Impact of Pain and Physical Inactivity on Cognitive Function

Connection Between Cognitive Decline and Dementia

Pain and physical inactivity are linked to an increased risk of cognitive decline, potentially leading to dementias such as Alzheimer’s disease. A recent study explored the relationship between pain levels, physical activity, and cognitive function.

Prevalence of Dementia Among Older Adults

Nearly 25% of Americans aged 85 and older are affected by dementias, including Alzheimer’s disease. These conditions significantly diminish quality of life and place considerable strain on families and caregivers. Gaining insights into the lifestyle and health factors contributing to dementia could aid researchers in developing strategies to mitigate the progression of these diseases.

Research Insights on Pain, Activity, and Cognitive Function

Previous studies have indicated that both pain and physical inactivity can result in slight reductions in cognitive function, which may contribute to the onset of dementia. While many studies have examined pain and physical activity independently, a group of Italian researchers aimed to investigate both factors concurrently to determine their combined effect on cognitive function. Their findings were published in PLOS ONE.

Study Methodology and Findings

Data Source: National Health and Nutrition Examination Survey

The researchers utilized data from the National Health and Nutrition Examination Survey (NHANES), which included thousands of older adults in the U.S. The average age of participants was 72, with a balanced gender distribution. Cognitive function assessments were conducted on nearly 3,000 older adults between 1999 and 2002.

Cognitive Function Assessment

Participants were given a task involving a table of numbers (1-9) paired with different abstract symbols (e.g., ┴ or Λ). They were required to match the symbols to the numbers as quickly as possible. The researchers then correlated the results of this cognitive task with the participants’ reported physical activity levels and experiences of pain in their daily lives.

Socioeconomic Status and Cognitive Function

The study began by comparing cognitive function scores, dividing participants into upper and lower halves. Women, younger individuals, married persons, and American citizens were more likely to score in the upper half of socioeconomic status. Additionally, higher household incomes and educational attainment were associated with better cognitive function.

Types of Pain and Their Impact

Participants reported various pain types, including joint, back, and neck pain. Most pain types did not show significant differences in cognitive function; however, left shoulder pain was an exception, correlating with lower cognitive function scores.

Physical Activity and Cognitive Function Correlation

Participants who engaged in high levels of physical activity were more likely to achieve higher cognitive function scores. Various forms of physical activity, including household tasks, vigorous and moderate exercises, and muscle-strengthening activities, were positively associated with cognitive function. Notably, active individuals with pain did not exhibit different cognitive scores compared to their less painful counterparts, indicating that physical activity played a more significant role than pain in cognitive performance.

Conclusions and Future Directions

Physical Activity as a Key Predictor

While the study had limitations, including its observational nature and reliance on a single cognitive function test, it highlighted the strong link between physical activity and cognitive function among older American adults. The association between pain and cognitive function appeared much weaker, suggesting that physical activity may outweigh the impact of pain on cognitive health.

Implications for Future Research

These findings do not diminish the importance of addressing pain; however, they suggest that future research should prioritize physical activity as a potential intervention for reducing age-related cognitive decline.

References

(1) Maldonato, N. M., et al. “Keep moving without hurting: The interaction between physical activity and pain in determining cognitive function at the population level.” PLOS ONE 13, e0197745 (2018). https://doi.org/10.1371/journal.pone.0197745
(2) Koller, D. & Bynum, J. P. W. “Dementia in the USA: state variation in prevalence.” Journal of Public Health 37, 597-604 (2015). https://doi.org/10.1093/pubmed/fdu080