Association between physical fitness components and fluid intelligence according to body mass index in schoolchildren.

Physical fitness is considered a protective factor for children's general health and has been related to enhanced cognitive functioning. However, it appears that cognition could be affected in children with overweight or obesity. The present study aimed to determine the relationship between physical fitness components and fluid intelligence in normal-weight and overweight/obese children. In this cross-sectional study, a total of 317 schoolchildren participated (165 boys, 52.05%), aged between six and 11 years old (1st to 5th grade), belonging to a public school in the south of Brazil. Psychologists evaluated fluid intelligence through the Raven's Colored Progressive Matrix Test. The physical fitness evaluation followed the procedures of the "Brazil Sports Project". Weight and height were measured to determine body mass index and generalized linear regression analyses were used with a 95% confidence interval. Our results showed that agility was inversely associated with fluid intelligence only in the overweight/obese group (β = -1.506; p = 0.01). Cardiorespiratory and muscular fitness were not associated with fluid intelligence. In conclusion, agility was the only physical fitness component related to fluid intelligence, and this relationship was found exclusively in overweight/obese schoolchildren.