Hemodialysis (HD) patients have decreased physical functioning, diminished muscle mass and altered muscle quality thus the increased mortality rate compared to their age-matched population. Risk factors include their sedentary lifestyle and altered nutritional status [1]; the sedentary lifestyle or the lack of exercise is known to be a risk factor for cardiovascular complications [2] and contributes to worsen protein energy wasting (PEW), which is described as the loss of body protein mass and fuel reserves [1]. Therefore the health of the HD patients and consequently their quality of life (QOL) is deteriorated.

Studies have shown that aerobic exercise during HD improves aerobic capacity, blood pressure, heart rate, muscular strength, dialysis efficacy and quality of life; however, such studies were not done on the United Arab Emirates (UAE) HD patients and there is no protocol for implementing exercise in the UAE HD units [3-4]

Hypothesis: Intradialytic aerobic exercise will result in significantly improved clinical, cardio-metabolic and quality of life outcomes and reduced cost of care.

Primary objective of the study:

- To investigate whether the intradialytic exercise (IDE) within the routine practice of hemodialysis in the UAE will improve adequacy of dialysis.

Secondary objectives of the study:

• To study the effect of clinical and cardio-metabolic outcomes of the HD patients.
• Explore whether the trial would improve the cost effectiveness of this patient population's health care
• Define the nature of the IDE programs (intensity, duration, modality), and feasibility of its application in routine setting.

Importance of this research:

• Pioneering research in the Middle East and Gulf Cooperation Council (GCC) countries where the effect of intradialytic exercise will be studied for the first time on Arab population.
• It will contribute in identifying the exact strategies to integrate within the hemodialysis unit to improve clinical and cardio-metabolic outcomes, quality of life and healthcare cost.

Usefulness of this research to the UAE

• It will improve the health care cost and reduce cost wastage in the UAE (lean management).
• It will put UAE on the pedestal in front of other countries in integrating innovative methods for a better care of hemodialysis patients.

Each patient will be asked to follow an Intradialytic aerobic low intensity exercise program of 45 minutes per each HD session throughout the 6-month study duration. The exercise will be tailored to each HD patient's ability (measured by VO2Max), supervised by the hospital physiotherapist and the research team. Continuous support and encouragement to the patients will be provided to assure they complete the 45 minutes of exercise on each HD session. Additionally, patients will be educated on the health benefits of exercise and how to integrate safe exercise into their daily life (by the research assistants).

Research assistants will be trained by the principal investigator (PI) on the study instruments and data collection methods. These assistants will administer 4 questionnaires (5 minutes each) for each HD patient separately and will collect data from the medical chart of each patient. The assessment will take place during the HD session.

The research assistants will also collect from the patient's file blood test results on a monthly basis (relevant to the study mentioned in table1); additional needed parameters will be analysed from the same blood sample that the hospital already collect for the patients monitoring, and will be analysed by the hospital for a fee from the research fund. For the β-aminoisobutyric acid (BAIBA) tests - cardiometabolic marker, 5 ML of the blood sample from each patient will be transported to a specialized lab for analysis.

All of the parameters, except the demographics (collected only at t0), will be collected and monitored at 3 time points: Baseline (t0), post-intervention (t1) and follow up (t2).

Assessment tools include

• Demographics: Height - Weight - Age - Social and Work status - Comorbidities - Education level
• Biochemical markers: C-reactive protein, Urea reduction ration, Phosphorus (P), BAIBA, Vitamin D3, Parathyroid Hormone, Calcium and Phosphorus Product
• Number of hospitalization days and emergency HD sessions
• Exercise Behavior questionnaire consists of 7 questions to assess the activity level of the patient before implementing the program. It will reflect the patient's activity level and importance.
• Barriers to physical activity questionnaire [5], which includes questions related to different categories of disease- and patient- specific barriers to physical activity (psychological, physical, and economical barriers) in addition to the lack of time factor.
• Malnutrition Inflammation Score (MIS) [6]: This is a comprehensive scoring system with significant associations with prospective hospitalization and mortality as well as measures of nutrition, inflammation, and anemia in HD. MIS has 10 components, each with four levels of severity from 0 (normal) to 3 (severely abnormal). The sum of all 10 MIS components ranges from 0 (normal) to 30 (severely abnormal); a higher score reflects more severe degree of malnutrition and inflammation. The scoring sheet consists of four sections.
• Quality of life (QOL) measured using the EuroQOL -5 health questionnaire [7]. It assesses 5 health concepts: mobility, self-care, usual activities (work, study, housework, and family or leisure activities), pain / discomfort, and anxiety / depression. Patients have 5 choices for each question to choose from to describe their health today. In addition, patients have to indicate on a scale marked from 0-100 their opinion about how good or bad their health state is today.
• Exercise effort test: Heart rate monitoring to assess the level of exercise performed [8]
• Exercise Fitness Level: measure using the Borg Scale of perceived Exertion [9]

All questionnaires that are originally not Arabic, will be translated to Arabic (local language), prior to study by 2 translators whose first language is Arabic. Next step, each questionnaire will be translated back to English by a dietitian whose first language is English and who also knows Arabic. All questionnaires will be validated by running them on 10 patients and accordingly modifying their feasibility to the Emirates HD patient's culture, language level and comprehension status.

The physiotherapist and the research assistants will be responsible for training the patients on the exercise program and recording the intensity, duration, and modality of the exercise for each patient as well as patient's complaints and reasons for drop out, if any. The intervention will be given within the HD session: no extra time required beyond the time of HD. During the intervention, patient will be at all times under direct supervision of the physiotherapist and medical team; in case of any discomfort, the intervention will be immediately stopped.

Sample size was chosen based on convenient sampling. Patients of the HD unit who received clearance from the medical team, met the inclusion criteria and consented, were included in the study.

Data will be analyzed through Scientific Package for Social Sciences version 18. Descriptive statistics will be used to analyze the data. Correlations will be conducted through ANOVA. Effect of the study will be analyzed by paired t test on continuous data and Chi-square on categorical data

Inclusion Criteria:

• HD patients from the selected HD units in the UAE on HD 3 times a week
• Stable on HD (free of life -threatening acute or chronic disease, with a life expectancy of > 6 months)
• ≥ 3 months on HD
• The gender being irrespective (age ≥ 18)
• Not practicing any physical activity
• With no recent hospitalization (in the last 3 months for ACUTE condition)
• At their full capacity of cognitive, psychiatric and physical ability for self-care and communication
• Capable to communicate either verbally or through writing
• Fully aware of the proposed protocol of the study, and able to provide a consent form.
• All selected patients should have received clearance from their nephrologist and cardiologist that they are eligible to start an exercise program

Exclusion Criteria:

• Patients not meeting the inclusion criteria listed above
• Patients not able to perform the exercise program
• Patients who did not receive the clearance of the attending nephrologist of the unit to participate in the study