Physically active individuals are suggested to have enhanced  cognitive performance through life course, but the role of sedentary behavior for cognitive function is unknown.

PURPOSE: To evaluate the cross-sectional associations of TV viewing time (as an indicator of sedentary behavior) with cognitive performance in midlife.

METHODS: 1889 eligible subjects (1033 women, 856 men; aged 34-49 y) were drawn from the 31-year follow-up of the population-based Cardiovascular Risk in Young Finns study in 2011. A computerized testing battery (CANTAB®) was used to assess cognitive performance. The test included Paired associates learning test (PAL), Spatial working memory test (SWM), Reaction time test (RTI), and Rapid visual information test (RVP). Principal component analyses were used to define components indicating function on several cognitive domains. Data on daily TV viewing time, physical activity, and education were derived from self-administered questionnaires.

The associations were studied with linear, or Poisson, regression analyses. Adjustments were made for age, sex, education and physical activity.

RESULTS: High TV viewing time was associated with more total errors (beta for one additional TV hour [SE]: 1.1 [0.4]) and more total trials (0.2 [0.1]) in PAL test, increased movement time (5.4 [1.6] ms) in RTI test, and less correct rejections (-0.6 [0.2]) and total hits (-0.2 [0.1]) in RVP test (p<0.05 in all) regardless of age, sex, and education. Additional adjustment for physical activity diluted the associations, but nevertheless more total errors (0.9 [0.4]) in PAL test, increased movement time (6.0 [1.7] ms) in RTI test, and less correct rejections (-0.5 [0.2]) and total hits (-0.2 [0.1]) in RVP test remained significant (p<0.05 in all).

CONCLUSIONS: On a population level, high TV viewing time may be negatively associated with cognitive performance.