Introduction

Medical students experience higher stress levels, which can lead to many health problems. Evidence shows that compared to the general population, medical students have poor health status1,2. This is explained as medical students have higher levels of academic stress and psychosocial pressure3. Increased stress levels among medical students contribute to an increased risk of cardiovascular and metabolic syndrome and a decrease in immune parameters, including Immunoglobulin A (IgA), Immunoglobulin G (IgG), and Immunoglobulin M (IgM)4,5. The body’s natural reaction to stress is a “fight or flight” response, characterized by an increased level of hormone release, elevated blood pressure, and heart rate6. Preparation of the body for quick reaction from short-term danger, for example, in the case of medical students, exams, clinical responsibilities, or more high-pressure tasks. However, these activations can be problematic if they continue over time7. Evidence shows that medical students face long-term stress due to their training demands, academic pressure, etc.2. This type of chronic stress does not need any physical response and possibly has a high level of health consequences8. A substantial number of evidence has shown that psychological challenges can potentially change the features of the immune response4. IgM, IgA, and IgG are serum immunoglobulin, an integral component of the adaptive immune system9. IgA and IgG are long-lasting binding antibodies that provide mucosal immunity, while IgM is involved in tissue homeostasis and provides a rapid immune response10,11. Prolonged stress can decrease immune parameters, for example, IgA, IgG, and IgM, which results in weakening the body’s defense against any type of infection. This may lead to medical students being more susceptible to health diseases12.

Chronic stress can also cause elevated lipid profiles and disrupted glucose parameters13. These changes in metabolic health are potential risk factors for many chronic diseases, including cardiovascular disease, polycystic ovarian syndrome, thyroid problems, and type 2 diabetes14,15,16. It is important to understand these challenges do not only have a severe impact on student’s academic performance but also on their health. This evidence shows the need for educational institutions offering medical programs to prioritize the implementation of stress management techniques for students as well as integrate curriculum reform17. Numerous studies show that yoga is a successful stress management technique that helps reduce chronic stress and improve an individual’s overall health18,19,20. In addition to its psychological aspects, the physical benefits of yoga can also positively impact metabolic health. Yoga exercises have been shown to improve insulin resistance, lipid profiles, and overall fitness. For example, a recent study21 found that yoga was as effective as moderate-intensity aerobic training in improving irisin levels and insulin resistance in women with type 2 diabetes. These physiological effects are particularly important for medical students, a population that often deals with high stress and a sedentary lifestyle is widely used as a type of mind-body therapy and also as a stress management technique in treating the risks of chronic disease22.

Systematic review shows adults suffering from anxiety and depression disorder improve their overall health through yoga intervention23. Studies have clearly shown that yoga has a positive impact on insulin resistance, lipid profile, and glycemic control24. Additionally, the influence of yoga is proven on the autonomic nervous system, which is very important in regulating the metabolic process25. A recent meta-analysis26 shows a decrease in Fasting Plasma Glucose (FPG), low-density lipoprotein cholesterol (LDL-C), total cholesterol (TC), and triglycerides as well as HbA1c and body weight in people with T2DM practicing yoga exercise compared to those who engage in daily exercise26,27.

It is known that medical students have low levels of physical activity and high levels of sedentary behaviors, especially among female students28. Yoga training, in the beginning, involves asanas, which are slow and stationary, for muscle training, which is connected with breathing29. This type of intervention can be performed by people with a longer sedentary lifestyle, who are overweight, etc.30. It is proven that yoga is the most effective and earliest clod of providing a calm and peaceful mind30,31,32. Although research has demonstrated a link between stress and poor health outcomes in medical students, and the potential benefits of different types of yoga practices, a significant gap remains in the literature. However, many studies have shown that yoga can positively impact metabolic parameters such as insulin resistance and lipid profiles24,25. Some studies have established that chronic stress can alter immune markers like IgA, IgG, and IgM4,5. Despite this evidence, there is a lack of comprehensive research exploring the effects of a yoga intervention on both immune and metabolic parameters within a common population that suffers a similar stressful environment but without explicit stress analysis.

The Primary objective of the current study is to explore the effect of 10 weeks of yoga intervention on the Immune parameters IgA, IgG, and IgM among medical students. Based on the evidence, the secondary objective is to explore the metabolic parameters after 10 weeks of yoga intervention among medical students. Findings from the current study would help medical students improve their stress management and overall health.

Results

Participants

Thirty-seven out of seventy-five participants expressed interest in participating in the current study. After collecting the baseline data and beginning the intervention, two participants were excluded due to lack of presence in the intervention. This results in thirty-five participants who completed the study. The characteristics of the study population are shown in Table 1.

Table 1 Characteristics of study populations.
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The average of the included participants is 21.84 ± 2.67 years and a BMI of 22.56 ± 3.85 kg/m2. The medium height and weight of the participants are 168 cm (154–190) and 65 kg (45–95), respectively. Among the total participants in the current study, 81.1% were female and 18.9% were male. 83.8% were living in the city, 5.4% in the capital,5.4% in the countryside, and 5.4% in the village. 43.2% of students from the first year, 40.5% from the second year, and 16.2% from the third year of their major participated in the current study. All the markers from pre- and post-data fell within the normal range. See Table 2.

Table 2 Mean and standard deviation of immune and metabolic parameters before and after 10 weeks of yoga intervention in participants.
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Primary outcomes: changes in immune parameters

Based on the blood test, The level of IgA increased significantly from a pre-intervention mean of 1.90 ± 0.85 g/l to a post-intervention mean of 2.20 ± 2.35 g/l (mean difference: 0.30 ± 2.30 g/l, p < 0.001) (Tables 2 and 3). This increase was associated with a strong effect size (r=-0.702). The level of IgG showed a slight but significant decrease from a pre-intervention mean of 1.90 ± 0.85 g/l to a post-intervention mean of 1.90 ± 0.85 g/l (mean difference: -0.80 ± 1.04 g/l, p < 0.01). The effect size for this change was moderate (d = 0.771). Similarly, the level of IgM increased significantly from a pre-intervention mean of 1.08 ± 0.41 g/l to a post-intervention mean of 1.15 ± 0.42 g/l (mean difference: 0.07 ± 0.11 g/l, p = 0.001). The effect size for the change in IgM was small (d = 0.002). Table 3.

Table 3 The mean change of immune parameters after 10 weeks of yoga intervention in participants.
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Secondary outcome: changes in metabolic parameter

Changes in Metabolic Parameter The level of HbA1C increased from 5.25 ± 0.21% to 5.29 ± 0.27% (mean difference − 0.03 ± 0.18%, p = 0.360) (Tables 2 and 4), with a small negative effect size (d -0.157). Similarly, HbA1C_IFCC increased from 33.91 ± 2.38 mmol/l to 34.29 ± 2.94 mmol/l (mean difference − 0.37 ± 2.06 mmol/l, p = 0.293), with a small effect size (d -0.180). Fasting blood glucose (FBG) levels increased from a pre-intervention mean of 4.88 ± 0.47 mmol/l to a post-intervention mean of 4.99 ± 0.31 mmol/l (mean difference: 0.122 ± 0.39 mmol/l, p = 0.10), and the small effect size (r = 0.278). Total cholesterol levels decreased from a pre-intervention mean of 4.41 ± 0.84 mmol/l to a post-intervention mean of 4.38 ± 0.71 mmol/l (mean difference: 0.04 ± 0.37 mmol/l, p = 0.554), with a small positive effect size (d 0.101). Triglyceride (TGC) levels decreased from a pre-intervention mean of 0.97 ± 0.42 mmol/l to a post-intervention mean of 0.91 ± 0.43 mmol/l (mean difference − 0.05 ± 0.31 mmol/l, p = 0.298), and the effect size (r -0.176) was small and negative. HDL levels significantly increased from a pre-intervention mean of 1.53 ± 0.41 mmol/l to a post-intervention mean of 1.59 ± 0.32 mmol/l (mean difference: 0.06 ± 0.19 mmol/l, p = 0.005), with a negative effect size (d -0.474). LDL levels increased from a pre-intervention mean of 2.57 ± 0.69 mmol/l to a post-intervention mean of 2.66 ± 0.65 mmol/l (mean difference: 0.09 ± 0.36 mmol/l, p = 0.14), with a small negative effect size (d -0.251). Non-HDL levels decreased from a pre-intervention mean of 2.87 ± 0.77 mmol/l to a post-intervention mean of 2.78 ± 0.69 mmol/l (mean difference: -0.09 ± 0.40 mmol/l, p = 0.214), and the effect size was moderate and positive (d = 0.214). The result is shown in Table 4.

Table 4 Mean change of a metabolic parameter after 10 weeks of yoga intervention in participants:
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Discussion

The finding of the current research shows that medical students who participated in the 10-week yoga intervention with GSY protocol18 significantly improved their IgA levels and HDL levels among medical students is contributing uniqueness to the existing research. It is important to note that the post-intervention data was collected when the participants were close to their exam period, and all the reported outcome measures fell within the normal range. It has been proven that close to the exam period; students have high stress levels, hence the low IgA level33,34. The results of the current study are important for the healthcare profession and university management for providing stress management techniques for medical students.

Immune parameter

The average level of IgA significantly increased (p < 0.001) after the 10 weeks of yoga intervention, showing that yoga plays an important role in improving the participants’ immunity. Additionally, the strong effect size of (r=-0.702) between IgA level and yoga intervention presented a consistent effect of yoga on immune health. This result is supported by the study among older adults where the concentration of secretory immunoglobulin A and secretion were increased after the yoga intervention35. A study on pregnant women also showed that 20 weeks of yoga intervention significantly reduced the cortisol hormone and improved the IgA level during pregnancy, which not only improved immunity and health but, with the long term in the intervention, also improved the birth outcome36.

The IgG level of the participants significantly (p < 0.01) decreased (-0.80 ± 1.04 g/l) after the yoga intervention. The effect size (cohen’s d = 0.771) shows the moderate effect of yoga on the IgG. The Reduction in IgG should be interpreted cautiously as every value remained in the normal range. IgG level is part of long-term immune memory; this result can be interpreted as the short-term yoga intervention may not impact long-term immune memory. The observed finding of IgG might not represent to clinical significance of weakening of immune protection. The IgM level of the participants in the current study shows a significant (p = 0.001) increase after the yoga intervention; however, a very small effect size (cohen’s d = 0.002) demonstrates that this change may show low clinical or practical relevance despite a significant increase. This result can be supported by the systematic review which states that no significant effect has been shown by the yoga intervention on IgM and IgG antibody37. However, there is a need to have further investigation on long-term yoga intervention on IgG and IgM levels for a better understanding.

Metabolic parameter

The results of the current study showed varied results on the effect of 10 weeks of yoga intervention on metabolic parameters. HbA1C and HbA1C_IFCC levels show a increase but not significantly (p = 0.360 and p = 0.293) after the yoga intervention. However, the very small negative effect size (cohen’s d -0.157 and d -0.180) can be interpreted as the practical impact of short-term yoga intervention having minimum impact on glycaemic control in the study population. In contrast, findings from the study conducted on the T2DM patient with three-month yoga intervention practice twice a week show a significant improvement in the glycaemic outcome with a significant decrease in HbA1C level38. This variation in findings highlights the potential influence of frequency as well as duration of yoga intervention on the impact of metabolic health. Additionally, the sociodemographic characteristics of the participant with baseline glycaemic status may also impact the findings. There was no significant increase in the value of FBG after the yoga intervention, with a small to moderate effect size (r = 0.278) between the FBG level and yoga intervention, which indicates that the intervention did not strongly influence FBG levels in these medical students. On the other hand, evidence shows that there was a significant reduction in the FBG level after the yoga intervention39,40,41,42. However, the small to moderate effect size shown in the current study concluded that there is an association between yoga and FBG levels. However, the short duration of the intervention, post-sampling in the exam period, may have influenced the non-significant changes in the current study. In terms of lipid profile, the current study shows the varied effects of 10 weeks of yoga intervention on the lipid profile of the participants. The level of cholesterol and triglycerides decreased after the intervention. However, this decrease was not statistically significant (p = 0.0554 and p = 0.298). The positive effect size (cohen’s d 0.101) indicates the potential benefit of yoga intervention to improve cholesterol levels. There was a small negative effect size (r = -0.176) that shows the practical implication of this finding that short-term yoga intervention may not produce reliable changes in triglyceride levels in this population. These results can be supported by the previous literature, which showed that long-term yoga intervention showed a pronounced improvement in cholesterol levels and triglycerides. However, the consistency and duration of practice with participant baseline character may also influence the findings27,43,44. Participants’ LDL levels did not significantly increase p = 0.14. The negative effect size (d -0.251) suggests that although there is a change in LDL level after the intervention, this change does not clinically meaningful impact. The level of HDL significantly increases after the yoga intervention (p = 0.005) with a negative effect size (d = -0.474). This can be interpreted as a moderate improvement in HDL level through yoga intervention. These noteworthy findings show the positive shift of lipid metabolism among participants through yoga intervention since the elevated HDL level is also associated with reducing the risk of cardiovascular disease45. The level of non-HDL decreased (p = 0.214) with a small effect size (d = 0.214) after the yoga intervention in the current findings. This small effect size shows the potential influence of long-term yoga intervention on lipid metabolism. The level of non-HDL slightly decreased but not significantly with a small effect size, which indicates the potential for future research to explore the clinical relevance of the effect of yoga on the non-HDL level; however, further study is needed to confirm these results with long-term effects. These positive finding by a current study on lipid metabolism is supported by meta-analysis46, which states that yoga has a potential yet positive impact on lipid profile, HbA1c, and blood pressure; it plays a crucial role in contributing to the primary prevention of cardiovascular disease. However, there was no significant change found in LDL and non-HDL levels may reduce the potential benefits of an increase in HDL levels on overall cardiovascular risk in medical students. Given the short duration of intervention and post-data collection during the exam period, we cannot assess the long-term effect of the current intervention on lipid profile. The improvement in metabolic markers in our study is supported by previous research, where it is demonstrated the positive effect of regular exercise on metabolic parameters47. Additionally, studies demonstrate that regular exercise has significant benefits for well-being and mood48. However current study findings only focus on metabolic and immune markers.

Medical students are more at risk of developing habits that increase the incidence of chronic diseases such as diabetes, cardiovascular disease etc., due to high levels of stress49. One of these unhealthy habits is a high level of sedentary behavior among medical students28 As mentioned, the post-sampling was collected during the exam period, this time is often associated with high sedentary behaviors due to high stress; this unexpected finding of some lipid parameters, IgG and IgM level after yoga intervention suggests that the other factors, for example, academic stress, lack of physical activity may counteract the effect of yoga intervention due to high-stress periods.

This study’s interpretation necessitates acknowledging several methodological limitations. The use of convenience sampling without an a priori power analysis resulted in a small sample size (n = 35), which limits statistical power and the generalizability of findings. While multiple comparisons were not adjusted using Bonferroni correction due to concerns about Type II errors in the exploratory context, this increases the risk of Type I errors, though effect sizes were considered for practical significance. Critically, the single-group, pre-post design lacks a control group, making it difficult to isolate the intervention’s effects from potential confounders like external physical activity, diet, sleep patterns, or natural variations, particularly as post-data collection occurred during a high-stress exam period known to affect physiological outcomes. Furthermore, the absence of validated psychological instruments complicates the direct assessment of mental health changes. The finding from the systematic review reported a positive effect of yoga on decreasing depressive symptoms among the population with mental disorders50. This study reported a dose-response relationship between the frequency of yoga intervention per week and improvement in depressive symptoms50. This gap should be addressed in future studies by including the mental health outcome data collected before and after the yoga intervention among medical students, Many studies support that yoga intervention can decrease the level of stress and anxiety among students and improve their emotional well-being18,23,51,52,53,54,55. Collectively, these factors, especially the lack of controls and potential confounding from the exam period timing, significantly impact the study’s internal validity and weaken causal attributions. It is suggested to interpret the result with caution by considering above mentioned gaps.

Methodology

The current study is an exploratory, pre-post-test study carried out in the framework of a pre-post-test yoga intervention at the University of Pécs, Hungary. It analyses the effect of yoga intervention on immune, metabolic, and psychological parameters among medical students.

Sampling

As noted above, the research population included medical students and was recruited through a convenient sample at the University of Pécs, Hungary, between 15 February and 15 May 2023. Based on the time-limited nature of the recruitment procedure, we did not conduct a power analysis for a predetermining sample size. The participants were encouraged to participate in the research study, the final sample size was determined by the number of students who volunteered to participate and later we obtained their written and verbal consent. Both male and female students from various years of study from the faculty of medicine participated. Additionally, to ensure the well-being and safety of all the students while participating in the intervention, certain inclusion and exclusion criteria were implemented. Inclusion Criteria- Students presently enrolled in the faculty of medicine at the University of Pecs could participate in the current study. Exclusion Criteria—Participants with certain health conditions, such as chronic pain, recent injuries, congenital skeletal abnormalities, chronic pain, musculoskeletal disorders, or significant arthritis, were considered for exclusion from the study. However, no participants were excluded; all the individuals who participated in the current study met the inclusion criteria. The included participants had no prior experience with yoga. Importantly, there were two dropouts among research participants during the intervention due to their transfer to another university. The information and data of dropouts were considered during the analyses of overall study findings to ensure that the dropouts did not affect the result, thus considering the reliability of the findings.

Intervention

The 10-week yoga intervention was conducted from September to December 2022, with weekly 90-minute yoga sessions. Each session followed a structured format with different activities outlined in Fig. 1. The “GSY Goodbye Stress with Yoga Protocol"18 was developed collaboratively by a certified yoga trainer, a medical researcher, and experienced yogis from India. Each intervention part was followed by 3 min of Corpse Pose (Shavasana). Participants were asked to avoid eating for two hours before the session. The sessions were held in the University of Pecs in the Faculty of Science gym room, thoroughly cleaned and prepared beforehand. Researchers provided sanitized yoga mats, with each participant using the same mat for every session. A certified yoga instructor with 7 years of experience holding certification from Swami Vivekananda International Youth & Yog Research Council (INDIA) led the sessions.

Fig. 1
figure 1

Graphical abstract.

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Population

Among the total participants, 81.1% were females and 18.9% were males in the current study. All medical students who registered with their interest in the physical education course named “Indian Yoga” were encouraged to participate in current research. Out of 75 registered students, 37 students participated in the current research with a mean age of 21.84 ± 2.67 years and a BMI of 22.56 ± 3.85 kg/m2. Before participation, all students received thorough instruction and details of the study procedure and purpose.

Reported outcome

We have used the immune parameters, which are IgA, IgG, and IgM, as the primary outcome, as chronic stress results in a decrease in the level of Immunoglobulin, which leads to a reduction in the individual’s immunity56. The secondary outcome measures were glucose, lactate, HbA1c, HbA1c_IFCC, cholesterol, non-HDL, HDL, LDL, and triglycerides.

Assessment of blood parameters

Fasting venous blood samples were collected from participants in the morning (7:00 AM to 8:00 AM); samples were drawn in suitable vacutainers; tubes containing potassium ethylenediaminetetraacetic acid (K-EDTA) were used to test hemoglobin A1c parameters. Tubes containing sodium-fluoride (NaF) were used for plasma glucose and lactate analysis, while native tubes were used to obtain serum in support of the routine laboratory blood tests. All samples were transferred to the laboratory within one hour, where plasma and serum were separated using centrifugation (15 min, room temperature, 1500 g). Plasma hemoglobin A1c levels were measured on a Tosoh G11 (Tosoh Bioscience, Tokyo, Japan) ion-exchange HPLC Analyzer, serum parameters including glucose, lactate, cholesterol, HDL, LDL, triglyceride, were measured using the Cobas 8000 Modular Analyzer (Roche Diagnostics, GmbH, Mannheim, Germany) while immunoglobulin levels were measured on Dade Behring BNII Nephelometer System (Siemens, Marburg, Germany) in strict accordance to the manufacturer’s recommended guidance. Importantly, Laboratory analysts were blinded to the personal identity of the participants, and all the samples before the analyses were coded.

Ethical declaration

All included participants provided their informed consent before any study-related procedure by signature on the consent form, which was explained verbally to each participant. The investigation of the current study conforms to the principles outlined in the Declaration of Helsinki. The National Research Ethics Committee reviewed and approved the study as the Review Board Record number 26914-5/2021/EÜIG National Public Health Center, Hungary. This current study was registered on the ClinicalTrials.gov platform (NCT06661603). The manuscript for this exploratory, single-group trial follows established clinical reporting guidelines, including a detailed discussion of its limitations to ensure methodological rigor and reproducibility.

Statistical analyses

The distribution of data was tested using the Shapiro-Wilk test. Descriptive analyses were conducted to summarise the demographic factors of participants. Paired sample T-tests were used for the normally distributed variables to compare the pre-and post-intervention mean and standard deviation. The effect size of these variables was calculated using Cohen’s d test. The effect size value was interpreted as Cohen’s d (small 0.2, medium 0.5, and large 0.8) to assess the magnitude of the intervention on the reported outcome57,58. For not normally distributed variables, mean and standard deviation were compared for pre- and post-intervention variables using the Wilcoxon signed ranked test. These variables’ effect sizes r were calculated using the formula r = z/√N ​, where z is the test statistic from the Wilcoxon Signed-Rank Test59. In this case, the interpretation of effect size value r is as (small 0.1, medium 0.3, and large 0.5)57. The significant level considered in each case was p < 0.05, all statistical analyses were performed using SPSS 26.0 software (SPSS Inc., Chicago, IL, USA). As per the exploratory nature of the current study and the small sample size, we did not apply a Bonferroni correction, we focused on prioritizing the detection of potential changes in outcome variables while acknowledging the increased risk of Type I errors. Statisticians who conducted the analyses were blinded to the personal identity of the participants, and all the samples before the analyses were de-identified and coded.

Conclusion

This exploratory study provides preliminary evidence shows the significant impact of 10 weeks of yoga intervention on immune and metabolic among medical students. Regular yoga practice for 10 weeks improved medical IgA level, blood glucose control, and favorable lipid parameters. The current finding underscores the potential of yoga intervention can positively influence certain aspects of medical student’s physiological health.

Future recommendation

Future studies should focus on the higher frequency of yoga intervention per week and its long-term impact on the clinical outcomes including mental health outcome of medical students. There is evidence that states that the frequency of yoga can improve the effect of yoga on health outcomes60. Exploring frequent yoga practice with long-term yoga practice could provide deeper knowledge of the sustained yoga effect on medical students’ immune, metabolic, and psychological health. Additionally, a well-structured randomized control trial is needed to reduce the bias and better understand the effect of yoga on different parameters, particularly in high-stress situations.