The effect of social network on the physical activity - Cognitive function nexus in late life

Background: To examine the contribution of vigorous physical activity to subsequent cognitive functioning, taking into account the effect of social network.Methods: The sample included respondents aged 65 years and older who participated in both the fourth and sixth waves of Survey of Health, Ageing and Retirement in Europe (n = 17,104). Cognitive functioning in Wave 6, measured as the average of standardized scores for recall, fluency, and numeracy, was regressed on the extent of vigorous physical activity, social network size, and several confounders in Wave 4 (including the corresponding cognition score at baseline). Interaction terms for physical activity and network size were also considered.Results: Moderate and high levels of vigorous physical activity, as well as social network size, were related to the cognition outcome after controlling for the confounders. Introduction of the interaction terms showed a direct and positive association of both moderate and high physical activity with the cognition outcome scores as social network size increased. However, among respondents in small- (0-1 members) and moderate-sized networks (2-3 members), greater physical activity was unrelated to the cognition score at follow-up. Only the interaction of high social connectedness (4-7 network members) and vigorous physical activity was significant.Conclusions: Vigorous physical activity is, indeed, related to subsequent cognitive functioning. However, the relationship is tempered by social network size. Therefore, interventions that increase both social connectedness and physical activity, especially among older people who are isolated and sedentary, are warranted.