Television Viewing and Body Fat in 281 Women: The Role of Physical Activity

Purpose The aim of this investigation was to evaluate the association between television viewing (TV) and body fat percentage in 281 middle-aged women. An additional goal was to ascertain the extent to which physical activity and energy intake explain differences in adiposity among women with various TV viewing habits.

Methods The typical number of hours spent watching TV and videos each day was self-reported Three categories were formed based on hours of self-reported TV viewing: Infrequent Viewers, ≤2 hrs TV per day; Moderate Viewers, 3 hrs per day; and frequent Viewers, ≥4 hrs per day. Body fat percentage (BF%) was measured using the Bod Pod. Subjects were tested until two Sod Pod results were within 1 percentage point of each other, then the average of the two measures was used to index BF%. Physical activity was measured using CSA accelerometers worn over the left hip for 7 consecutive days. Energy intake was assessed using 7-day, weighed food records, kept during the same 7 days that activity was measured.

Results Average age of the sample was 40 years, and participants were primarily Caucasian (95%), educated (36% had a college degree), and married (80%). Among the 281 women, 215 (76%) reported infrequent TV viewing, 38 (14%) reported moderate viewing, and 28 (10%) reported frequent viewing. Mean BF%, physical activity counts, and energy intake were 31.7 ± 6.9, 2.7 ± 0.8 million counts, and 2054 ± 315 heal, respectively. BF% differed significantly among the TV groups (F = 4.2, p = 0.0167). Specifically, Infrequent Viewers had the lowest BF% 31.1 ± 6.9, followed by Moderate Viewers 32.5 ± 7.0, and then Frequent Viewers, 35.0 ± 6.5. Adjusting for difference in physical activity weakened the relationship by 30%, but the association between TV and BF% remained significant. Controlling for energy intake had little effect on the association, weakening it by 13%.

Conclusion Apparently, the relationship between TV viewing and body fat is partly due to differences in physical activity levels; however, other unmeasured factors seem to play important roles in the association.