So let me ask you a question. What is the best primary modality to thwart the development and progression of neurodegenerative diseases such as Alzheimer’s dementia? Well, if you missed my blurb on The Today Show last Friday, allow me to fill you in: Exercise. Surprise, surprise.
What if I told that strength training is predominantly a mental activity? Just think about it (no pun intended). What is the stimulus for muscular contraction? Will. Volition. An impulse generated in the brain’s premotor cortex. How? We have no idea. Likely it’s a quantum phenomenon, but that’s neither here nor there. Bottom line: you are exercising your brain through the direct extension of your central nervous system, your muscles! Your will is exerted through you muscles. Without the will to squat 400 lbs for example, there is no squat. You will unceremoniously be pinned to the ground by the loaded bar. A weak mind equates to failed execution and well…weakness.
And the converse is true. Training with high intensity requires mental fortitude, focus and motivation to forge through the associated bodily discomfort. Cumulatively, these factors amongst others exert “neuroprotective” effects on the brain (in addition to catalyzing physical and functional gains). And that’s what has borne out in recent studies.
One such study published in Frontiers in Aging Neuroscience demonstrated that hippocampal volume in patients genetically predisposed to Alzheimer’s disease was maintained in those engaged in high levels of physical activity. Yes, the expected decrease in size of the brain’s memory hub (hippocampus) in those genetically predisposed to Alzheimer’s disease was not seen in the cohort who exercised regularly. In the sedentary cohort of study patients, a 3% decrease in hippocampal volume was noted. And that’s a costly depreciation in real estate in case you were wondering. Even small reductions in volume equate to clinically apparent memory loss.
Take-home message? Even in those genetically predisposed individuals, high levels of physical activity can thwart the neurodegenerative process. A second similar study published in the British Journal of Sports Medicine demonstrated significant enlargement of the hippocampus in 86 exercised women with mild cognitive impairment (MCI), a potential harbinger of later dementia. And while it may seem odd to consider that one can readily effect changes in his or her brain through regular exercise, remember this:
- Exercise increases production of brain-derived neurotrophic factor or BDNF which augments neurogenesis and neuron-to-neuron connectivity.
- Exercise exerts potent anti-inflammatory effects.
- Exercise increases cerebral blood flow which may, like sleep, clear potential neurotoxins from the brain.
- Exercise also improves insulin sensitivity, mitigating this risk factor for neurodegenerative disease.
And the list goes on and on…
So stack the odds in your favor by exercising regularly (5 days per week). Alzheimer’s disease is to a great degree preventable, yet another environmental disease in the same category as coronary and cerebrovascular diseases, cancer and type II diabetes. You are not destined to become demented even in the context of unfavorable genes. That’s what the data suggests. You are in control, not your DNA! And exercise is one of the few modalities that allow you to exert such control. The adaptive response to the imposed stresses of exercise makes us better, plain and simple. Body and mind. It used to be said that “what doesn’t kill you will make you stronger.” Maybe it should read, “What doesn’t kill you will make you smarter.”
Sources:
Brinke LF, et al. Aerobic exercise increases hippocampal volume in older women with probable mild cognitive impairment: a 6-month randomised controlled trial. Br J Sports Med doi:10.1136/bjsports-2013-093184.
Smith JC, et al. Physical activity reduces hippocampal atrophy in elders at genetic risk for Alzheimer’s disease. Front Aging Neurosci doi:10.3389/fnagi.2014.00061.