## 4 Discussion
To overcome this barrier, they decided to embed biofeedback in a virtual natural setting that is enjoyable, offers meaningful biofeedback elements, and promotes involuntary attention toward the environment. Their results highlighted the positive changes on anxiety scores and relaxation self-efficacy. The positive and promising outcomes of such systems can also be identified in other studies. For instance, [PERSON] et al. [90] showed in their pilot study that DEEP, a novel VR biofeedback game that involves deep diaphragmatic breathing, could effectively reduce physiological arousal that was being produced by an intense stressor. Moreover, in their study, [PERSON] at al. [91] indicated the positive effect of a VR application on reducing stress and anxiety in a clinical pediatric hospital, comprising among others breathing exercises and minigames with interactive animations and objects. In recent years the development and implementation of serious game-biofeedback applications to promote self-management and mental well-being has been growing [92; 93] and may be the future in VR interventions for stress management. However, these applications with game elements should be further examined for their effectiveness in laboratory premises as well as in mental health interventions. These results uncover VR systems' flexibility to be combined with other elements, such as biofeedback, or to be integrated into other concepts with a more traditional psychological background in order to produce significant psychophysiological effects. Among the retrieved studies, the paper of [PERSON] et al. [35] has attracted attention as they employed immersive VR along with coping strategies derived from cognitive behavioral therapy approaches, such as self-monitoring, relaxation training, and guided imaginary experience. It is worth mentioning that their stress management protocol was held in different sessions, eliciting a significant reduction in cardiac activity after the sessions as well as in follow-up. Cognitive behavioral interventions and mindfulness-based exercises, which facilitate the active adaptation of responses to stresses, have been commonly adopted from prevention programs, for example, in occupational settings to reduce stress [24; 25]. Employees can learn to manage adverse reactions to stressful events by bringing about a mental and/or physical state that is opposite to the psychophysiological arousal evoked by stress [25]. The goal is primarily to direct employees' attention to a stimulus and prevent distraction from irritating thoughts or the environment [94]. These cognitive mechanisms underlie two fundamental components: _attentional awareness_ that makes possible attention regulation and _perspective shifting_ that enables a person to reappraise beliefs and reactions with curiosity and acceptance. An important outcome of the latter is _decentering_, a cognitive ability that inhibits the elaborative processing of experienced stressors and, thereby, decreases immersion and mental traveling to them [95; 96]. Although these mental interventions can be beneficial to stressed individuals, they do also have some complexity, e.g., it might be hard at first to regulate negative feelings, that may cause frustration and negative feedback experiences. Pleasant virtual environments can promote users' awareness toward their responses, while they are practicing stress management techniques at their own pace and involuntarily focusing their attention on fascinating elements. Furthermore, immersive settings that are attractive and stimulate users' attention may be a way of increasing adherence to prevention programs; a main problem that concerns researchers in the area of prevention and population's mental health. Intervention adherence that reflects treatment engagement, is a key mechanism in psychological programs and is positively associated with intervention outcomes [97].