Anna Mallach explores physical exercise, the practice of mindfulness and the positive effects these could have on the brain
In Western society, an increasingly sedentary lifestyle is being led and, paradoxically, with the prevalence of desk work increasing, so is a fitness culture. Apart from losing weight, exercise can also have other positive effects on well-being, and the ‘runner’s high’ is a well-known phenomenon. But why does one feel better during and after exercising and how does muscle activity in the legs lead to positive changes in the brain?
First of all, not exercising has negative effects on the brain in its own right. Physical inactivity, and associated obesity, can lead to cardiovascular problems and Type 2 diabetes, and these diseases have a negative impact on the brain. The neurons of the brain are highly dependent on a high and constant blood supply, and when this is reduced, as it is in cardiovascular diseases and diabetes, neurons degenerate and die.
Exercise, however, has more effects on the brain than simply mitigating the negative implications of not exercising. This has been studied extensively in ageing adults. The age-related decline of cognitive function leaves the older population more susceptible to the development of neurodegenerative diseases, such as dementia. However, this provides the ideal setting to investigate whether exercise is able to reverse these age-related cognitive changes.
A range of studies have highlighted a positive correlation between exercise and cognitive function, particularly executive processes such as scheduling, planning, multi-tasking and memory. In addition, the communication pattern of the entire brain appears to change to enable quicker allocation of resources to areas required for a particular process.
On a cellular level, researchers have mainly investigated the hippocampus, the region of the brain involved in memory formation and learning. The hippocampus is one of the few regions where neurons continue to be born throughout life, making this process essential for memory formation. Reductions in these new neurons have even been associated with depression.
However, after exercise, new neurons in the hippocampus have been shown to grow more and survive for longer, allowing them to contribute to existing neural pathways. This effect can even be seen at the level of the entire brain, as brain volume increases in elderly individuals who participate in physical exercise. Communication between neurons is also improved, a change associated with an increase in blood supply to the areas of the brain needing it the most.
Conversely, the effects of meditation on the brain are a lot less studied. Mindfulness is defined as exercising non-judgmental awareness of present experiences and, similar to exercise, has been shown to increase well-being. People practising mindfulness show increased levels in attention and emotional regulation. Again, corresponding changes in the brain can also be observed. Our consciousness is a constant stream of thoughts and ideas and can be directed to specific tasks when required. But, in the absence of these tasks, one particular network is active: the default mode network (DMN).
The DMN is like a screensaver, generating activity and random thoughts until a specific network is required for a given task. Changes in the brain associated with mindfulness appear to focus on the DMN, increasing the activity of brain regions involved in attention. This appears to fit with the concept of mindfulness, as it actively seeks to change awareness of the present, particularly in the absence of any tasks being undertaken.
Areas involved in emotional processing also appear to be altered after participants practised mindfulness exercises. In a way, exercise and mindfulness appear to be two sides of the same coin. Exercise is conducted for a host of different reasons, such as staying fit or losing weight, but the great changes seen in the brain appear almost as a side effect. They explain why we feel better after exercising and why cognition is increased.
Unintentionally, basic pathways, such as memory formation, are changed for the better as an additional benefit to staying healthy. The practice of mindfulness, on the other hand, solely focuses on mental processes and how they may be actively changed. The brain appears to be able to respond to both inputs, signals from the body during exercise and mental stimuli during mindfulness practices, and the final output is an increase in happiness.
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