Being active, especially in nature, is part of our genetic programming and ensures our cognitive performance up to a ripe old age.

Physical exercise is an important part of a healthy lifestyle, contributing to general fitness, muscle control and coordination, and to a sense of wellbeing. Physical exercise is also essential for maintaining adequate blood flow to the brain and may stimulate brain cell growth and survival.  It can improve mood, prevent mobility problems and increase social interaction. 

For general physical health, research has shown that three types of exercise should be included in your regular routine:

  • Aerobic exercise:
    is any physical exercise of low to high intensity that depends primarily on the aerobic energy-generating process. “Aerobic” is defined as “requiring free oxygen”, and refers to the use of oxygen to adequately meet the energy demands of the cells during exercise (oxygen based metabolism). 
  • Strength or Resistance training:
    involves the performance of physical exercises which are designed to improve strength and endurance. It can be associated with the use of weights or using your own body weight.
  • Stretching or flexibility training:
    is a form of physical exercise in which muscles or tendons are deliberately flexed or stretched in order to improve the muscle’s felt elasticity and muscle tone. The result is a feeling of increased muscle control, flexibility, and range of motion.

Effects of physical exercise in dementia prevention [3]:

  • reduces oxidative stress and free radicals formation
  • reduces inflammation 
  • increases Amyloid ß clearance
  • improves glucose metabolism
  • enhances BDNF levels
  • helps to control stress
  • reduces risk factors for dementia: obesity, type 2 diabetes, hypertension

Many studies have found that physical activity in early, mid and late life is associated with higher intellectual function, lower risk of cognitive decline and dementia. Although all three types of physical activity have shown benefits in preventing dementia symptoms and treating mild cognitive decline, aerobic exercise is the most studied type to date.

It has been shown that aerobic exercise can improve attention, processing speed, executive function, memory and working memory in adults above 55 years without dementia. It can also improve cortical thickness and brain volumes, especially in frontal lobes and hippocampus [4].

One recent study [5] has demonstrated that the benefits of aerobic exercise in executive function and brain volume can be already documented  in young individuals (20 years old).

Conclusions:

Physical exercise has many health benefits and has been shown to improve brain functions and prevent cognitive decline. Aerobic exercise can improve brain volume and cognition. It is a relatively simple yet highly important factor to target, as it can easily be integrated into most people’s lives and may mitigate Alzheimer’s disease onset or progression. And you can’t start early enough!

Recommendations:

  • Regular aerobic exercise (ex. brisk walking, running, swimming, bicycling…) should be initiated early in life as part of the daily routine. Combining exercise and leisure is the most efficient way to maintain constant physical activity throughout life. 
  • Adults aged 65 years and above should do at least 150 minutes of moderate-intensity aerobic physical activity throughout the week, or do at least 75 minutes of vigorous-intensity aerobic physical activity throughout the week, or an equivalent combination of moderate- and vigorous-intensity activity (see table 1).
  • Adults of this age group with poor mobility should perform physical activity to enhance balance and prevent falls on 3 or more days per week.
  • Muscle-strengthening activities (ex. hatha yoga, bodybuilding, gymnastic…) should be done involving major muscle groups, on 2 or more days per week.
  • When adults of this age group cannot do the recommended amounts of physical activity due to health conditions, they should be as physically active as their abilities and conditions allow.
  • Physical exercise should be continued for as long as possible for people with dementia, as it has been found to have a number of benefits. It can help prevent muscle weakness, mobility problems and other health complications associated with inactivity. It can help promote a normal day-night routine, improve mood and increase social participation.
Light exerciseModerate exercise Vigorous exercise
Slow walkingFast walking (>4 km/h)Climbing stairs/hiking
Slow bicyclingBicycling (15 to 20 km/h)Bicycling fast (>20 km/h)
Standing, doing light workGardeningPlaying soccer
Doing office workSlow joggingJogging (> 9 km/h)
Table 1: Exercise levels and corresponding activities

References:

  1. WHO guidelines – Risk Reduction of Cognitive Decline and Dementia, 2019
  2. Garber CE, Blissmer B, Deschenes MR, Franklin BA, Lamonte MJ, Lee IM, Nieman DC, Swain DP; American College of Sports Medicine. American College of Sports Medicine position stand. Quantity and quality of exercise for developing and maintaining cardiorespiratory, musculoskeletal, and neuromotor fitness in apparently healthy adults: guidance for prescribing exercise. Med Sci Sports Exerc. 2011 Jul;43(7):1334-59.
  3. McGurran H, Glenn JM, Madero EN, Bott NT. Prevention and Treatment of Alzheimer’s Disease: Biological Mechanisms of Exercise. J Alzheimers Dis. 2019;69(2):311-338. 
  4. Raji CA, Merrill DA, Eyre H, Mallam S, Torosyan N, Erickson KI, Lopez OL, Becker JT, Carmichael OT, Gach HM, Thompson PM, Longstreth WT, Kuller LH. Longitudinal Relationships between Caloric Expenditure and Gray Matter in the Cardiovascular Health Study. J Alzheimers Dis. 2016;52(2):719-29.
  5. Stern Y, MacKay-Brandt A, Lee S, McKinley P, McIntyre K, Razlighi Q, Agarunov E, Bartels M, Sloan RP. Effect of aerobic exercise on cognition in younger adults: A randomized clinical trial. Neurology. 2019 Feb 26;92(9):e905-e916. doi: 10.1212/WNL.0000000000007003. Epub 2019 Jan 30. Erratum in: Neurology. 2019 Jul 23;93(4):185. PMID: 30700591; PMCID: PMC6404470.