INTRODUCTION
illness, gastrointestinal problems, anxiety, psycho-emotional illness, psychiatric, CBKF
Nursing is carried out by professional categories that, although distinct, work interconnected in a wide variety of environments, and is present 24 hours a day, 365 days a year in the hospital network. Although work plays an important role in meeting basic needs and insertion in society, in nursing, there are stressors resulting from physical and mental loads, a fact that can cause illness in workersWorldwide, stress is among the greatest health problems as adjunct in various physical and psycho-emotional pathologies, such as gastrointestinal problems and anxiety. Occupational stress can be defined as a process in which individuals perceive work demands as stressors, which, when exceeding their coping ability, provoke negative reactions in the subject, constituting a subjective phenomenonCardiovascular biofeedback (CBKF) tools, whose self-regulation and self-control processes occur through the man-machine interface, have been gaining visibility as a non-drug therapy, isolated or combined with other therapies. Investing in interventions that strengthen workers individually and in work environments can be a strategy for reducing psycho-emotional illness. Research has shown that CBKF techniques are effective in managing stress in different populations, and can help strengthen strategies for coping with adverse situationsThe CBKF technique also provides heart rate variability (HRV) measurement and assessment, a biomarker that corresponds to the natural variation that occurs between heart beats or pulses, and is closely linked to hormonal response and autonomic nervous system (ANS) adaptation, triggered when the body is exposed to a stressor. Changes in HRV patterns provide a sensitive and early indicator of health impairments. A high variability in heart rate is a sign of good adaptation, characterizing a healthy individual with efficient autonomic mechanismsStudies on using CBKF in nursing professionals and its benefits in this group are still scarce as well as in other categories of health workers. In 2017, a clinical trial tested CBKF on 135 nurses working in a psychiatric unit in three hospitals in Taiwan, demonstrating a significant reduction in occupational stressThus, the study is justified by the need to develop skills that reduce stress, minimizing the risk of psycho-emotional illness. Therefore, the following research question emerged: what is the effect of CBKF on hospital nursing staff stress when compared to a placebo activity without self-monitoring?