Exercise to keep your brain sharp

The benefits of physical exercise for decreasing mortality and morbidity and improving physical function are well-established. Many studies now also support the link between the practice of regular exercise and cognitive brain health in older adults.

Did you know?


Regular physical exercise is strongly connected to the maintenance of cognitive brain health.1


Good brain health is a key factor in maintaining independence in the elderly, and is the top health-related concern amongst many older adults.2


An opportunity therefore exists for health professionals to prescribe regular exercise as a “medicine” to promote healthy cognitive aging.3


A systematic review and meta-analysis of lifestyle factors (e.g. smoking, alcohol, caffeine, nutrition, physical activity) and cognitive function found that physical activity was one of the strongest predictors of reduced risk for Alzheimer’s disease.4

The Facts:


The neurobiological foundations for cognitive improvements brought about by exercise include the ability to: counteract age-related atrophy of grey and white matter in the brain5-7; increase the blood supply, dendritic spine density and complexity of the hippocampus; enhance synaptic plasticity8; and increase the release of neurotrophins and trophic factors that enhance neuronal growth and survival.9-11


Cerebral blood flow 

  • Regular physical exercise supports cognition by maintaining and improving cerebral blood flow, which decreases by about 30% between midlife and old age, and has been linked to age-related brain atrophy.1
  • One 12-week study found that one hour of moderate-intensity aerobic exercise, three times per week, increased cerebral blood flow in the bilateral anterior cingulate cortex (ACC) area of the brain. People who exercised also showed greater gains in brain function and cognition than those who didn’t.12

Brain volume

  • The aging brain undergoes selective atrophy, mainly in the regions called the prefrontal cortices and medial temporal lobes.13, 14
  • Beginning at about age 50, the hippocampus shrinks 1 to 2% every year in healthy older adults.13 These reductions in hippocampal volume have been associated with decreased memory, processing speed and executive function.15, 16
  • Higher levels of cardiorespiratory fitness have been linked to larger brain volumes, particularly the hippocampus and prefrontal cortex. These areas may preserve memory, improve cognitive performance and protect against dementia in older adults.17, 18
  • A 6-month intervention of both low- and high-intensity aerobic exercise was associated with increased neuron density and volume in the hippocampus.19
  • Another study of healthy elderly subjects found that those who engaged in either medium-intensity exercise (Nordic walking) or low-intensity exercise (gymnastics) had a greater increase in the volume of grey matter than those who didn’t exercise.1,5

Connectivity

  • Connectivity between brain hemispheres decreases with age, contributing to cognitive decline.20
  • Studies have reported that exercise is associated with greater connectivity in the brain, leading to improved executive control. This effect is observed with higher intensity short-term interventions (16 weeks), light to moderate aerobic exercise (6 months), and long-term exposure to exercise (1 year).21-23

Trophic factors

  • Several trophic factors have been identified to support cognition in aging adults.
  • The most commonly discussed factors that support cognition include:
    • brain-derived neurotrophic factor (BDNF)
    • vascular endothelial growth factor (VEGF)
    • insulin-like growth factor-1 (IGF-1)

These trophic factors work together to support the development of neurons and stimulate blood vessel growth to nurture the creation and preservation of neurons and neuronal function.24

  • Moderate-load resistance (or strength) training followed by moderate- to high-intensity aerobic training, or a combination of aerobic, strength and coordination training, increase the levels of BDNF in the brain, with improvements in short-term memory and processing speed.25, 26

What can we do about it?


Since exercise changes the brain in ways that protect memory and thinking skills, it is recommended that people from all ages regularly engage in physical activity. 27


Move safely:

Physical activity is important, but it is also important to minimise the risk of injury or other issues by doing it safely

  • Almost anyone can be safely active, if you understand the risks and work with them.
  • Start by choosing activities that suit your fitness level and health goals.
  • If you are currently inactive, choose low-intensity activities and then gradually build them up by moving for longer and more often.
  • Increase your activity levels gradually over time until you meet the recommended guidelines, or those recommended by your doctor or health professional.
  • Use the right equipment and follow the rules and recommendations to protect yourself from injury or further health issues. Choose safe environments, activities and times to be active.
  • Consult a health professional if you have chronic health conditions or symptoms, and work with them to find the best types and amount of activity for you.

Follow the recommended guidelines for physical activity:

  • We all need to move more and sit less during our day. Even getting up for a glass of water or a stretch is better than remaining sitting.
  • Adults should do at least 30 minutes of moderate-intensity or 15 minutes of vigorous-intensity aerobic physical exercise on most days. Children should spend double this time.
  • Older adults should be as physically active as they are able and their conditions allow, if they are unable to meet these guidelines.
  • Increasing the time or intensity of activity can provide extra benefits to health and fitness.
  • Developing muscular strength by doing resistance training should be included at least twice per week. Older adults should also include balance activities.
  • Activities that develop flexibility, balance, coordination, proprioception and other neuromotor skills are also beneficial as part of an overall program.

Adults:

  • Any increase in activity or reduced time sitting will bring health benefits.
  • To get significant health benefits adults should spend a minimum of 150 minutes (2.5 hours) per week doing moderate-intensity physical activity, or 75 minutes (1 hour 15 minutes) doing vigorous-intensity aerobic activity, or a combination of both. Preferably, this activity should be spread throughout the week.
  • Doubling these times will bring additional benefits.
  • Being physically active (moderate-intensity) for more than 300 minutes (5 hours) per week will bring greater benefits again.
  • Moderate or greater intensity muscle-strengthening activities involving all major muscle groups are also important at least twice per week

Older adults:

  • Among older adults, proper physical activity can increase and maintain physical function, improve and maintain body composition, promote psychological and cognitive well-being, and assist in primary and secondary prevention of chronic diseases.
  • Older adults should include balance training, aerobic and muscle-strengthening activities in their regular physical activity.
  • Examples of balance exercises include walking sideways and backward, repetitively standing and sitting, standing with eyes closed, etc.
  • Older adults who are unable to complete 150 minutes of moderate-intensity aerobic activity each week should be as physically active as they can, within the limits of their abilities and conditions.
  • Inactive seniors may benefit from working with an exercise physiologist or credentialed personal trainer, particularly when first starting an exercise program.

Summary:

To prevent cognitive decline and keep the brain sharp for as long as possible, regular exercise is one of the top lifestyle factors that have been shown to improve cognitive abilities. People from all age groups should participate in a well-rounded, regular exercise program that suits their preferences, fitness level and medical condition.

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Dr. Luiz Fernando SellaMD, MPH
Author
Medical Doctor at the Federal University of Santa Catarina, Brazil, a Certified Lifestyle Medicine Physician and Health and Wellness Coach.