Brain Gains: Could Weight Training Prevent Alzheimer’s Disease?
How much do you lift (bro)? If I asked this question a decade ago, most probably only a small proportion of people would raise their muscle-born arms. But with the rise of social media platforms like Instagram and their #fitfam, many individuals are incorporating shifting timber into their workout routines. And although the majority lift weights to improve their physique, the benefits of strength training potentially stretch much further than a six pack and tight hamstrings. In fact, regular resistance-based workouts could potentially fight off one of the world’s biggest killers: Alzheimer’s disease. New research argues practicing leg and chest pressing could prevent death of brain cells in regions involved in the most common form of dementia, suggesting resistance training could also allow your brain to resist neurodegeneration.
What is Alzheimer’s disease?
Alzheimer’s disease is the most common form of dementia; a condition which affects almost 50 million people around the globe. Dementia is now the main cause of death in the UK and the lack of therapeutics means numbers are predicted to hit around 150 million by 2050 worldwide. Alzheimer’s disease normally occurs in people over the age of 65 and results in loss of memory, which worsens over time. This memory loss is a result of the death of brain cells in the brain region known to be crucial for forming long-term memories: the hippocampus. The hippocampus suffers drastic cell loss during Alzheimer’s disease which is followed by brain cell loss in frontal brain regions – associated with ‘higher’ human functions like attention, problem solving and inhibitions. At present, we do not have an affective therapeutic to combat Alzheimer’s disease and approximately 99% of cases appear to occur ‘randomly’ (i.e. not caused directly by a mutation in an individuals DNA). Therefore, we really are on a precipice of a world overran with individuals suffering from this and other heartbreaking neurodegenerative conditions.
Feel the Burn: Could Resistance Training Resist Brain Cell death?
As the majority of Alzheimer’s cases are not directly caused by the genes inherited by parents, it is believed certain lifestyle factors can contribute towards contracting the disease later in life. Behaviours such as smoking and social isolation, as well as obesity and diabetes have been linked to increasing the risk of developing Alzheimer’s disease. One of the more studied lifestyle factors associated with preventing Alzheimer’s disease is exercising. A study comparing the risk of developing Alzheimer’s in the general population revealed that physical inactivity is the number one risk factor for going on to develop the disease.
Studies revealing correlations between two factors are very valuable but in order to really understand if these factors are linked, we need to learn more about the actual alterations exercise could be having on the brain to prevent Alzheimer’s. A study published in January 2020 decided to look at how long-term resistance training (weight lifting-type exercises) affected the hippocampus in the brains of those with mild cognitive impairment (MCI). People with MCI struggle remembering recent events and higher functions like judgement are impaired, but not enough to interrupt their day to day life significantly. Individuals with MCI have an increased risk of going on to develop dementia and brain scans of MCI patients have shown they have reduced hippocampus volume compared to healthy controls, indicating brain cell death in this memory-forming region.
The current study took 100 MCI patients and subjected a subset of them to 6 months of a resistance training routine, and half of these patients also received cognitive training alongside their weight workouts. A year after the 6 month training had ceased, the individuals who had participated in the resistance training routine had a significant reduction in hippocampal brain cell loss compared to MCI patients on no exercise, irrespective of cognitive training. These individuals also had, on average, a better cognitive scoring dependent on hippocampal volume and their activity in the year following the training did not impact the results of the study. The conclusions of this research suggests regular resistance training could thwart Alzheimer’s development by preventing the loss of brain cells in the hippocampus.
Could Pumping Iron Really Stop Alzheimer’s Disease Development?
The results of this latest study certainly strengthens the link between exercise participation and reduced chance of developing Alzheimer’s. Rather than just observing a relationship like more exercise = less Alzheimer’s, the researchers have pinpointed a potential brain mechanism this type of exercise might affect; preventing death of brain cells in the hippocampus. What we still do not get from this study is how exercise potentially prevents hippocampal tissue loss. If we can establish the steps in-between bench press to brain protection using lab-based models, these discoveries could be highly useful for therapeutics and even make prescribing exercise a possibility for those at risk. In addition, MCI only makes an individual more likely to go on to develop dementia rather than being a definitive predecessor to the disease. Therefore, the individuals in this study who exercised and showed less atrophy could have been members of the MCI cohort who would not have gone on to develop a dementia anyway. It will be interesting to follow all the patients who participated in the study over the next decade to see how many develop Alzheimer’s or another dementia and correlate this development with exercise training.
Alzheimer’s disease and other neurodegenerative diseases are becoming more and more common in our ever-ageing population, with cures for other conditions like cancer and heart disease leading to an indirect increase in those individuals ending their lives with a dementia. The influence our lifestyle has on the development of the disease is obviously from the low proportion of genetic cases, but pinpointing what these ‘bad influences’ are is tricky. Research is pointing towards exercise being useful in preventing these neurodegenerative conditions, and now it looks like resistance training could protect the ‘ground zero’ of Alzheimer’s disease, the hippocampus, from losing brain cells. So it might hurt your muscles to pump some iron a few times a few, but it won’t hurt your brain!
Julia xoxox (@Julia.ravey.science)
For more on Alzheimer’s disease, see my website and this review looking at Alzheimer’s and exercise. Plus I have a new YouTube Channel talking all things Brian – check it out!