Lifestyle matters: What we can do in 2024 to optimize cognition and life, delaying cognitive problems even dementia

Walk 10,000 steps a day, cut back alco­hol, get bet­ter sleep at night, stay social­ly active — we’re told that changes like these can pre­vent up to 40 per cent of demen­tia cas­es worldwide.

Giv­en that demen­tia is still one of the most feared dis­eases, why aren’t we push­ing our doc­tors and gov­ern­ments to sup­port these lifestyle changes through new pro­grams and pol­i­cy initiatives?

The truth, how­ev­er, is more com­plex. We know that mak­ing lifestyle changes is hard. Ask any­one who has tried to keep their New Year’s res­o­lu­tion to vis­it the gym three times a week. It can be dou­bly dif­fi­cult when the changes we need to make now won’t show results for years, or even decades, and we don’t real­ly under­stand why they work.

Taking control of your health:

Any­one who has watched a loved one liv­ing with demen­tia, fac­ing the small and large indig­ni­ties and declines that leave them even­tu­al­ly unable to eat, com­mu­ni­cate or remem­ber, knows it is a dev­as­tat­ing disease.

There are sev­er­al new drugs mak­ing their way to the mar­ket for Alzheimer’s dis­ease (one of the most com­mon forms of demen­tia). How­ev­er, they are still far from a cure and are cur­rent­ly only effec­tive for ear­ly-stage Alzheimer’s patients.

So lifestyle changes may be our best hope of delay­ing demen­tia or not devel­op­ing demen­tia at all. Actor Chris Hemsworth knows it. He watched his grand­fa­ther live with Alzheimer’s and is mak­ing lifestyle changes after learn­ing he has two copies of the APOE4 gene. This gene is a risk fac­tor for Alzheimer’s, and hav­ing two copies sig­nif­i­cant­ly increas­es his risk of devel­op­ing the same condition.

Research has iden­ti­fied mod­i­fi­able risk fac­tors that con­tribute to increas­ing the risk of dementia:

• phys­i­cal inactivity
• exces­sive use of alcohol
• less sleep
• social iso­la­tion
• hear­ing loss
• less cog­ni­tive engagement
• poor diet
• hyper­ten­sion
• obe­si­ty
• dia­betes
• trau­mat­ic brain injury
• smok­ing
• depres­sion
• air pol­lu­tion

Our under­stand­ing of the bio­log­i­cal mech­a­nisms for these risk fac­tors is var­ied, with some more clear­ly under­stood than others.

But there is a lot we do know — and here’s what you need to know as well.

Cognitive reserve and neuroplasticity:

Cog­ni­tive reserve is the brain’s abil­i­ty to with­stand dam­age or neu­rode­gen­er­a­tive dis­ease. If there is tis­sue or func­tion­al loss in one part of the brain, oth­er brain cells (neu­rons) work hard­er to com­pen­sate. In the­o­ry, this means life­long expe­ri­ences and activ­i­ties cre­ate a dam against the dam­ages of dis­ease and aging in the brain.

Neu­ro­plas­tic­i­ty is the brain’s amaz­ing abil­i­ty to adapt, learn and reor­ga­nize, cre­ate new path­ways or rewire exist­ing ones to recov­er from dam­age. The key take­away is that neu­ro­plas­tic­i­ty can hap­pen at any time and any age, which means learn­ing and activ­i­ties should be lifelong.

Many of the risk fac­tors linked to demen­tia like­ly work in com­bi­na­tion, which is why an over­all lifestyle approach is cru­cial. For exam­ple, stud­ies have shown that exer­cise, cog­ni­tive and social engage­ment stim­u­late your brain and main­tain its plas­tic­i­ty by grow­ing new neur­al con­nec­tions and build­ing cog­ni­tive reserve.

The mech­a­nism behind this is a com­bi­na­tion of fac­tors: increased oxy­gen and blood flow to the brain, stim­u­lat­ing growth fac­tors that keep neu­rons healthy and reduced inflammation.

The oppo­site is also true. Poor sleep, diet, social iso­la­tion and untreat­ed depres­sion are linked to decreased cog­ni­tive reserve.

The same ratio­nale applies to hear­ing loss, a key emerg­ing risk fac­tor for demen­tia. As a person‘s hear­ing decreas­es, it can make it dif­fi­cult to social­ly engage with oth­ers, result­ing in a loss of sen­so­ry input. The brain has to work hard­er to com­pen­sate for this, poten­tial­ly draw­ing down its cog­ni­tive reserve and leav­ing it less able to with­stand dementia.

The role of stress and inflammation:

Stress respons­es and inflam­ma­tion are the body’s com­plex answer to injury. Inflam­ma­tion is an impor­tant com­po­nent of the body’s immune sys­tem, help­ing defend against threats and repair tis­sue dam­age. While short-term inflam­ma­tion is a nat­ur­al and good response, chron­ic or pro­longed inflam­ma­tion dis­rupts nor­mal func­tion and caus­es dam­age to the brain’s cells.

For exam­ple, one of the com­mon­al­i­ties between demen­tia and untreat­ed depres­sion is the inflam­ma­to­ry process. Pro­longed expo­sure to stress hor­mones can lead to chron­ic inflam­ma­tion. Hyper­ten­sion, phys­i­cal inac­tiv­i­ty, smok­ing and air pol­lu­tion are also asso­ci­at­ed with chron­ic inflam­ma­tion and stress, which can dam­age blood ves­sels and neu­rons in the brain.

In a new­er area of research still being explored, social iso­la­tion has also been linked to inflam­ma­tion. As we learned dur­ing the COVID-19 pan­dem­ic, the brain is wired to respond to social engage­ment as a means of bond­ing and emo­tion­al sup­port, espe­cial­ly in times of distress.

With sur­veys show­ing more than one in three Cana­di­ans feel iso­lat­ed, the lack of social con­nec­tion and lone­li­ness can trig­ger the body’s stress response and neu­roen­docrine changes, and pro­longed expo­sure to this inflam­ma­to­ry process can dam­age the brain.

Similar pathways across multiple diseases:

Sev­er­al of these risk fac­tors, and their bio­log­i­cal path­ways, cut across mul­ti­ple chron­ic dis­eases. Accu­mu­lat­ing evi­dence of decades of research sup­ports the con­cept of “what’s good for your heart is good for your head.”

This means that mak­ing these lifestyle changes not only reduces your risk of demen­tia, but also your risk of dia­betes, hyper­ten­sion and heart con­cerns. This high­lights the com­plex nature of demen­tia but also offers a unit­ed strat­e­gy to deal with mul­ti­ple health con­cerns that may arise as peo­ple age.

It’s nev­er real­ly too late to change. The human brain and body have a remark­able capac­i­ty for adap­ta­tion and resilience through­out life.

While there are ben­e­fits to being phys­i­cal­ly and social­ly active at any age, some research shows the pay­off from those gains can be high­er after age 40 when the body’s metab­o­lism slows, risk fac­tors increase and cog­ni­tive reserve becomes even more essen­tial to help pro­tect against cog­ni­tive decline.

If mak­ing lifestyle changes means you can watch your child nav­i­gate adult­hood, stroll 20 blocks to your favourite café every day and con­tin­ue to live in your own home, per­haps walk­ing the dai­ly 10,000 steps, chang­ing diets and keep­ing your friend­ship net­work strong is worth­while. At worst, you’ll be health­i­er and more inde­pen­dent with or with­out demen­tia. At best, you might com­plete­ly avoid demen­tia and oth­er major dis­eases and keep liv­ing your best pos­si­ble life.

Sask­ia Sivanan­than is an Affil­i­ate Pro­fes­sor in the Depart­ment of Fam­i­ly Med­i­cine at McGill Uni­ver­si­ty, and for­mer Chief Research & KTE Offi­cer at the Alzheimer Soci­ety of Cana­da. Lau­ra Mid­dle­ton is an Assis­tant Pro­fes­sor in the Depart­ment of Kine­si­ol­o­gy at Uni­ver­si­ty of Water­loo, research­ing ways to opti­mize cog­ni­tion across the life course and to pre­vent demen­tia in late life. This arti­cle was orig­i­nal­ly pub­lished on The Con­ver­sa­tion.

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