Regular exercise protects against overweight/obesity as well numerous chronic diseases. Yet, less than half of Americans exercise sufficiently. Elevated levels of depressive symptoms have been identified as an important correlate of physical inactivity as well as poor adherence to exercise programs. Individuals with depression are less sensitive to rewards, demonstrate an attentional bias toward negative stimuli, and have lower baseline levels of activation of the left frontal cortex ? which may place them at increased risk for effectively managing the affective experience of exercise. Indeed, engagement in bouts of exercise consistently results in changes in affect and, importantly, these affective experiences (especially positive affect) predict current and long-term levels of physical activity. Whether an individual is able to manage the interoceptive cues associated with increased levels of physical exertion or shift attention away from the negative aspects of exercise appears to influence the affective experience during exercise. Yet, relatively little attention has been given toward improving the affective experience of exercise in the general population, much less among individuals with affective vulnerabilities who are at greater risk for insufficient activity levels. Transcranial direct current stimulation (tDCS) is a relatively safe form of noninvasive brain stimulation, which has shown promise in impacting a variety of cognitive and affective processes in a large number of individuals, including those with depression. tDCS uses low current electricity to modulate neuronal activity in targeted brain areas via two electrodes placed on the head. tDCS targeting the left dorsolateral prefrontal cortex (DLPFC), specifically, has shown promise in improving emotion regulation. Experimental studies of tDCS targeting DLPFC have resulted in lower perceived emotional valence toward negative stimuli, improved frustration tolerance and decreases in attentional bias to negative emotional stimuli. When paired with exercise, those receiving tDCS experience a slower rate of perceived exertion (RPE) during exercise. There is also increased interest in testing neuromodulation approaches such as brain stimulation techniques in obesity prevention efforts (see PA-15-163). We propose to conduct a pilot randomized controlled trial of tDCS versus sham delivered 3x/week for 8 weeks in the context of supervised aerobic exercise (AE) program among 60 low-active individuals with elevated depressive symptoms. Follow-up assessments will be conducted at end of treatment, 3-, and 6-months to examine changes in levels objective-measured moderate-to-vigorous physical activity (MVPA). Therefore, tDCS would be a highly novel and potentially promising approach toward improving the affective experience of exercise and thereby increase exercise adherence among individuals with depressive symptoms. This, in turn, would have high public health impact on preventing obesity and chronic diseases among these at-risk individuals.
Elevated levels of depressive symptoms have been identified as an important correlate of physical inactivity as well as poor adherence to exercise programs. Individuals with depression may be less able to regulate the affective experience of exercise leading to poor adherence in the long-term. Transcranial direct current stimulation (tDCS) is a relatively safe form of noninvasive brain stimulation, which has shown promise in improving emotion regulation in a large number of individuals. If the results of the current project demonstrate an efficacy for tDCS, individuals who struggle with enjoying exercise could be afforded with a practical option for increasing and maintaining physical activity levels. This, in turn, would have high public health impact on preventing obesity and concomitant chronic disease among physically inactive individuals.
