Ernesto Ramirez

Reducing Sedentary Behavior A New Paradigm in Physical Activity Promotion

There is growing interest in the role of sedentary behavior as a risk factor for poor health, independent of physical activity (PA). To guide the spectrum of descriptive, analytic, and intervention studies on sedentary behavior, the authors advocate a behavioral epidemiology framework. This 5-phase framework is useful because it outlines a series of sequential stages important for developing, evaluating, and diffusing interventions to reduce sedentary behavior and improve population health. Studies of sedentary behavior and health outcomes (phase I) have found consistent evidence that excessive use of screen-based media is linked to overweight and obesity in children, and there is some evidence among adults that overall sedentary time is associated with risk factors for cardiometabolic disease, some cancers, and mortality. Biological mechanisms to explain possible relationships have started to emerge but are mostly based on animal models. Obtaining valid and reliable measurements of sedentary behavior (phase II) remains a research priority because self-reports are prone to recall bias, and it appears that sedentary habits do not appear to be well represented by measures of individual behaviors such as TV viewing. Studies have identified few modifiable correlates of sedentary behavior (phase III), although research appears to be limited to studies of TV viewing or to scenarios in which sedentary behavior is defined as an absence of PA. Rigorous intervention research (phase IV) has focused almost exclusively on reducing self-reported TV viewing among children and adolescents, and there is consistent evidence that these interventions are efficacious. There appear to be no interventions focused exclusively on reducing sedentary behavior of adults. Translation studies (phase V) are absent because the underlying evidence is still emerging. Future research should focus on examining causal associations between sedentary behavior and health, developing objective measures of domain-specific sitting time, and identifying modifiable correlates of sedentary behavior that can be used as leverage points for behavioral interventions.

Adolescent screen time and rules to limit screen time in the home.

PURPOSE To investigate associations between adolescent screen time behaviors, screen time rules, and presence of electronic media in the bedrooms of adolescents. METHODS Parents and adolescents (N = 160 dyads) from the cities of Boston, Cincinnati, and San Diego were asked to complete a questionnaire which included questions related to demographics, screen time rules, availability of media devices, and screen time behavior. Separate multiple regression models were used for adolescent and parent reports to test correlates of adolescent television (TV) watching, video game play, and computer usage for entertainment. RESULTS Data from adolescents indicated that rules for watching TV, computer usage, and total number of screen time rules were significantly correlated with time spent watching TV (β = -.22, p < .01), playing video or computer games (β = -.18, p < .05), and using the Internet and/or computer for entertainment (β = -.18, p < .05), respectively. Data from parents indicated that TV rules were significantly associated with lower rates of TV viewing, and parent-adolescent agreement on rules strengthened this relationship. Data from parents as well as adolescents indicated that the presence of a TV in the bedroom was positively associated with TV viewing time (β = .18 and .24, p < .05, respectively). Adolescent data indicated a positive association between having at least one video game system in the bedroom and time spent playing video games (β = .19, p < .05). CONCLUSION Having clear rules, setting limits on screen time, and not having screen-based media in the bedroom were associated with fewer hours of screen time for adolescents.

A theory-based framework for evaluating exergames as persuasive technology

Exergames are video games that use exertion-based interfaces to promote physical activity, fitness, and gross motor skill development. The purpose of this paper is to describe the development of an organizing framework based on principles of learning theory to classify and rank exergames according to embedded behavior change principles. Behavioral contingencies represent a key theory-based game design principle that can be objectively measured, evaluated, and manipulated to help explain and change the frequency and duration of game play. Case examples are presented that demonstrate how to code dimensions of behavior, consequences of behavior, and antecedents of behavior. Our framework may be used to identify game principles which, in the future, might be used to predict which games are most likely to promote adoption and maintenance of leisure time physical activity.

Physical activity and dietary behavior change in Internet-based weight loss interventions: Comparing two multiple-behavior change indices

OBJECTIVE To investigate the effects of two Internet-based weight loss interventions on physical activity (PA) and dietary behaviors using two approaches for computing combined behavior change. METHOD Participants were 352 overweight/obese women and men completing 12-month interventions in San Diego, California during 2002-2007. Moderate-to-vigorous PA (MVPA) and sedentary time were measured with accelerometers, and dietary fat and fruit and vegetable intake were assessed with food frequency questionnaires. Longitudinal analyses tested the effect of the intervention on combined health behavior change quantified using a standardized residualized change index (SRCI) and a risk factor change index (RFCI). RESULTS At baseline, participants engaged in an average of 153 min/week of MVPA and 525 min/day of sedentary time, and consumed 37% of calories from fat and <3 fruits and vegetables per day. The interventions had a significant effect on combined behavior change as measured with each approach (p<0.001). The intervention effect was larger (p<0.001) when evaluated using the SRCI (standardized regression coefficient [Beta]=0.30) than the RFCI (β=-0.18). CONCLUSION Interventions that target both PA and dietary behaviors appear effective. The SRCI was more sensitive for evaluating the intervention, but the RFCI may be easier to use for communicating public health significance.

Personal informatics in the wild: hacking habits for health & happiness

Personal informatics is a class of systems that help people collect personal information to improve self-knowledge. Improving self-knowledge can foster self-insight and promote positive behaviors, such as healthy living and energy conservation. The development of personal informatics applications poses new challenges in human-computer interaction and creates opportunities for applications in various domains related to quality of life, such as fitness, nutrition, wellness, mental health, and sustainability. This workshop will continue the conversations from the 3 previous CHI workshops through discussions on practical lessons from previous research and development experiences. In particular, this workshop will extend this ongoing work through a focus on rapid prototyping and deployment in the wild. Topics covered will include designing interfaces for collecting and reflecting on personal data, building robust applications, and infrastructures to make applications easier to create.