نقش تحت تاثیر و نشخوار فکری در بهبود قلبی و عروقی استرس

This study examined the psychological processes that may impede or facilitate cardiovascular recovery. It was hypothesized that cardiovascular recovery would be hampered by negative affect and rumination, and facilitated by positive affect. In an experimental study, stress was elicited by exposing participants (N = 110) to a mental arithmetic task with harassment. After the stress task, affective levels were manipulated via a movie scene with negative, neutral, or positive emotional valence, or without an affect manipulation (control condition). During the entire experiment, heart rate and systolic and diastolic blood pressure levels were measured continuously. Results indicated that blood pressure recovery was hampered by the negative affect manipulation and by rumination. However, the positive affect manipulation did not facilitate blood pressure recovery. No effects were found on heart rate recovery. In sum, the findings emphasize the importance of negative affect and rumination in stress recovery.

It is widely accepted that stress adversely affects individual health. For example, a longitudinal research has demonstrated that exposure to psychosocial risk factors at work is associated with increased physical and psychological health problems among employees over time (Belkic et al., 2004, Chandola et al., 2008 and Kivimäki et al., 2006). Still, the mechanisms that cause such adverse health effects remain poorly understood. This is possibly due to the predominant focus on physiological ‘reactivity’ to stressors: physiological responses that occur while the stressor is present. Only limited attention has been paid to physiological ‘recovery’ after exposure to stressors, that is, physiological responses that prolong or (re)occur when the stressor is no longer present (Linden et al., 1997 and Schwartz et al., 2003). Over the last decade, awareness has risen that recovering from stress is an essential part of a healthy life style. Longitudinal studies have yielded evidence that poor recovery is related to serious health threats such as hypertension (Hocking Schuler and O'Brein, 1997), and even cardiovascular death (Kivimäki et al., 2006). Recovery is also a better predictor of long-term increases in blood pressure than mere reactivity to stressors (Steptoe and Marmot, 2005). Therefore, recovery is seen as a vital link between acute physiological responses to job stressors and employee health (Geurts and Sonnentag, 2006). The crucial role of incomplete recovery from stress can be understood from the perspective of Effort-Recovery (E-R) theory (Meijman and Mulder, 1998). A core assumption of this theory is that dealing with high demands or stressors requires effort which is mobilized by activation of the Sympathetic-Adrenal-Medullary (SAM) system that, amongst others, regulates cardiovascular activity. E-R theory posits that health is not at risk as long as the physiological activation disappears shortly after the stressor had ended—and thus complete recovery occurs—(Meijman and Mulder, 1998). However, when physiological stress responses prolong and sympathetic activation no longer returns to and stabilizes at a pre-stressor level, the total load on the individual exceeds homeostatic capacity. Such a state is referred to as ‘allostatic load’ (McEwen, 1998), and includes a disturbed sympathetic–parasympathetic balance that is an important factor in the development of later hypertension and cardiovascular disease (Brosschot and Thayer, 1998 and Thayer et al., 2010). The present study focused on cardiovascular recovery after stress exposure. Specifically, we examined the role of affect and rumination in the recovery process. 1.1. The role of affect in stress recovery Various field diary studies on recovery have provided indirect evidence for the impact of negative and positive affect on the process of stress recovery. For instance, a higher level of negative affect after a work day was associated with higher need for recovery before bedtime (Sonnentag and Zijlstra, 2006). Recently, Van Hooff et al. (2011) investigated among university faculty members to what extent subjective parameters of recovery (i.e., fatigue and vigor) at the end of the working day and before bedtime were influenced by positive affect experienced during work and during off-job time. They showed that the experience of pleasure at work and during off-job time had favorable effects on recovery at the end of the working day and before bedtime. Although these studies demonstrate the impact of affective states on subjective recovery, it remains unclear to what extent affective states are related to cardiovascular recovery as well. Overall, research suggests that negative affect, or feelings of distress, are associated with prolonged stress-related cardiovascular activation, and thus slower cardiovascular recovery (for reviews: Chida and Hamer, 2008 and Pieper and Brosschot, 2005). In two real life studies, cardiovascular activity was prolonged between 5 and 45 min after negative emotional episodes, independently of initial response, posture, physical activity, talking, alcohol intake, and other biobehavioral variables (Brosschot and Thayer, 2003 and Kamarck et al., 1998). Although these field studies provided evidence for the hampering impact of negative affect on cardiovascular recovery from stress, the role of positive affect in the process of cardiovascular recovery is less clear. A few laboratory studies with experimentally induced stressors investigated the role of positive affect in stress recovery. A laboratory study in which participants had to answer a difficult statistical question showed that a general positive mood was associated with more complete cardiovascular and subjective post-stress recovery, independent of negative affect. In contrast, a more positive affective state during anticipation of the challenge was related to poorer cardiovascular recovery (Papousek et al., 2010). Another laboratory study on the role of positive and negative affect in stress recovery took a different approach by manipulating affective states after a stressful task (a 60-s speech preparation task). After this stressful task, participants watched 100-s film clips with different emotional valence. Results revealed that a positive affect manipulation facilitated cardiovascular recovery as opposed to a negative affect manipulation (Fredrickson et al., 2000). The study by Fredrickson et al. (2000) is the only experimental study examining the role of both positive and negative affect in the process of cardiovascular recovery from stress. However, they examined the anticipation of a stressor and did not examine the experience of a real stressor. After the speech preparation task, all participants were ‘by chance’ selected to watch a video clip and knew that they did not have to actually deliver their speech. In this way the stressor was ended immediately, which may have influenced the recovery process. The current laboratory study investigated to what extent affective processes hamper or facilitate cardiovascular recovery from a stressful task. After exposure to a stressful event an affective manipulation took place by showing participants a movie with either a negative, neutral, or positive emotional valence, or without an affect manipulation (the control condition). We hypothesized that cardiovascular recovery after stress exposure is slower during the negative affect manipulation (Hypothesis 1), and faster during the positive affect manipulation (Hypothesis 2), than during the neutral affect manipulation.