Currently, half of adults spend more than 9.5 hours of their day sitting, and sedentary behaviours have been associated with both cognitive and structural brain aging. Sedentary behaviour is defined as “any waking behaviour characterised by an energy expenditure ≤1.5 METs (metabolic equivalent units) while in a sitting or reclining posture. Studies in the past has shown a link between sedentary behaviour and the risk of developing dementia. The risk was dependent on the activity performed while sedentary (passively watching TV vs active computer use). However, a follow-up study was not able to substantiate the link between sedentary behaviour and incident of dementia in older female participants (n=1,277) despite using the accelerometer to measure their sitting time. However, to understand the relationship between sedentary behaviour and dementia further, Raichlen et al., (2023) evaluated the link between sedentary behaviours with the incidence of dementia by measuring the time spend sedentary using a wearable accelerometry data in older adults. A total of 49,841 older adults with a mean age of 67.19 years and mean follow-up of 6.72 years. The study concluded that older adults who spend prolong periods sitting were at higher risk of all-cause dementia. Contrary to this, the time spend physically active has shown to lower the risk of dementia, however, the beneficial effect of physical activity is lost in those who work out but then remain seated for a prolonged period (≥10 hours). Even though this study was more of an associational study, it highlighted the risk of sedentary lifestyle and the disease process in older adults. Therefore, sitting for prolonged periods may cause more harm than good to the body.

References:

Raichlen DA, et al. JAMA 2023;330(10):934-40. 

Tremblay MS, et al. Int J Behav Nutr Phys Act 2017;14(1):75. 

Raichlen DA, et al. Proc Natl Acad Sci USA 2022;119(35):e2206931119. 

Nguyen S, et al. Alzheimers Dement 2023;19(7):3041-54. 

Del Pozo Cruz B, et al. JAMA Neurol 2022;79(10):1059-63