Brain health and exercise

Our brain is the most complex organ in our body and the command centre of our nervous system.  Preserving optimal brain health is one of the the most important goals in improving healthspan and lifespan. The human brain enables all our movements, automatic behaviour, emotions, thoughts, decisions, memories, sensation perception and regulation of organ function. Nobody wants to live a long life without maintaining brain health. 

Brain health preservation is complex and includes:

- maintaining brain structure and volume

- preserving brain functions such as learning, reading, language, problem-solving and memory

- preserving mental function which includes the processing of feelings, thoughts and perception

 - absence of brain diseases which affect normal brain function including Alzheimer’s disease, mental health disorders (e.g. depression and anxiety), stroke and traumatic brain injuries.

As we age changes occur throughout our body including our brain. The causes of brain health decline include:

• shrinking of certain parts of the brain, particularly those associated with learning and memory;

• degradation of communication between the brain’s cells (neurones);

• reduced blood flow to the brain (blood flow is critical in transporting oxygen and fuel to the brain;

• increase in inflammation (neuroinflammation).

However, our brain health is not definitely going to decline as we age, we have control over our lifestyle factors which we can modify to protect brain health.

There are numerous ways in which we can help keep our brain healthier for longer:

• Exercise and and keeping physically active

• Doing activities which boost cognitive reserve - learning a new skill, language, music, exercise

• Having a healthy diet - generally a ‘heart healthy’ diet is one which is also good for your brain

• Constantly getting sufficient, good quality sleep

• Maintaining positive social connections

Being physically active and getting regular exercise is proven to be one of the most powerful tools to maintain brain health.

From the age of approximately 40 onwards, and more so at age 70, crucial parts of the brain begin the shrink. These include the areas of our brain involved with memory, emotions, social interaction, motor function and language. Regularly engaging in physical activities such as walking, running or sports improves brain volumes, particularly those areas which are important for memory and learning. Numerous studies have shown the stark difference in brain volume between sedentary and active older adults. Although the specific mechanisms underlying this positive relationship between physical activity and brain volume are not yet fully understood, the relationship has been proven in multiple studies. 

Perhaps the most obvious way in which exercise benefits brain health is through increasing blood flow to the brain. As we age blood flow to the brain typically reduces. Having good blood flow is critical to supplying the brain with oxygen and energy. Incorporating aerobic exercise (for example going for long, brisk walks) into your daily routine increases cerebral blood flow, therefore counteracting the reduction in brain health caused by reduced blood flow.

Physical activity also increases certain growth factors which play an important role in neurone growth and survival - neurotrophic growth factors. These include brain-derived neurotrophic factor (BDNF),  insulin-like growth factor (IGF-1) and vascular endothelial growth factor (VEGF). These factors mediate numerous specific and overlapping neuroprotective effects. For example, BDNF increases the generation of functional neurones (neurogenesis) and boosts the brains ability to adapt and learn (neuroplasticity) therefore delaying brain ageing and improving symptoms of depression.

Exercise has been shown to reduce pro-inflammatory and enhance anti-inflammatory cytokines. As we have discussed previously, systemic low-grade inflammation is a common feature of many of the chronic diseases of ageing including Alzheimer’s Disease (AD) and is correlated with cognitive decline. Exercise directly improves brain health and cognitive function through inhibiting neuroinflammation. However it also has the remarkable effect of also improving the various indirect risk factors for cognitive decline - high blood pressure, elevated glucose levels, insulin insensitivity and dyslipidaemia.

Another mediator which has recently been identified as a key link between increased physical activity and reduced AD risk and cognitive decline with age is the hormone Irisin. Irisin is secreted by muscles during exercise and has direct effects on the brain such as protection from neuroinflammation. 

Although not a normal part of ageing, the risk of AD is greatly increased with ageing and currently affects over 25 million people worldwide. Getting regular exercise reduces your risk of AD by some 45%.

It also improves cognitive function in patients with AD. Apart from the pathways mentioned above, exercise also reduces amyloid beta concentration and inhibits tau phosphorylation (two of the main pathological hallmarks of AD).

Stroke is another major threat to brain health and is one of the leading causes of morbidity and mortality. Exercise is well-known to have a multifactorial effect on decreasing stroke risk. Furthermore, exercise and physical activity are useful tools in rehabilitation and maximising functional recovery of stroke survivors. 

Mental health disorders are currently on the rise globally. The positive effects of getting regular exercise are perhaps most obvious on this aspect of brain health. The release of serotonin and endorphins during exercise enhance mood almost instantaneously. But also in the long-term being regularly physically active reduces your risk of depression, anxiety and other mental disorders through a variety  of different mechanisms.

The numerous benefits of exercise on brain health is undeniable. From slowing down natural age-related brain decline to reducing your risk of mental disorders and neurodegenerative diseases, exercise exerts its neuroprotective effects through multiple direct and indirect pathways. no matter what age or fitness level, getting regular exercise helps.

 If you would like have a personalised review of your lifestyle and to test your personal risk factors for developing chronic diseases of ageing, find out more about the Longevity Annual health check and download the longevity doctor guide to healthy living.