A transdisciplinary model integrating genetic, physiological, and psychological correlates of voluntary exercise.

Abstract

Objective-Physical inactivity contributes to as many as 250,000 premature deaths per year (R. R. Pate et al., 1995). The authors' objective was to test a transdisciplinary model of the ways in which genetic variants, physiological factors, and psychological factors are thought to influence exercise with 64 healthy, regular exercisers.Design-In a within-subjects design, psychological and physiological responses to exercise were compared with responses to a sedentary activity.Main Outcome Measures-The authors measured affective state, perceived exertion, heart rate, and temperature change in response to moderate exercise versus sedentary activity. They also quantified genotypes on a single nucleotide polymorphism in the brain-derived neurotrophic factor (BDNF) gene.Results and Conclusions-The data show a relation between increases in positive affective states and acute exercise behavior, as opposed to a sedentary control. The BDNF gene moderated the effect of exercise on mood, heart rate, and perceived exertion. Physiological factors were, in turn, related to mood response, and mood response was a significant correlate of motivation to exercise in the future and of current exercise behavior. The model has potential as a framework for the basic study of the genetic, physiological, and psychological processes involved with voluntary exercise and as a tool for the applied examination of tailored exercise interventions and their efficacy for different subsets of individuals. Keywords exercise; transdisciplinary; genetics; physiology; mood Regular physical activity has been implicated in the prevention of cardiovascular disease and of a number of cancers including those of the colon, breast, endometrium, and prostate (Friedenreich, 2001;Kaaks & Lukanova, 2002;Pate et al., 1995). Recent reports estimate that approximately 30% of total cancer deaths are related to poor exercise and nutrition, and when taking into consideration both cardiovascular disease and cancer, that inactivity contributes to as many as 250,000 premature deaths per year (Pate et al., 1995). Despite the fact that the relation between poor exercise habits and morbidity and mortality has been well understood for some time, interventions designed to promote a healthier lifestyle have largely failed to One limitation of prior work in this area is the lack of an overarching theoretical framework that functionally links genetic, physiological, and psychological predictors of exercise behavior. In this research, we propose a transdisciplinary (Rosenfield, 1992) model of the ways in which genetic variants, physiological factors, and psychological factors are thought to influence exercise behavior (see Figure 1). In this broad framework, we hypothesized that the physiological effects (e.g., changes in body temperature, heart rate) of exercise influence the subjective experience of exercise (e.g., changes in mood, perceived exertion, perceived reward), which in turn are important determinants of motivation to exercise (e.g., higher selfefficacy for exer...

What keeps a body moving? The brain-derived neurotrophic factor val66met polymorphism and intrinsic motivation to exercise in humans

“…Notably, however, we did not find evidence that the relationship between BDNF genotype and the behavioral measure of intrinsic motivation is mediated by affective valence or positive affective response during the exercise, as BDNF genotype was not related to affective response in the current study. This finding is inconsistent with the results of Bryan et al (2007), who found that those with a met allele had a greater positive affective response to exercise. This may be due to a key methodological difference; in the Bryan et al study, exercise intensity was objectively controlled (at 65% of individual's predetermined VO2max), whereas participants in the current study chose the pace they felt was of a moderate intensity.…”

“…Due to the small number of participants with the met/met genotype, we collapsed across those with at least one copy of the met allele for between group comparisons as has been done in prior work (e.g., Bryan, et al, 2007;Bryan, et al, 2013;Gatt et al, 2009;Hariri et al, 2003;Jiang et al, 2013) and as is consistent with research on the BDNF SNP more broadly (Anastasia et al, 2013;Egan et al, 2003a;Kleim et al, 2006;Pezawas et al, 2004b;Szeszko et al, 2005).…”

“…Individuals with at least one copy of the met allele have been shown to have lower neuronal expression of BDNF , smaller hippocampal volume (e.g., Pezawas et al, 2004a), and impaired memory and hippocampal activation (Egan et al, 2003b). Interestingly, one study found that individuals with one copy of the met allele had a more positive mood response to a bout of moderate intensity exercise (65% of VO2max) Intrinsic Motivation and BDNF SNP 6 relative to those with a val/val genotype (Bryan et al, 2007). BDNF genotype has also been shown to moderate response to an exercise intervention (Bryan et al, 2013).…”

“…Individuals with the met allele have demonstrated a relatively more positive emotional response to exercise (Bryan et al, 2007); therefore we hypothesized that these individuals would also show greater intrinsic motivation (i.e., exercising for the enjoyment of participation) during a moderate bout of treadmill running. We further hypothesized that the relationship between genotype and intrinsic motivation would be mediated by affective response.…”

Menstrual Cycle Effects on Perceived Exertion and Pain During Exercise Among Sedentary Women

“…Consistent with established procedures 15,44 and our prior work, 45 Vo 2 max was assessed via online computer-assisted open-circuit spirometry during incremental treadmill exercise (Trackmaster 425 treadmill, Newton, KS). Oxygen levels were assessed using the Medgraphics Cardi02=CP system (St. Paul, MN).…”