Purpose: Higher levels of sedentary behaviour are associated with lower cognitive function, however the association with executive function needs to be further elucidated. We aimed to identify any associations of sedentary behaviour with executive function in mid age and older adults, overall and by SB domain.  

Methods: EMBASE, Web of Science, PsycINFO, CINAHL, SciELO, SPORTDiscus, PubMed and Scopus were systematically searched using medical subject headings and key words. Studies were screened by two researchers and included if they reported sedentary behaviour time, had participants with a mean age 40 years or older, had executive function as an outcome and were published in English. Data on specific study characteristics were extracted and studies were assessed for quality using a standardised measure. 

Results:Fourteen studies (n=22,072) met the inclusion criteria, nine of which measured sedentary behaviour with a device and only one of those assessing posture. Five studies were longitudinal, eight cross-sectional and one was a randomised two-condition crossover trial. Mean quality score was 20/24 (83%). Participants on average were 56% female with a mean age of 64 years. Executive function was measured with twelve different tests, the most common being the Trail Making Test (k=4). With respect to relations between overall sedentary behaviour and executive function, two longitudinal and four cross-sectional studies reported detrimental associations, one study reported both beneficial and no association, and four studies reported no association. Three studies (two longitudinal, one cross-sectional) examined television (TV) time as a specific domain; all three found an association of increasing TV time with poorer executive function. 

Conclusions: There is more consistent evidence for higher domain-specific sedentary behaviour, i.e. TV time than higher overall sedentary behaviour being associated with poorer executive function. Future studies should include a more valid measure of sedentary behaviour and include a longer follow up period. More studies are needed to determine whether other sedentary behaviour domains are related to executive function. From an intervention perspective, investigating how reducing sedentary behaviour, specifically TV time can impact executive functioning in mid age and older adults is recommended. 

Purpose: Sedentary behaviour might be a potential risk factor for cognitive decline. However, the short-term effects of sedentary behaviour on (cerebro)vascular and cognitive performance in older people are unknown.

Methods: We used a cross-over design with 22 older adults (78 years, 9 females) to assess the short-term hemodynamic and cognitive effects of three hours uninterrupted sitting and explored if these effects can be influenced with regular (every 30 minutes) two-minute walking breaks. In addition, we investigated if low versus high mental activity during the 3 hours of sitting modified these effects. Before and after each condition, cerebral blood flow velocity (CBFV; Transcranial Doppler) and blood pressure (Finapres) were measured in rest and during sit-to-stand and CO₂ challenges to assess baroreflex sensitivity, cerebral autoregulation (CA), and cerebral vasomotor reactivity (CVMR). Alertness, executive functioning, and working memory were assessed with the Test of Attentional Performance battery. A mixed model analysis was performed with separate terms for time, and the interaction between time and sit/break and mental activity respectively.

Results: Blood pressure and cerebrovascular resistance increased over time (8.6 mmHg (5.0;12.1), p<0.001), and 0.23 in resistance (0.01;0.45), p=0.04). However, these effects were not mitigated by mental activity or by short walking breaks to interrupt sitting. No short-term differences were observed in CBFV, baroreflex sensitivity, CA, CVMR, or cognitive performance across time, or between conditions.

Conclusions: In older individuals, three hours of sitting increased blood pressure and cerebrovascular resistance, which are known to negatively impact brain health in the long-term. Importantly, we found that these effects in older individuals cannot be mitigated by higher mental activity and/or regular walking breaks. Therefore these findings have important implications for the current ideas about preventing the negative effects of sedentary behaviour in older adults.

Purpose: This study aimed to evaluate the impact on cognitive function of an intervention targeting reducing and interrupting prolonged sitting compared with usual practice.

Methods: 42 inactive pre-frail/frail older people were recruited from a seniors centre and randomized to intervention or usual care. The 12-week REduce Sitting to improve Cognitive fUnction in Elders (RESCUE) program was delivered by a health coach in one face-to-face and five telephone sessions. The intervention group completed a workbook during the sessions with the health coach and received printed feedback on device-measured sitting at their initial session. Primary outcome was cognitive function (California Verbal Learning Test and Trail Making Test) with secondary outcomes of sitting, standing, stepping (activPAL). Analysis was by linear mixed models.

Results: At baseline, participants (88% women; mean±SD age = 80±7 years; MMSE = 29.1±1.0) sat for 607±135 minutes, stood for 258±104 minutes, and stepped for 68±28 minutes of their waking hours. Nineteen participants completed each condition. There was no intervention effect for the California Verbal Learning Test -0.3 (95%CI: -1.7, 1.0) words. Intervention effects, favouring intervention group, were observed for Trail Making A test  -7.3 (-13.7, -1.0; baseline = 43.4±17.7) seconds; Trail Making B test  -20.2 (-37.9, -2.5; baseline = 131.3±57.5) seconds;  daily sitting accrued in bouts longer than 30 minutes -57.8 (-111.3, -4.2) minutes/day, standing 36.7 (7.3, 65.7) minutes/day; and, stepping 8.5 (2.8, 14.3) minutes/day.

Conclusions: RESCUE successfully reduced prolonged sitting time and positive changes were observed for visual attention and task switching but not verbal learning and memory. While these findings provide preliminary evidence that reducing prolonged sitting results in improvements in some domains of cognitive function, more research is needed to evaluate the impact on other domains of cognitive function, and over a longer period, and whether changes in sitting time and cognitive function are maintained.