Exercise and the Brain: How Physical Activity Guards Against Alzheimer’s
As dementia rates continue to climb, the scientific community is relentlessly exploring avenues to shield our brains from cognitive deterioration.
Alzheimer's disease, a particularly harrowing neurodegenerative disorder, afflicts nearly one million individuals in the UK alone, emphasising the pressing need for effective preventive strategies. Recent discoveries have spotlighted a powerful weapon in this battle: exercise.
The Power of Movement
The Alzheimer’s Society recently analysed 11 studies examining the relationship between lifestyle changes and brain health in our golden years. Their conclusion?
Exercise stands out as the most potent defence, slashing dementia risk by up to 45%. The question arises: what makes exercise such a potent shield against dementia?
A groundbreaking study published in the journal Neuron offers some answers. It reveals that exercise triggers the release of a hormone called irisin. This hormone is a formidable foe against the toxic amyloid plaques in the brain, which are implicated in Alzheimer’s disease.
Christiane Wrann, an assistant professor of medicine at Harvard Medical School, explains, “Irisin helps reduce these plaques. It might have effects on cognitive function, neuroinflammation, clearing plaques, and also encouraging the formation of new neurons in the brain.”
The Cardio Connection
But irisin isn’t the sole hero in this narrative. Exercise, particularly aerobic exercise, bolsters cardiovascular health, which is intrinsically linked to brain health. Michael Hornberger, a professor of applied dementia research at Norwich Medical School, emphasises the age-old wisdom: "What’s good for the heart is good for the brain."
This connection is more than just an adage. The brain is a voracious consumer of our blood's oxygen and sugar. A healthy cardiovascular system ensures that the brain receives the nourishment it needs. Some dementias, like vascular dementia, are directly tied to impaired blood flow to the brain. A 2019 study from Lund University further supports this, showing that middle-aged individuals who engaged in regular physical activities like skiing or running had a reduced risk of vascular dementia later in life.
Beyond Blood Flow
Andrew Budson, professor of neurology at Boston University, introduces another player in this intricate dance: brain-derived neurotrophic factor (BDNF). This molecule, released during vigorous exercise, aids in neuron regeneration and activation, especially in memory-centric regions like the hippocampus. Budson cites a 2011 study where older adults who focused on enhancing their fitness witnessed a surge in BDNF levels, hippocampal size, and memory performance.
The Ideal Exercise Regimen
So, what's the best exercise prescription to shield our brains from Alzheimer’s? Budson recommends activities that elevate the heart rate: running, swimming, vigorous walking, cycling, or sports like tennis and badminton. While casual strolls offer health benefits, it's the more intense activities that deliver significant brain-boosting effects.
Strength training, though crucial for balance and preventing frailty, is still under investigation for its direct brain-protective effects. However, as Hornberger points out, it can elevate the heart rate and safeguard against falls, which can lead to hospitalisations detrimental to brain health.
As for the ideal amount? Aim for at least 30 minutes of aerobic exercise five days a week. A 2022 study in JAMA Neurology even quantified the benefits, suggesting that around 10,000 steps daily could halve the risk of Alzheimer’s.
The Future: An Exercise Pill?
The concept of an exercise pill, encapsulating the benefits of physical activity, has transitioned from science fiction to a tangible research goal. Wrann and her team are exploring the potential of a synthetic version of irisin as a therapeutic agent against neurodegenerative diseases.
With the looming threat of dementia in our aging population, understanding and harnessing the power of exercise could be our best defence.
While the promise of an exercise pill is exciting, for now, the best prescription remains the age-old advice: stay active. As Wrann aptly puts it, "Even if you can do 10 minutes per day, that will still be beneficial to your body and mind in some way."
Frequently Asked Questions (FAQs)
1. How does exercise reduce Alzheimer’s risk?
Exercise releases the hormone irisin, which can clear toxic amyloid plaques in the brain. Additionally, exercise improves cardiovascular health, which is crucial for brain function.
2. What type of exercise is most beneficial?
Aerobic exercises that elevate the heart rate, such as running, swimming, or cycling, are the most effective.
3. How much exercise is recommended?
Aim for at least 30 minutes of aerobic exercise five days a week. However, even shorter durations can still offer benefits, as emphasised by experts.
4. What is the potential of an exercise pill?
Scientists are exploring the possibility of a pill that mimics the benefits of exercise, particularly focusing on the hormone irisin.
This article is for general information only and is not intended to treat or diagnose medical conditions. If in doubt please check with your GP first.