Television viewing time and measured cardiorespiratory fitness in adult women

Purpose: This study assessed the relationship between television viewing time and measured cardiorespiratory fitness and the influence of various potential confounders.

Design: Cross-sectional.

Setting: Intermountain West.

Subjects: The sample was composed of 302 nonsmoking women aged 40.2 ± 3.0 years, with ~90% Caucasian and 82% married.

Measures: TV viewing was assessed by using a questionnaire, and cardiorespiratory fitness was measured by using a graded, maximum treadmill test. Physical activity (PA) was evaluated by using accelerometers for 7 days, and body fat percentage (BF%) was measured by using the Bod Pod.

Analysis: Analysis of variance and partial correlation.

Results: VO2max of Frequent (≥3 h/d) TV viewers (32.6 ± 6.4 mL/kg/min) was significantly lower than that of both Moderate (1-2 h/d) (36.2 ± 7.2 mL/kg/min) or Infrequent (<1 h/d) (36.5 ± 6.5 mL/kg/min) viewers (F = 8.0, p = .0004). The Infrequent and Moderate groups did not differ in VO2max. Age, education, body mass index, and season of assessment had no influence on the relationship when controlled statistically. Adjusting for PA (F = 4.2, p = .0157) and BF% (F = 5.0, p = .0071) weakened the relationship by 59% and 58%, respectively, but the relationships remained significant. After controlling for both PA and BF% simultaneously (F = 2.9, p = .0572), the relationship was weakened by 81% and was only borderline significant.

Conclusion: Female Frequent TV viewers have significantly lower cardiorespiratory fitness levels than Moderate or Infrequent viewers. This association appears to be largely a function of differences in levels of PA and BF%.