Extended Abstract
Background and Purpose
Over the past decade, interest in vascular comorbidities among multiple sclerosis (MS) patients has increased. Recent studies link arterial stiffness to myelin damage and indicate that endothelial dysfunction is more prevalent in MS, accompanied by elevated serum endothelin-1 (ET-1) levels. This increase correlates with altered cerebral circulation time (CCT), cerebrovascular dysfunction, and a higher risk of ischaemic stroke. Many MS patients also exhibit impaired autonomic heart control, often characterised by reduced heart rate variability (HRV) and a shift towards increased sympathetic and decreased parasympathetic activity, which may contribute to fatigue, disability, stress responses, and elevated blood pressure. The complexity of vascular complications throughout MS progression and their impact on health outcomes warrant further investigation. Clinically, assessing vascular function beyond baseline blood pressure – such as arterial stiffness and endothelial function – may improve cardiovascular risk management in MS patients. Although vascular dysfunction precedes cardiovascular damage, understanding its role in MS and the potential of non-pharmacological interventions remains limited. Therefore, this study investigated the effect of a combined exercise training programme on endothelial dysfunction (endothelin-1) and its relationship with psychological and haemodynamic stress in women with MS.

Materials and Methods
Thirty women with MS were selected according to the modified McDonald criteria (2024) and neurologist approval. Using convenience sampling, they were randomly assigned to the exercise group (n = 15) or the control group (n = 15). Inclusion criteria were relapsing-remitting multiple sclerosis (RRMS), age 20–40 years, an EDSS score ≤ 5.5, and no active relapse in the previous 30 days. Exclusion criteria were other neurological or autoimmune diseases, pregnancy or lactation, use of immunosuppressive drugs, severe cognitive impairment, and medication changes during the study. The experimental group completed a combined exercise program for 12 weeks, three times per week, with sessions lasting at least 60 minutes. The program included aerobic exercises (40-60% maximum heart rate, RPE 11-13, increasing by 5% every three weeks), resistance training (starting with 3 sets of 8  reps, adding 1 set and 3 reps every three weeks), balance exercises (beginning with 4 movements and gradually increasing to 8), and breathing-stretching exercises (5-8 reps, adding one rep every three weeks).Before and after the intervention ET-1 levels were measured by ELISA using a ZellBio kit (Germany). Blood pressure and heart rate were recorded with an Omron M3 digital device. Anxiety was assessed using the Beck Anxiety Inventory (BAI), and motor function was evaluated with the Six-Point Stride Test (SSST). Data were analysed using ANCOVA and Pearson’s correlation coefficient, with significance set at p < 0.05.

Results
Based on the independent t-test results, no significant differences were found between the experimental and control groups in baseline characteristics, including age (37.25 ± 4.28 vs. 36.3 ± 3.75 years), weight (70.41 ± 11.65 vs. 73.58 ± 10.58 kg), and MS disease duration (7.75 ± 3.51 vs. 6.83 ± 3.21 years). Exercise training significantly increased motor performance and reduced ET-1 levels and anxiety in the experimental group compared to the control group (p < 0.05). At baseline, both groups experienced moderate (scores 22–35) to high anxiety levels (scores ≥36). In the intervention group, 54% had moderate anxiety and 46% had high anxiety, while in the control group, 64% had moderate and 36% had high anxiety. After the exercise intervention, 31% of the intervention group had low anxiety, 54% moderate, and 15% high anxiety. As shown in Table 2, the intervention group demonstrated a significant reduction in mean anxiety scores compared to controls (p = 0.001). Following the intervention, 57% of the control group still experienced moderate anxiety, and 43% had high anxiety. A significant positive correlation was found between reductions in anxiety and ET-1 levels (r = 0.754, p = 0.003). Despite significant decreases in systolic blood pressure (p = 0.001), diastolic blood pressure (p = 0.005), and heart rate (p = 0.001), there was no significant association between these variables and ET-1 levels (p>0.05). The exercise group showed significant improvements in motor function compared to controls. The combined exercise intervention was associated with a reduced time to complete the six-point step test relative to the control group (p = 0.002).

Conclusion
This study demonstrated that a course of combined exercises can reduce serum ET-1 levels. Although the exact mechanism by which combined exercises reduce ET-1 remains unclear, exercise generally modulates oxidative stress and inflammation, enhances nitric oxide bioavailability, and reduces sympathetic activity, thereby decreasing ET-1-mediated vasoconstriction. One benefit of the breathing exercises used in this intervention is increased vagal activity through a significant reduction of sympathetic activity. This process decreases baroreflex sensitivity, lowers total peripheral resistance, and ultimately reduces blood pressure and heart rate. Additionally, these exercises may alleviate anxiety by diminishing sympathetic activity. In the present study, anxiety reduction through combined exercise intervention was significantly correlated with decreased endothelin-1 in MS patients, consistent with similar research. However no significant correlation was found between blood pressure and ET-1. Predictive studies suggest that higher ET-1 levels may be a risk factor or marker for future hypertension and arterial stiffness may precede the development of hypertension in MS and contribute to disease progression and other comorbidities, such as atherosclerosis and cerebrovascular diseases.

Article Message
Overall, the findings of this study indicate that combined exercises, in addition to improving motor function, can favourably reduce serum ET-1 concentrations related to vascular function in patients with multiple sclerosis (MS). It appears that the reduction in endothelin-1 is due to decreased psychological anxiety rather than changes in blood pressure. These results provide a basis for designing and implementing targeted exercise programmes for patients with MS and similar conditions. Additionally, emphasising combined interventions to improve both motor and psychological aspects can be proposed as a new approach to enhancing the quality of life for this group of patients.
Ethical Considerations
This study complied with the guidelines of the Declaration of Helsinki and was registered with the clinical registry under the ethical code (IR.AZARUNIV.REC.1402.014)

Authors’ Contributions
Conceptualization: Azam Zarneshan
Data Collection: Azam Zarneshan, Yousef Saberi Banaem, Haniyeh Ghaffari
Data Analysis: Azam Zarneshan
Manuscript Writing: Azam Zarneshan
Review and Editing: Azam Zarneshan, Yousef Saberi Banaem, Haniyeh Ghaffari
Responsible for Funding: Azam Zarneshan, Haniyeh Ghaffari
Literature Review: Azam Zarneshan, Yousef Saberi Banaem
Project Manager: Azam Zarneshan

Conflict of Interest
The authors declare no conflict of interest concerning the publication of this article.

Acknowledgments
We sincerely thank all the valued patients who assisted us in this study.