Do you constantly feel unmotivated to workout even though deep down you know you should get off the couch? Or are you someone for whom fitness is a way of life? The answer to this may lie in your genes. Recent research suggests that how a person feels in response to exercise may be in their genes and this response could in turn determine whether the person continues to pursue exercises a habit.
Affective response refers to an individual’s emotional response to a situation, for example pride experienced when winning something versus disappointment at losing, or pleasure vs displeasure. In this light, it becomes important to study how an individual feels during and after exercise. If someone finds it to be a highly enjoyable and pleasurable experience or experiences pride at accomplishing something, they would be more likely to pursue it continuously. And contrary to popular belief that exercise is enjoyable for everyone, there exist a significant number of people who do not find it pleasant or gratifying.
Psychologically, the principle of instrumental conditioning state that behavior can be modified by the reinforcing or inhibiting effect of its consequence that in turn increase or decrease the probability that the behavior will be performed again. If an individual experiences a net positive response to exercise over a period of time, they tend to engage more in the future. However, those with a net negative response, are more likely to participate less in the future. Those who have a net positive response are usually the ones who voluntarily engaged in exercise while those with an unfavorable response may have been pressured into exercising.
Now let us understand what factors determine whether we experience a positive or negative affective response.
During and shortly after exercise, we experience both aversive (negative or unmotivating) and appetitive (positive or encouraging) effects. Fatigue, muscle pain, respiratory exertion and monoamine depletion make up the averse effects. The fear of injuries or embarrassment can also cause aversion. Appetitive effects are experience when dopamine is released from the mesolimbic pathway, triggering motivation and desire. Other positive responses would be to experience a sense of accomplishment, distraction from anxiety and reduced sensitivity to stress.
Researchers have hypothesized that the way in which our genes respond to the above psychological effects of exercise could lead to the heritability of voluntary exercise behavior. A studyby Schutt et. al, was conducted to estimate how much of affective responses experienced in an adolescent population is due to genetic variation.
A large adolescent sample of twins and siblings were studied during and after exercise tests. The participants were then faced with a lifestyle interview. Their results confirmed that the responses to exercise could be partly genetic (varying between 12% and 37%). Genetic correlations were observed between voluntary exercise and affective responses of the participants. This goes to tell us that the reason why people feel differently about exercise is not solely the environment, but could be influenced by genetic factors too.
Several studies have already shown the connection between variations in Dopamine receptor gene (DRD2) and binge eating, obesity and linguistic abilities.
Genetics plays an important role in determining if an individual will voluntarily indulge in exercise and whether or not they feel good after exercising. Knowing this information can help in identifying motivating or demotivating factors.