The current evidence for higher physical activity and better cognitive function and lower risk of dementia is firm but not conclusive. More robust evidence is needed to inform public health policy.
A new study offers further insight into discrepancies observed across studies, reporting on habitual inactivity, including that during work.
For the study, scientists from the University of Cambridge studied cross-sectional and prospective relationships of physical inactivity during leisure and occupation time, with cognitive performance using a validated physical activity index in a cohort of 8585 men and women aged 40-79 years at baseline (1993-1997) for different domains using a range of cognitive measures.
Through a large cohort of volunteers, scientists were able to explore the relationship between different types of physical activity in a variety of settings.
As a part of the investigation, participants finished a health and lifestyle survey, including data on the level of physical activity during both work and leisure, and underwent a wellbeing assessment. Following an average of 12 years, the volunteers were welcomed back. They finished a battery of tests that deliberate aspects of their cognition, including memory, attention, visual processing speed, and a reading ability test that approximates IQ.
While numerous investigations have only been able to report cross-sectional findings, the capacity to catch up EPIC-Norfolk members over a significant stretch permitted the analysts to analyze data prospectively. This helped them preclude any bias coming about because of people with poor cognition – perhaps because of psychological debilitation or early dementia – being more averse to be genuinely dynamic because of poor cognition, instead of poor cognition being a consequence of physical inactivity.
Scientists found that:
- Individuals with no qualifications were more likely to have physically active jobs, but less likely to be physically active outside of work.
- A physically inactive job (typically a desk-job) is associated with a lower risk of poor cognition, irrespective of the level of education. Those who remained in this type of work throughout the study period were the most likely to be in the top 10% of performers.
- Those in manual work had almost three times increased risk of poor cognition than those with an inactive job.
Shabina Hayat from the Department of Public Health and Primary Care at the University of Cambridge said, “Our analysis shows that the relationship between physical activity and cognitive is not straightforward. While regular physical activity has considerable benefits for protection against many chronic diseases, other factors may influence its effect on future poor cognition.”
“People who have less active jobs – typically office-based, desk jobs – performed better at cognitive tests regardless of their education. This suggests that because desk jobs tend to be more mentally challenging than manual occupations, they may offer protection against cognitive decline.”
Journal Reference
- Hayat, SA et al. Cross-sectional and prospective relationship between occupational and leisure time inactivity and cognitive function in an aging population. The European Prospective Investigation into Cancer and Nutrition in Norfolk (EPIC-Norfolk) Study. International Journal of Epidemiology; 7 Jul 2020; DOI: 10.17863/CAM.51130