Physical Exercise and Brain Health

Healthy Seniors

What is the con­nec­tion between phys­i­cal and men­tal exer­cise? Do they have addi­tive effects on brain health? Are they redundant?

Let’s start by review­ing what we know about the effects of phys­i­cal exer­cise on the brain.

The effect of phys­i­cal exer­cise on cog­ni­tive performance

Ear­ly stud­ies com­pared groups of peo­ple who exer­cised to groups of peo­ple who did not exer­cise much. Results showed that peo­ple who exer­cised usu­al­ly had bet­ter per­for­mance in a range of cog­ni­tive tasks com­pared to non-exercisers.

Lau­rin and col­leagues (2001) even sug­gest­ed that mod­er­ate and high lev­els of phys­i­cal activ­i­ty were asso­ci­at­ed with low­er risk for Alzheimer’s dis­ease and oth­er dementias.

The prob­lem with these stud­ies is that the exer­cis­ers and the non-exer­cis­ers may dif­fer on oth­er fac­tors than just exer­cise. The advan­tage that exer­cis­er show may not come from exer­cis­ing but from oth­er fac­tors such as more resources, bet­ter brain health to start with, bet­ter diet, etc.

The solu­tion to this prob­lem is to ran­dom­ly assigned peo­ple to either an aer­o­bic train­ing group or a con­trol group. If the exer­cis­er group and the non-exer­cis­er group are very sim­i­lar to start with and if the exer­cis­er group shows less decline or bet­ter per­for­mance over time than the non-exer­cis­er group, then one can con­clude that phys­i­cal exer­cise is ben­e­fi­cial for brain health.

In 2003, Col­combe and Kramer, ana­lyzed the results of 18 sci­en­tif­ic stud­ies pub­lished between 2000 and 2001 that were con­duct­ed in the way described above.

The results of this meta-analy­sis clear­ly showed that fit­ness train­ing increas­es cog­ni­tive per­for­mance in healthy adults between the ages of 55 and 80.

Anoth­er meta-analy­sis pub­lished in 2004 by Heyn and col­leagues shows sim­i­lar ben­e­fi­cial effects of fit­ness train­ing on peo­ple over 65 years old who had cog­ni­tive impair­ment or dementia.

What is the effect of fit­ness train­ing on the brain itself?

Research with ani­mals has shown that in mice, increased aer­o­bic fit­ness (run­ning) can increase the num­ber of new cells formed in the hip­pocam­pus (the hip­pocam­pus is cru­cial for learn­ing and mem­o­ry). Increased exer­cise also has a ben­e­fi­cial effect on mice’s vas­cu­lar system.

Only one study has used brain imag­ing to look at the effect of fit­ness on the human brain. In 2006, Col­combe and col­leagues ran­dom­ly assigned 59 old­er adults to either a car­dio­vas­cu­lar exer­cise group, or a non­aer­o­bic exer­cise con­trol group (stretch­ing and ton­ing exer­cise). Par­tic­i­pants exer­cised 3h per week for 6 months. Col­combe et al. scanned the par­tic­i­pants’ brains before and after the train­ing period.

After 6 months, the brain vol­ume of the aer­o­bic exer­cis­ing group increased in sev­er­al areas com­pared to the oth­er group. Vol­ume increase occurred prin­ci­pal­ly in frontal and tem­po­ral areas of the brain involved in exec­u­tive con­trol and mem­o­ry process­es. The authors do not know what under­ly­ing cel­lu­lar changes might have caused these vol­ume changes. How­ev­er they sus­pect, based on ani­mal research, that vol­ume changes may be due to an increased num­ber of blood ves­sels and an increased num­ber of con­nec­tions between neurons.

How does phys­i­cal exer­cise com­pare to men­tal exercise?

Very few stud­ies have tried to com­pare the effect of phys­i­cal exer­cise and men­tal exer­cise on cog­ni­tive performance.brain books

When look­ing at each domain of research one notices the fol­low­ing differences:

- The effects of cog­ni­tive or men­tal exer­cise on per­for­mance seem to be very task spe­cif­ic, that is trained tasks ben­e­fit from train­ing but the ben­e­fits do not trans­fer very well to tasks in which one was not trained.

- The effects of phys­i­cal exer­cise on per­for­mance seem broad­er. How­ev­er they do not gen­er­al­ize to all tasks. They ben­e­fit most­ly tasks that involve exec­u­tive-con­trol com­po­nents (that is, tasks that require plan­ning, work­ing mem­o­ry, mul­ti­task­ing, resis­tance to distraction).

To my knowl­edge only one study tried to direct­ly com­pare cog­ni­tive and fit­ness training:

Keep read­ing…

9 Comments

  1. ozee on June 28, 2008 at 10:28

    Hel­lo.

    By doing a lit­tle read­ing on your great web­site I under­stand there is a great empha­sis on how to keep the brain sharp and I am must admit many great tips. How­ev­er in my opin­ion phys­i­cal exer­cise appears to give more val­ue to bet­ter brain health in gen­er­al than doing men­tal exer­cis­es. This is because when doing men­tal exer­cise it is vir­tu­al­ly min­i­mal to see a pos­i­tive trans­fer affect oth­er than the task you train­ing in.

    With phys­i­cal exer­cise there is gen­er­al trans­fer effect and until proved oth­er­wise there should be more empha­sis on phys­i­cal exer­cise than men­tal stimulation.



  2. Alvaro on June 30, 2008 at 2:09

    Hel­lo Ozee,

    Thanks for the com­ment. Giv­en the exist­ing evi­dence, we have decid­ed in favor of a mul­ti-pronged approach, that high­lights the ben­e­fits of phys­i­cal exer­cise, men­tal stim­u­la­tion, stress man­age­ment and good nutrition.

    This approach is con­sis­tent with excel­lent recent pub­lic health efforts led by the Alzheimer’s Asso­ci­a­tion and the Dana Foun­da­tion For Brain Ini­tia­tives, both of which are ground­ed on four close-to-iden­ti­cal pil­lars or factors.

    Why a mul­ti-pronged approach vs. a “one size fits all”?

    Because dif­fer­ent bod­ies of research sug­gest the ben­e­fits of dif­fer­ent approach­es, and there is few research con­trast­ing their inter­ac­tions direct­ly (as Dr. Mich­e­lon points above).

    For exam­ple, advo­cat­ing that “there should be more empha­sis on phys­i­cal exer­cise than men­tal stim­u­la­tion” would ignore a large body of Cog­ni­tive Reserve research on the ben­e­fits of life­long edu­ca­tion and men­tal stim­u­la­tion to reduce the prob­a­bil­i­ty of devel­op­ing Alzheimer’s symp­toms, very sol­id large-scale clin­i­cal tri­als such as ACTIVE, and many con­trolled tri­als that show the ben­e­fits of well-direct­ed men­tal exer­cise like med­i­ta­tion, cog­ni­tive ther­a­py, com­put­er­ized cog­ni­tive train­ing, for spe­cif­ic pop­u­la­tions and goals.

    Anoth­er exam­ple on why a “one size fits all” is not the best approach: the ben­e­fits of phys­i­cal exer­cise are most­ly based on mov­ing peo­ple from Seden­tary to Slight­ly Active. Now, there are many peo­ple who are not Seden­tary, who may ben­e­fit from oth­er approaches.

    So, I would turn the tables, and say that, right now, most brain health pub­lic edu­ca­tion efforts are based on a mul­ti-pronged approach and if any­one wants to focus exclu­sive­ly on one fac­tor for every­one and every­thing will have to prove a more sol­id case than the one avail­abe on exist­ing data today.



  3. Glnn on June 30, 2008 at 3:04

    Men­tal exer­cis­es that would have a pos­i­tive trans­fer effect to oth­er men­tal tasks
    are exer­cis­es in atten­tion and concentration.
    Med­i­ta­tion is the sim­plest exam­ple of this.



  4. Scott Hagwood on July 5, 2008 at 10:25

    Does phys­i­cal exer­cise, in humans, con­tribute to neu­ro­ge­n­e­sis? If so, would cog­ni­tive exer­cise then nur­ture the new cells cre­at­ing brain volume?



  5. Alvaro on July 7, 2008 at 10:23

    Scott, very well put, that seems to be the case.

    Now, it is per­haps not “vol­ume” that grows (our skulls lim­it over­all vol­ume) but den­si­ty and weight, over­all and in spe­cif­ic brain struc­tures. Pret­ty amaz­ing, isn’t it?



  6. Encefalus on August 8, 2008 at 2:56

    Very well writ­ten! I’ll keep these in mind.



  7. Shane on October 23, 2008 at 10:36

    Per­fect expla­na­tion and good to read and get­ting good tips like this will help me in my rou­tine of exercises..It will be more effec­tive with the help of Aer­o­bic dance too..



  8. Glenn on December 5, 2008 at 3:37

    As a Phys­i­cal Edu­ca­tor, it’s great to have this infor­ma­tion avail­able. Do you have any research sim­i­lar to Col­combe and Kramer that sup­ports sim­i­lar find­ings in chil­dren and youth?

    Please keep up the great work.



  9. Joe Herzog on October 14, 2009 at 8:14

    The research gath­ered by Dr. Ratey (Spark, A User’s Guide to The Brain, Dr. John Med­i­na (Brain Rules) and Dr. Car­la Han­naford (Smart Moves) among oth­ers gives phys­i­cal edu­ca­tors a wealth of evi­dence to present to school admin­is­tra­tions about the val­ue of qual­i­ty phys­i­cal edu­ca­tion. It should also moti­vate the entire phys­i­cal edu­ca­tion com­mu­ni­ty to take a hard look at cur­rent cur­ricu­lum and the need to make changes that brings it more in line with stu­dents long term needs, social, emo­tion­al, phys­i­cal and cognitive.



About SharpBrains

SHARPBRAINS is an independent think-tank and consulting firm providing services at the frontier of applied neuroscience, health, leadership and innovation.
SHARPBRAINS es un think-tank y consultoría independiente proporcionando servicios para la neurociencia aplicada, salud, liderazgo e innovación.

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