Jobs with low physical stress and good working conditions linked to larger hippocampus and better memory

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CSU study links phys­i­cal stress on the job with brain and mem­o­ry decline in old­er age (press release):

A new study out of Col­orado State Uni­ver­si­ty has found that phys­i­cal stress in one’s job may be asso­ci­at­ed with faster brain aging and poor­er memory.

Aga Burzyn­s­ka, an assis­tant pro­fes­sor in the Depart­ment of Human Devel­op­ment and Fam­i­ly Stud­ies, and her research team con­nect­ed occu­pa­tion­al sur­vey respons­es with brain-imag­ing data from 99 cog­ni­tive­ly nor­mal old­er adults, age 60 to 79. They found that those who report­ed high lev­els of phys­i­cal stress in their most recent job had small­er vol­umes in the hip­pocam­pus and per­formed poor­er on mem­o­ry tasks. The hip­pocam­pus is the part of the brain that is crit­i­cal for mem­o­ry and is affect­ed in both nor­mal aging and in dementia.

“We know that stress can accel­er­ate phys­i­cal aging and is the risk fac­tor for many chron­ic ill­ness­es,” Burzyn­s­ka said. “But this is the first evi­dence that occu­pa­tion­al stress can accel­er­ate brain and cog­ni­tive aging…“Most inter­ven­tions for post­pon­ing cog­ni­tive decline focus on leisure, not on your job. It’s kind of unknown ter­ri­to­ry, but maybe future research can help us make some tweaks to our work envi­ron­ment for long-term cog­ni­tive health.”

The Study:

Occu­pa­tion­al Phys­i­cal Stress Is Neg­a­tive­ly Asso­ci­at­ed With Hip­pocam­pal Vol­ume and Mem­o­ry in Old­er Adults (Fron­tiers in Human Neuroscience).

  • Abstract: Our jobs can pro­vide intel­lec­tu­al­ly and social­ly enriched envi­ron­ments but also be the source of major psy­cho­log­i­cal and phys­i­cal stres­sors. As the aver­age full-time work­er spends >8 h at work per week­day and remains in the work­force for about 40 years, occu­pa­tion­al expe­ri­ences must be impor­tant fac­tors in cog­ni­tive and brain aging. There­fore, we stud­ied whether occu­pa­tion­al com­plex­i­ty and stress are asso­ci­at­ed with hip­pocam­pal vol­ume and cog­ni­tive abil­i­ty in 99 cog­ni­tive­ly nor­mal old­er adults. We esti­mat­ed occu­pa­tion­al com­plex­i­ty, phys­i­cal stress, and psy­cho­log­i­cal stress using the Work Design Ques­tion­naire (Morge­son and Humphrey, 2006), Quan­ti­ta­tive Work­load Inven­to­ry and Inter­per­son­al Con­flict at Work Scale (Spec­tor and Jex, 1998). We found that phys­i­cal stress, com­pris­ing phys­i­cal demands and work con­di­tions, was asso­ci­at­ed with small­er hip­pocam­pal vol­ume and poor­er mem­o­ry per­for­mance. These asso­ci­a­tions were inde­pen­dent of age, gen­der, brain size, socioe­co­nom­ic fac­tors (edu­ca­tion, income, and job title), dura­tion of the job, employ­ment sta­tus, leisure phys­i­cal activ­i­ty and gen­er­al stress. This sug­gests that phys­i­cal demands at work and leisure phys­i­cal activ­i­ty may have large­ly inde­pen­dent and oppo­site effects on brain and cog­ni­tive health. Our find­ings high­light the impor­tance of con­sid­er­ing midlife occu­pa­tion­al expe­ri­ences, such as work phys­i­cal stress, in under­stand­ing indi­vid­ual tra­jec­to­ries of cog­ni­tive and brain aging.

Using the Work Design Ques­tion­naire, Phys­i­cal Demands were self-eval­u­at­ed with these sur­vey items:

  1. The job requires a great deal of mus­cu­lar endurance.
  2. The job requires a great deal of mus­cu­lar strength.
  3. The job requires a lot of phys­i­cal effort.

Work Con­di­tions were self-eval­u­at­ed with these sur­vey items:

  1. The work place is free from exces­sive noise.
  2. The cli­mate at the work place is com­fort­able in terms of tem­per­a­ture and humidity.
  3. The job has a low risk of accident.
  4. The job takes place in an envi­ron­ment free from health haz­ards (e.g., chem­i­cals, fumes, etc.).
  5. The job occurs in a clean environment.

The Study in Context: