Posted on 03 May 2024

We often think about exercise in helping our physical wellbeing, changing our body, losing weight and getting fitter. But more and more, as time goes on, it is becoming increasingly apparent that exercise also benefits our brain greatly. It is thought that physical activity helps protect against premature brain ageing, which has links to diseases like Alzheimer’s and Parkinson’s; we may need to begin to shift our view of exercise into a more holistic lens, one that benefits all of our body and not just our organs and heart.

In a recent long-term study, a cohort of 454 elderly individuals underwent annual physical examinations and cognitive evaluations over a span of two decades, followed by posthumous brain donation to allow researchers to analyse the brain closely on autopsy. At the same time, participants were outfitted with accelerometers to monitor their daily physical activity levels. Analysis of the longitudinal data revealed a significant correlation between heightened physical activity levels and superior performance on memory and cognitive assessments. Furthermore, escalations in physical activity were linked with a noteworthy 31% decrease in the risk of dementia and, importantly, this association persisted even after meticulous adjustment to account for participants' neuropathological profiles and dementia status.

In a parallel interventional inquiry, 160 sedentary older adults experiencing mild cognitive impairment were allocated various lifestyle interventions to follow. These interventions included engagement in aerobic exercise sessions thrice weekly, adhering to a heart-healthy Dietary Approaches to Stop Hypertension (DASH) regimen, combining aerobic exercise with the DASH diet, or receiving health education as a control measure. Over the course of a six-month intervention period, individuals adhering solely to the DASH diet did not exhibit advancements in executive function (responsible for cognitive processes such as planning, problem-solving, and multitasking), and participants in the health education group demonstrated a decline in brain function. The study findings indicated moderate to high intensity exercise might be most effective in preserving cognitive function – but even long walks can suffice.

“When you’re working out at moderate intensity, that’s working out to the point where you’d be able to talk but not sing during your workout. When we’re talking high-intensity effort, that’s the point that you’re exerting yourself such that you’re not able to say more than a few words without pausing for a breath,” Dr. Ross, a physical therapist, explains.

“There are a lot of potential mechanisms of exercise that may be combining to benefit brain health,” Dr. Bonner-Jackson, a neuropsychologist says. “In general, even in people who are at risk for development of Alzheimer’s or other dementias, can stave off decline in some cases for many years and help people function better.”

These long-term studies are vital for attaining a multigenerational picture of what works to protect brain health, and join an ocean of research worldwide that seeks to explain both how and in which ways physical activity benefits the brain – helping us to understand exactly how exercise can help to preserve memory and stave off early cognitive decline, such as through:

  • Promoting cardiovascular health

  • Improving blood flow to the brain

  • Reducing inflammation, and

  • Lowering levels of stress hormones, which can cause damage after long-term exposure.

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