Intrinsic Reward Helps Make Exercise a Habit

Summary: New research supports the role of intrinsic reward in turning exercise into a lasting habit.

Source: Iowa State University.

The morning alarm can be more than a wake-up call—it can be the cue that triggers a workout. But when exercise is not yet a habit, that same alarm can spark a brief internal debate: get up and exercise or go back to sleep?

Research led by L. Alison Phillips, an assistant professor of psychology at Iowa State University, shows that a cue alone is rarely enough to establish a lasting exercise routine. Rather, consistent cues (for example, a morning alarm or the end of the workday) must be paired with intrinsic rewards—positive, internally experienced outcomes such as enjoyment, stress reduction, or meaningful social connection—for exercise to become automatic.

When exercise produces intrinsic reward, people stop having to weigh the pros and cons each time the cue appears. Instead of a chore that requires willpower, exercise becomes a response you want to perform. “If someone doesn’t like to exercise it’s always going to take convincing,” Phillips says. “People are more likely to stick with exercise if they don’t have to deliberate about whether or not to do it.”

Intrinsic reward varies by individual. For some it is physiological—endorphins, improved mood, or reduced stress. For others it is social—enjoying time with a friend during a workout. Importantly, intrinsic reward often takes time to develop. Most people don’t fall in love with exercise immediately; repeated experience is usually necessary before the activity itself becomes rewarding. If the activity does not produce any direct, felt benefit, people will likely choose other activities when a decision point arises.

Why exercise habit formation is different

Exercise is a complex, effortful behavior. That complexity makes it harder to automate than simple routines like brushing your teeth. Because exercise requires substantial energy and commitment, the reward supporting habit formation needs to come from the activity itself. External goals—losing weight or meeting a performance target—can motivate someone to start exercising, but such extrinsic reasons may not be enough to sustain automatic exercise behavior over the long term. If the external outcomes lag or change, motivation can fade.

Initiators and maintainers

Phillips and colleagues compared two groups: initiators (people who are just starting to exercise) and maintainers (people who have been exercising regularly for at least three months). They ran two studies: the first relied on self-reported exercise duration and intensity, while the second used accelerometers to objectively track activity.

The relationship between intrinsic reward and exercise differed by stage. For initiators, enjoying exercise increased the likelihood of continuing, but continuation still depended largely on deliberate intention. For maintainers—those further along in their routine—intrinsic reward appeared to support habit strength, making the response to cues more automatic. In other words, intrinsic rewards help motivate new exercisers through conscious intentions, but they sustain regular exercisers by reinforcing habitual action.

The findings are reported in the journal Sport, Exercise and Performance Psychology and suggest that fostering intrinsic reward is a promising route to long-term exercise maintenance.

Even when a cue and intrinsic reward exist, maintaining an exercise habit requires ongoing commitment. Life changes—a new job, moving, or the arrival of a child—can disrupt routines, and sustaining or forming new habits in those circumstances takes renewed effort.

Teaching and promoting habit

Knowing that exercise is healthy is not enough to make it habitual. Phillips argues for an approach that helps each person discover the intrinsic rewards that make exercise appealing to them. To that end, she and other researchers at Iowa State are developing an intervention modeled in part on diabetes prevention programs. The intervention will guide people to notice and amplify the immediate, internal benefits of exercise and to use consistent cues that support repetition.

Early plans for the intervention include a mix of personal coaching and group activities, which can help participants identify what they find rewarding—whether it’s the mood lift after a run, the social interaction of a class, or the sense of accomplishment from improving performance. Helping individuals experience and recognize these intrinsic rewards may be the missing piece in long-term habit formation.

“What we’re aiming for is lifestyle change,” Phillips says. “Interventions to date have not reliably produced long-term lifestyle change. There are simple strategies that have not yet been tried to help people develop exercise habits for life. Although the strategies may be easy to describe, implementing and sticking to them can be very difficult. It’s a classic high-risk, high-reward endeavor.”

Research details and abstract

The research article is titled “Intrinsic Rewards Predict Exercise via Behavioral Intentions for Initiators but via Habit Strength for Maintainers.” The studies measured stage of exercise (initiation vs. maintenance), intrinsic exercise rewards (enjoyment, stress reduction), behavioral intentions, and habit strength. Study 1 used self-reported exercise among a large sample of U.S. college students (n = 463). Study 2 used accelerometer data over one month in a university population (n = 114).

Results showed that for maintainers, habit strength mediated the relationship between intrinsic rewards and exercise. For initiators, intentions mediated that relationship. The authors conclude that intrinsic rewards can promote exercise initially through reflective, intentional processes and later through automatic, habitual processes. Interventions that help people experience intrinsic exercise rewards may therefore support long-term exercise maintenance.

Original research citation: Phillips, L. Alison; Chamberland, Pier-Éric; Hekler, Eric B.; Abrams, Jessica; and Eisenberg, Miriam H. “Intrinsic Rewards Predict Exercise via Behavioral Intentions for Initiators but via Habit Strength for Maintainers.” Sport, Exercise and Performance Psychology. Published online August 29, 2016. DOI: 10.1037/spy0000071.

Keywords: exercise habit, intrinsic reward, habit formation, exercise maintenance, intrinsic motivation, behavioral intentions, physical activity.