Subcomponents of Negative Affect and Cortisol Reactivity
Affect refers to a state that represents how an object or situation impacts a person (Duncan & Barrett, 2007), and lies on two dimensions: valence (pleasantness - unpleasantness) and arousal (low to high physiological activation; e.g., Barrett, 1998). Prior research has found that affect is associated with stress, as measured by cortisol levels; however, these findings are inconsistent. On the one hand, self-reported negative affect has been found to be associated with both diurnal cortisol levels and the cortisol response to a stressor (e.g., Mikolajczak et al., 2008; Mendonca-De-Souza et al., 2007; Van Eck et al., 1996). On the other hand, other studies show no association between negative affect and diurnal cortisol (Polk et al., 2005; Schlotz et al., 2006). Furthermore, these prior studies investigating negative affect and cortisol have not separated the sub-components of affect by measuring the independent relation between either valence or arousal with cortisol level. We are interested in seeing if arousal and valence can function independently of each other, and if arousal alone is positively associated with increased cortisol levels.
We will investigate valence and arousal separately as they relate to diurnal cortisol level and the acute cortisol response to a stressor. We will also investigate the effect of breathing exercises in reducing the cortisol response to a laboratory stressor, as deep breathing is an effective method to reduce the stress response (Conrad et al., 2007). Consistent with prior work, we hypothesize that higher ratings of unpleasantness and arousal will be positively associated with the diurnal cortisol rhythm. We also hypothesize that laboratory stressor-induced changes in arousal and valence will be associated with changes in levels of cortisol from baseline. Finally, we hypothesize that the participants who do deep breathing exercises will show lower cortisol levels in response to the stressor compared to the participants who do not.
Supported by NIH-RCMI grant numbers MD007599 (formerly RR003037) and NIDA grant R25DA032520.