Creating Behavioral Vacuums

Abstract

Screen media use has increased dramatically in children in the past decade, contributing to increasing rates of sedentary behavior in children. Excessive screen media use is related to poor social skills and increased likelihood of being overweight and obese. Behavioral economic theory has been used to examine the relationship between sedentary behavior and physical activity and whether an increase or decrease in one leads to a reciprocal response in the other. Health care providers should be aware of the behavioral “vacuum” that is created when patients are told to decrease sedentary behavior and assist patients with filling that void with nonsedentary behaviors.

“Physiological benefits and consequences are distinctly different between PA [physical activity] and sedentary behaviors.”

National guidelines recommend that youth engage in 1 hour of physical activity (PA) each day.^1,2 Youth with daily PA have improved academic performance,^3,4 mental health, ⁵ and cardiovascular outcomes. ⁶ Consistent with the article in this issue by Sacheck and Hall, ⁷ the message in terms of PA should likely be the more, the better. While it is often assumed that children are currently engaging in less PA and consuming more calories than in previous generations, studies do not clearly support this perception.^8-11 However, obesity rates have quadrupled in the past 30 years. ¹² This disconnect shifted some investigators to focus on behaviors outside of structured exercise periods.

Even if youth followed the national guidelines for PA, time outside of PA (non-PA time) would make up the vast majority of the day. ¹³ Non-PA time can be subdivided into sedentary activities (eg, sitting, reclining, watching TV) and nonsedentary activities (eg, shopping, doing homework, working outside). It is a common misconception that increasing PA will result in decreasing sedentary behaviors; however, this is not necessarily the case. For example, it is possible to meet the ≥1-hour PA recommendation but not meet the sedentary recommendation of 2 hours or less of electronic screen time (eg, texting, watching television, playing videogames) daily. ¹⁴ Along with increasing rates of obesity, youth’s screen media use has changed dramatically in recent decades. ¹⁵ From 1999 to 2009, computer use more than tripled (27 vs 89 minutes per day) and overall media use increased by 21%. ¹⁶ Currently, youth spend an average of 8 hours per day engaged in sedentary behaviors either during or outside of school. ²

Physiological benefits and consequences are distinctly different between PA and sedentary behaviors. ¹³ There is increasing evidence suggesting that sedentary behaviors such as screen media use are associated with both health and psychosocial consequences. Specifically excessive screen media use has been shown to result in poorer social skills when compared with children who received similar amounts of direct person-to-person contact. ¹⁷ In terms of health consequences, there is a significantly higher odds for incident obesity in youth with greater screen time hours during adolescence. ¹⁸ Even in those who consumed healthy diets and who engaged in PA, more than two hours of sedentary activities per day place youth at risk for increased body mass index and body fat, ¹⁹ resulting in elevated chronic disease risk.^13,20,21 Clear associations have also been established between increased screen time and poor eating behaviors.^17,22,23

Behavioral Economics

The theory of behavioral economics posits that as one behavior is decreased a vacuum is created, which will be filled by another behavior, increasing the frequency of that behavior. This theory has been used to study the relationship between sedentary behavior and PA. ²⁴ In a 2-year study of families with obese children, investigators compared targeting a decrease in sedentary behavior to targeting an increase in PA and the resulting impact of sedentary and physical activity. ²⁵ Some children exchanged one sedentary behavior for another while other children exchanged sedentary behavior for PA or nonsedentary time (eg, playing). The choice for PA in lieu of another sedentary behavior depended on personal preference as well as access and availability to alternative PA. In order to encourage less sedentary behavior, youth need a wide variety of available and enjoyable active choices. ²⁵

Overall, reducing sedentary behavior did not necessarily result in an improvement in PA. Essentially by decreasing sedentary behavior, a “vacuum” was created which children had to fill with another behavior. Much of the work of health care professionals (HCP) in lifestyle medicine either encourages increasing or decreasing a behavior. It is imperative that HCPs carefully consider the impact that changing a behavior has on other areas of a person’s life. Because we are constantly “behaving,” when a HCP encourages a patient to decrease a behavior, another behavior necessarily replaces it and fills in the behavioral vacuum that was created. In the absence of guidance on behaviors to engage in instead of the targeted sedentary behavior, many children will replace the identified sedentary behavior with another sedentary behavior. Likewise when a HCP encourages a patient to increase a behavior, inherently another behavior decreases. It is equally important to discuss which behaviors will be reduced when asking a patient to increase a specific behavior.

The concepts of behavioral economics and behavioral substitution apply not only to PA and sedentary behavior, but other health behaviors as well. For example, when counseling patients about eating habits or smoking behaviors, it is important to not only recommend decreasing/increasing the behavior (eg, consumption of fried foods, consumption of fruits, or cigarette smoking), but to address the behaviors the patient will replace the undesirable behavior with or reduce to accommodate the new targeted behavior. HCPs may consider having patients track the targeted behavior and other competing behaviors in order to ensure that acceptable other behaviors are being increased/decreased in order to improve targeted behaviors. For example when focusing on increasing fruit and vegetable consumption, physicians might also track dietary intake overall to ensure that fruit and vegetable consumption replaces consumption of foods high in calories as opposed to replacing consumption of low-fat dairy and lean proteins.

Several studies clarify this point. Overall, evidence suggests that increasing sedentary behavior results in decreased PA, but decreasing sedentary behavior has a minimal effect on PA. ²⁶ This is particularly common among girls who are likely to substitute sedentary behavior for another sedentary behavior while boys are more likely to substitute PA for sedentary behaviors. ²⁷ In this case, increasing sedentary is likely to “push out” PA behaviors from a child’s daily routine. However, focusing on decreasing sedentary behaviors alone will not likely result in increases in PA. This evidence further supports the concept that sedentary behaviors and PA should be viewed separately and underscores the importance of discussing the behaviors that will replace targeted behaviors.

Both reinforcement and stimulus control have been shown to be a means of reducing sedentary behaviors in children. ²⁴ Some examples of stimulus control (ie, changing their environment to prevent engaging in sedentary behaviors) include unplugging the television, watching television only during specified times, and completing homework prior to videogame use. Again, youth who substituted PA for sedentary behaviors had greater z–body mass index changes at 12 months compared with those who did not (−1.05 vs −0.51, P < .001) providing additional support for targeting both decreasing sedentary behaviors and increasing PA. ²⁴

Clinical Applications

The findings in behavioral economics provide 2 important points for HCPs. First, while encouraging patients to obtain 1 hour or greater of recommended PA is important, it is equally important to focus on the other 23 hours of the day. For example, instead of asking patients, “Do you exercise?” and receiving a yes/no response, providers also need to ask “What else do you do the rest of the day?” or “About how many hours do you think you spend sitting such as playing videogames or watching television?” Second, when making recommendations to reduce a behavior such as sedentary behavior, it is important to talk with patients about behaviors they might use as a substitute. While ideally moderate to vigorous PA could be used as a substitute, this may not be a realistic option when asking patients to reduce sedentary behavior by several hours. As a result, patients need help determining other behaviors such as gardening, cleaning, or walking that they can do to fill this vacuum in order to avoid substitution with another sedentary behavior.

Conclusion

The youth obesity epidemic has led to scientists to rethink their approach to weight loss and overall health in youth. Though PA is an important part of health and wellness, analyzing sedentary behaviors is similarly important. Reducing sedentary behaviors, targeting time outside of PA strategies, and incorporating strategies for stimuli reduction and reinforcement are favorable methods to improve health care in youth.