Synaptic function – Synapses are connections between neurons that allow brain cells to communicate. Exercise helps maintain these connections, which are essential for memory, learning, and cognitive function.
- Mitochondrial energy production – Mitochondria are the "powerhouses" of cells, providing the energy needed for brain function. Exercise boosts mitochondrial activity, ensuring neurons get the energy they need to function properly.
Another major finding is that physical activity protects neurons from dying. The hippocampus, which naturally shrinks with age, maintains more neurons in people who exercise regularly compared to those who live sedentary lifestyles. This means that staying active not only preserves brain structure but also supports brain function well into old age.
Why This Matters
These findings suggest that exercise is one of the most effective ways to keep the brain healthy as we age. By maintaining gene activity, supporting energy production, and preventing neuron loss, physical activity reduces the risk of cognitive decline and neurodegenerative diseases. Simply put, staying active helps protect memory, boost brain power, and promote long-term brain health.
Other Anti-Ageing Strategies
Apart from physical activity, other interventions like calorie restriction and certain medications have been studied for their potential anti-ageing effects.
Scientists have explored different strategies to slow down ageing and preserve brain function. Two of the most studied approaches are calorie restriction and metformin treatment. Both methods have shown some benefits in ageing, but their effectiveness, especially for the brain, varies.
Calorie Restriction and Brain Ageing
Calorie restriction (CR) means reducing daily calorie intake while still getting enough nutrients. Research has shown that eating fewer calories can influence gene expression, helping to slow the ageing process at the cellular level. However, its effectiveness depends on maintaining consistent weight loss over time.
For example, people who successfully lost and maintained weight through calorie restriction showed signs of reversing some ageing-related changes. On the other hand, individuals who started restricting calories but later regained weight did not experience the same benefits. This suggests that for calorie restriction to be effective, it must be consistent and long-term.
Metformin as an Anti-Ageing Drug
Metformin is a widely used diabetes medication that has gained attention for its potential anti-ageing effects. Scientists have studied metformin because it mimics some of the effects of calorie restriction, particularly in reducing inflammation and improving metabolism. However, in this study, metformin did not significantly reverse ageing-related gene changes in the brain.
This means that while metformin might help in other aspects of ageing—such as improving insulin sensitivity or reducing inflammation—it may not be as effective in protecting the brain from ageing-related decline as calorie restriction or exercise.
Ageing is inevitable, but cognitive decline doesn’t have to be. Research suggests that staying physically active is one of the most effective ways to preserve brain health and delay neurodegeneration. By understanding the genetic mechanisms of brain ageing, scientists are uncovering new ways to promote healthy ageing and improve quality of life.
The study is published in the journal Frontiers in Aging Neuroscience. It was led by researchers from Sun Yat-sen University in China.
