The effects of sedentary behavior on memory and markers of memory function: a systematic review

Objective: To evaluate the association of sedentary behavior on memory and markers of memory among humans of all ages.Methods: PubMed, PsychInfo, Sports Discus and Google Scholar databases were searched. Inclusionary criteria included: Published in English; conducted among humans (children to older adults); employ a cross-sectional, prospective or experimental design; include a measure of sedentary behavior as the independent variable (e.g. time spent sitting or watching television); and include a memory-related outcome measure (e.g. behavioral performance on a memory task, brain tissue volume in a memory structure). Information on participant characteristics, study design, sedentary behavior measure, memory outcome measure, and hypothesized mechanisms were extracted. The relationship between sedentary behavior and memory was synthesized while considering the data extraction parameters.Results: In total, 25 articles met the inclusionary criteria, including 8 studies among children/adolescents and 17 among adults. Sedentary behavior was assessed subjectively (e.g. TV viewing, computer use, reading) and objectively (e.g. accelerometry). Outcome measures included behavioral performance on various memory tasks (e.g. episodic and working memory), BDNF levels, brain volumetric measures of the temporal lobe, and hippocampal glucose metabolism. Overall, for both the child and adult studies, findings were mixed, with studies demonstrating null, inverse, and positive associations between sedentary behavior and memory. Sedentary behavior type may play a distinct role in the relationship between sedentary behavior and memory, as computer use, in particular, appeared to favorably influence memory when compared to other sedentary types (e.g. TV viewing, which showed in inverse association with memory in select studies).Conclusion: There is conflicting evidence of the relationship between sedentary behavior and memory-related outcomes among children and adults. Future studies are needed to further disentangle these complex interrelationships. Such studies should also carefully consider how physical activity may or may not moderate these relationships.