Let’s Get Physical
Building & Connecting the Brain Through Exercise.
The intricate relationship between physical exercise and brain health is a subject of growing interest in the scientific community. Research consistently shows that regular physical activity, particularly heart-pumping aerobic activity, is related to cognitive function, mental well-being, and overall brain health.
Guidelines from the Canadian Society for Exercise Physiology recommend at least 150 minutes of moderate- to vigorous-intensity aerobic activity weekly, coupled with strength and balance exercises. What we don’t yet know are specifics about who benefits the most and how we can tailor exercise to maximize benefits.
Evidence suggests that the brain responds differently to exercise across the lifespan and varies based on individual factors like biological sex and genetics.
These connections are underpinned by complex physiological and psychological processes that affect how the brain operates and adapts to various stimuli.
This article explores the transformative effects of exercise on the brain, incorporating insights from Dr. Cindy Barha, assistant professor in the Faculty of Kinesiology at the University of Calgary, Canada Research Chair (Tier II) in Neuroscience, Brain Health and Exercise, member of the Hotchkiss Brain Institute, and the first Women’s Brain Health Initiative Future Leader in Canadian Brain Research. Future Leaders in Canadian Brain Research is one of Brain Canada’s signature capacity building programs and has funded more than 100 early career researchers to date.
“Brain Canada is thrilled to see how our signature Future Leaders program has grown, enabling us to provide increased support to researchers during this pivotal stage of their careers,” said Dr. Viviane Poupon, President and CEO of Brain Canada. “As a leading research funder focused specifically on the brain, we are thrilled to advance the field of sex and gender brain science and support Dr. Barha’s work, together with our partner, Women's Brain Health Initiative.”
EXERCISE AS A CATALYST FOR NEUROGENESIS & STRUCTURAL CHANGES
One of the most groundbreaking discoveries in neuroscience is the brain’s ability to generate new neurons, a process known as neurogenesis, in adulthood. Exercise plays a pivotal role in this phenomenon, specifically in the hippocampus, a brain region associated with memory and learning.
A 2024 review published in Trends in Neurosciences by Dr. Nárlon C. Boa Sorte Silva and colleagues presented evidence from systematic reviews and meta-analyses showing that physical activity promotes structural and functional brain adaptations, such as increased gray matter volume and enhanced white matter integrity.
Dr. Barha, a co-author on this review, highlighted, “When it comes to healthy aging, brain adaptations linked to exercise not only improve memory but also enhance higher-order cognitive functions, such as the brain’s capacity to manage multiple tasks simultaneously.”
The review further highlighted that brain changes were seen in healthy individuals and those with mild cognitive impairment, though effects were modest.
When comparing the effects of different types of exercise in the brain, aerobic exercises (e.g., running, cycling, and swimming) emerge as particularly effective in supporting neuron growth and survival via the production of brain-derived neurotrophic factor (BDNF).
As it turns out, when your heart pumps faster and increases blood flow during physical activity, there are corresponding increases in proteins like BDNF delivered to the brain and made within the brain.
BDNF IS LIKE A VITAMIN FOR YOUR BRAIN. REGULAR PHYSICAL ACTIVITY BOOSTS ITS LEVELS, CREATING AN ENVIRONMENT WHERE NEURONS CAN THRIVE, AND CONNECTIONS CAN STRENGTHEN. THIS IS CRUCIAL FOR MAINTAINING COGNITIVE VITALITY AS WE AGE.
BOOSTING COGNITION
THROUGH MOVEMENT
In addition to neurogenesis and structural changes, BDNF can also support cognitive functions such as focusing attention, planning tasks, ignoring distractions, and consolidating memory.
A 2019 review of research by Dr. Magdalena Miranda and colleagues from the Laboratory of Memory Research and Molecular Cognition in Argentina explained that aging, development of Alzheimer’s disease (AD), and chronic stress can decrease levels of BDNF, however, exercise can elevate BDNF and enhance cognition both during and after a bout.
Published in Frontiers in Cellular Neuroscience, the evidence showed that BDNF is elevated rapidly during exercise, stays consistent with regular exercise, and remains elevated for several days.
Furthermore, interventions that combine exercise with cognitive demands may have the greatest impacts on the brain. For instance, cited research showed that a dancing program that required more coordination and cognitive processing resulted in greater increases in gray matter than a traditional sports program.
Different types of exercise training appear to influence different types of brain function.
Dr. Barha and colleagues examined the types of exercise protocols used in randomized controlled trials in older adults and their effects on the brain.
Their influential 2017 review and meta-analysis in Frontiers in Neuroendocrinology, which has been cited by both the WHO Guidelines on Risk Reduction of Cognitive Decline and Dementia and the Lancet Commission, showed that aerobic training, resistance training, and multimodal training that combined aerobic and resistance training all enhanced visuospatial function (e.g., distance perception) and executive functions, but only multimodal training improved episodic memory (e.g., recall events and experiences).
Moreover, aerobic training was more beneficial for global cognitive function and executive functions than resistance training, and multimodal training was even better than aerobic training across several areas: global cognitive function, episodic memory, and word fluency.
These findings align with the Canadian physical activity guidelines recommending that older adults should engage in combinations of aerobic, strength, and balance exercises.
THE ROLE OF EXERCISE IN NEUROPROTECTION IN MID-LIFE
Exercise acts as a powerful neuroprotective agent with multi-system effects like reducing inflammation, lowering oxidative stress, and improving vascular health. These benefits contribute to brain resilience and offer hope for those at risk of or living with neurodegenerative conditions.
“Exercise strengthens the brain’s defences,” Dr. Barha asserted.
EXERCISE PREVENTS DAMAGE AND AIDS RECOVERY FOR INDIVIDUALS WITH BRAIN INJURIES AND CAN SLOW DOWN DAMAGE FROM NEURODEGENERATIVE DISEASES.
One important consideration highlighted by Dr. Barha is that brain health status can impact exercise levels. People with cognitive impairments can have challenges with organizing their time, planning exercise into their day, setting goals, and adhering to exercise recommendations.
A 2017 study by Drs. Varma and Watts in Journal of Alzheimer’s Disease showed that daily physical activity levels declined among people in early stages of AD prior to any declines in mobility and physical function.
Building social supports into exercise programs (e.g., exercise buddies or group classes) or creating exercise programs that can be done with caregivers or family members from the earliest signs of cognitive impairments might help to promote exercise adherence and slow down the progression of disease.
Exercise indirectly benefits brain health as well by preventing and mitigating effects of diabetes and hypertension, known risk factors for neurodegenerative diseases.
Efforts to prevent these chronic conditions takes on greater importance when adults approach mid-life, and this may be especially the case for women.
“Mid-life, that is, about age 45 to 60, is a critical window for intervention because it is a critical window for brain vulnerability,” explained Dr. Barha.
When it comes to women, around mid-life, they typically go through perimenopause where there are fluctuations in hormone levels like estradiol, and changes in neuroinflammation and even changes in the brain’s energy sources that can damage the brain’s white matter can start to be seen.
“By intervening in mid-life, we can hopefully use exercise to bolster the brain and reduce damage, reduce risk for dementia or severity of dementia later in life,” said Dr. Barha.
SEX DIFFERENCES IN EXERCISE & BRAIN HEALTH
Although we know that exercise is beneficial for brain health, there are some inconsistent findings, that is, variability in outcomes like memory and executive function. As Dr. Barha explained, “The source of variability between studies could be related to the who, the what, and the how of exercise.”
In Dr. Barha’s lab, they are focusing on the “who” sources of variability in brain health outcomes from exercise by looking at sex differences between males and females, and how previous reproductive experiences change the way the female brain ages, as well as how the brain responds to exercise as an intervention for cognition.
Few studies have looked at the ways that biological sex influences the brain’s responses to exercise, and even fewer studies have been done on women only, posing challenges for understanding how men and women’s brains respond to exercise.
In her 2017 meta-analysis in Frontiers in Neuroendocrinology, data showed that while exercise enhanced executive functions for both older men and women, there were larger effect sizes in studies with a higher percentage of women in the sample. She’s also found this same sex difference favouring women across populations and study designs.
THIS SUGGESTS THAT PHYSICAL ACTIVITY IS MORE PROTECTIVE OF COGNITION IN WOMEN THAN IN MEN, AND THAT WOMEN MAY BENEFIT MORE FROM BEING PHYSICALLY ACTIVE THAN MEN.
In a follow-up study, Dr. Barha has shown that this may be related to a greater increase in the brain “vitamin” BDNF from exercise in women compared to men.
Reproductive history also plays a role in how the brain ages, lifetime risk of developing dementia, and how the brain responds to exercise.
“When looking at studies with older women, it’s fascinating that pregnancy experiences from decades earlier have changed their brains in such a way to put certain groups – women who have had five or more complete pregnancies (multiparous), and women who have had zero complete pregnancies (nulliparous) – at higher risk of developing dementia,” shared Dr. Barha.
Fortunately, these data published in The Journals of Gerontology Series A in 2023 have shown the strongest positive relationships between physical activity levels and cognition for multiparous and nulliparous women, suggesting that exercise as an intervention could be most effective in these two at-risk groups.
As we learn more about these interactions, targeted exercise interventions and specific exercise recommendations for nulliparous and multiparous women later in life could help to mitigate risks of cognitive decline.
Dr. Barha explained, “We are trying to fine-tune and understand which groups need to be targeted, which groups are most at risk for cognitive decline and brain health decline, and how we can best support their brains as they age.”
As the body of research grows on biological sex, exercise, and brain health, Dr. Barha is hopeful that more personalized recommendations for exercise will emerge based on combinations of factors.
JUST DO IT
Though we do not yet know the exact dose, type, and timing of exercise needed to maximize cognitive benefits, research clearly shows that there is a positive relationship between exercise and brain health.
From neurogenesis to neuroprotection, regular physical activity serves as a cornerstone for a resilient, healthier brain, and all movement is cumulative and beneficial.
“You just have to move your body,” advised Dr. Barha. “Any movement counts, and you need to incorporate it into your everyday life.” Whether it’s a daily walk or joining a community fitness class, the key lies in consistent, enjoyable movement to support your brain.
Dr. Barha’s WBHI Future Leader in Canadian Brain Research grant is made possible by the Canada Brain Research Fund, an innovative arrangement between the Government of Canada, through Health Canada, and Brain Canada, and WBHI.
Source: Mind Over Matter V20