Mindfulness meditation was used to reduce stress and its responses such as cortisol and C-reactive protein (CRP) among healthy and ill individuals in various cultures, but their effects have not yet been studied among Jordanian nursing students, experienced tremendous stress. Thus, the purpose of study was to examine the effects of three of such intervention on perceived stress (MM) on Trait mindfulness, perceived stress, cortisol, and CRP in Jordanian nursing students. The hypothesis was " mindfulness meditation will improve trait mindfulness, perceived stress, serum cortisol and serum CRP.

Using a Randomized controlled study conducted in a large university in Jordan, 108 nursing students were randomly assigned to experimental and control groups equally. The experimental group participated in 5 30-minute weekly sessions of mindfulness meditation. Trait mindfulness, perceived stress, serum cortisol, and CRP were measured at baseline and end of intervention.

Introduction Like nursing students in other countries, nursing students in Jordan have reported high stress, influencing students' health, academic performance, attrition, and ability to care for patients and themselves. Previous studies have shown that stress can negatively impact the body. Specifically, the immune system can be negatively impacted by the activation of the hypothalamic-pituitary-adrenal (HPA) system (e.g. cortisol). Elevated cortisol increases the release of pro-inflammatory factors such as C-reactive protein (CRP), found to be associated with a variety of chronic illnesses. Mindfulness meditation is a mind-body therapy that has been gaining increasing attention in the recent literature and has demonstrated promising results across different populations and settings. In Jordan, there is a lack of evidence related to the effectiveness of mindfulness meditation on stress and its physiological indices such as cortisol and CRP in Jordanian people generally and nursing students specifically. Thus, the aim was to examine the effects of three of such intervention on perceived stress (MM) on Trait mindfulness, perceived stress, cortisol, and CRP in Jordanian nursing students.

Participants and Setting The study sample included undergraduate nursing students who were selected using convenience sampling from Jordan University of Science and Technology (JUST).

Sample Size Calculation G* Power software 3.1 was used to calculate the required sample size, given a MANOVA test, an alpha of .05, power of 0.95, number of dependent variables of 4, number of groups of 2, and effect size of 0.25. A sample size of 80 was calculated, and an attrition rate of 35% was added based on a previous study with variables similar to those of the present study. Therefore, this resulted in a final total sample size of 108 participants.

Procedure First, approval from the institutional review board at JUST was obtained. After obtaining permission from the dean of the nursing college at JUST and the students' instructors, the PI visited the students in their classrooms. After the students' lecture had finished, the PI made an announcement explaining the study title and objectives and asked any students who were interested in participating to contact him either on the phone number assigned for the purposes of the study or via email. The PI arranged an initial meeting to meet with students who were interested in participating, which was to be held on another day in a private room at the university. At this meeting, the PI informed the students of the study objectives, risks, and benefits, in addition to answering the students' questions and assuring them that all collected data would be kept confidential. The students were also assured that they had the full right to refuse or discontinue participation at any time and that such refusal or discontinuation would not affect their academic achievement in any way. At the same meeting, informed consent was obtained from participants who agreed to participate and who met the eligibility criteria. After that, the participants were randomly assigned equally to the study groups using a computerized random numbers procedure carried out by a research assistant who was not involved in any other parts of the study. Finally, the dates and times of the sessions were determined.

In the 2-hour educational session, baseline measurements of the study variables were taken. Then, the PI delivered a PowerPoint presentation for the participants in each subgroup, as previously explained. At the end of the workshop, to avoid experimental contamination, the participants in each experimental group were asked not to share any information related to the intervention with the participants in the control group.

The actual training sessions were introduced to the participants in the experimental groups by the PI based on the ABC relaxation theory's guidelines and protocols. Based on the ABC Relaxation Theory, at least two, and preferably five, weekly sessions of actual mind-body training should be provided to evoke relaxation and optimize health. The sessions were held in a private, quiet, comfortable, and spacious room at the university. As previously mentioned, the dependent variables were measured twice, at baseline and at the end of the intervention (i.e., In the next morning after the 5th session).

Various strategies were followed to decrease measurement errors that could potentially be affected by variations in the data collection procedure. For example, filling out the questionnaire may be stressful for some subjects, hence influencing the objective measures. Therefore, the self-report measures were completed after the physical measures were taken. Also, all of the study measures in the intervention and control groups were taken in similar conditions, including similar room temperature and environment. In addition, quiet environments were maintained, with a "Do Not Disturb" sign placed on the doors of the rooms during the interventions and data collection.

Statistical Analysis Statistical analysis was conducted using SPSS software (version 25). Descriptive statistics were used to describe the sample. The sample and study variables were described by measures of central tendency and dispersion appropriate to the level of measurement. Initial independent t-tests and Chi-squared tests were conducted to ensure that the randomization across the covariates was successful, and one-way MANOVA was used to test the study hypotheses. Post hoc one-way ANOVAs were run to examine if there were significant differences in each of the dependent variables between the study groups. Due to multiple testing, the p-value was adjusted by dividing the p value of .05 by 4 (i.e., the number of dependent variables), with a level of .0125 considered as the level of significance for the ANOVA tests.

Inclusion Criteria:

• The study sample included undergraduate nursing students who were aged 18 years or over and taking a clinical course

Exclusion Criteria:

• Students were excluded if they were practicing any type of relaxation techniques or taking hypnotics, sedatives, anxiolytics, anti-depressants, or anti-hypertensive drugs.

The data (questionnaire and blood samples) were collected by three research assistants with at least 10 years nursing experiences who were not involved in any other parts of the study.

Also, the participants were randomly assigned equally to the study groups using a computerized random numbers procedure carried out by a research assistant who was not involved in any other parts of the study