Next, I direct you to Webber and coworkers' investigation of recovery after knee arthroplasty. Despite reductions in pain, levels of moderate-to-vigorous physical activity (MVPA) do not change substantially after total knee replacement. What about sedentary behavior and light activity—do people find it easier to sit less and engage in more activity (even if not MVPA)? Discouragingly, they found no differences in daily sedentary time, number of long sedentary bouts, or minutes of light activity between people waiting for knee replacement and those one-year post surgery. Continued high levels of sedentary behavior put these individuals at increased risk for physical decline and cardiovascular disease. Additional education and rehabilitation (including behavior change strategies) are needed.
Finally, Wijndaele et al. estimated the potential mortality risk benefits of replacing leisure-screen-time (including TV viewing) with different discretionary activities in almost 0.5 million middle-age adults without major chronic disease, followed for almost 8 years. Their findings suggested that replacing small amounts of leisure-screen-time (e.g., 30 min·d−1) with everyday activities such as do-it-yourself home maintenance and improvement, and gardening could result in relevant mortality benefits. These may be important targets for adults for whom taking up exercise and strenuous sports (which show stronger mortality benefits) to replace screen-time seems less feasible. Assuming causality, they also estimated that 4%–15% of premature deaths in the UK could be avoided through such substitutions, depending on activity intensity. Given the ubiquitous nature of leisure-screen-time and the achievability of the proposed behavioral change scenarios, these findings are of great public health importance.
L. Bruce Gladden
School of Kinesiology