This study aims to explore the relationship between sarcopenia, fatigue, and orthostatic intolerance in older adults. It will be conducted among geriatric patients attending Ain Shams University Hospitals.

Participants aged 65 years and older will be divided into two groups: those with sarcopenia, diagnosed according to the European Working Group on Sarcopenia in Older People 2, and age- and sex-matched controls without sarcopenia. The study will compare levels of fatigue and the presence of orthostatic intolerance between the two groups.

The findings are expected to improve understanding of how sarcopenia is associated with fatigue and orthostatic symptoms in the elderly population, which may help guide better clinical assessment and management.

This case-control study aims to investigate the association between sarcopenia, fatigue, and orthostatic intolerance among older adults. The study will be conducted on geriatric patients attending Ain Shams University Hospitals outpatient clinics and inpatient services.

Participants aged 65 years and older will be recruited and categorized into two groups: patients diagnosed with sarcopenia according to the European Working Group on Sarcopenia in Older People 2 criteria, and age- and sex-matched controls without sarcopenia. Sampling will be performed using a simple random sampling technique.

All participants will undergo a comprehensive geriatric assessment, including detailed medical history taking (with emphasis on comorbidities, medication use, and history of falls) and thorough clinical examination. Functional status will be evaluated using Activities of Daily Living (ADL) and Instrumental Activities of Daily Living (IADL). Nutritional status will be assessed using the Mini Nutritional Assessment (MNA), while cognitive function and mood will be evaluated using the Arabic versions of the Mini-Addenbrooke's Cognitive Examination (Mini-ACE) and the Geriatric Depression Scale (GDS), respectively.

Sarcopenia assessment will be based on muscle strength, muscle mass, and physical performance. Muscle strength will be measured using handgrip dynamometry, muscle mass will be estimated using bioelectrical impedance analysis, and physical performance will be evaluated using the Timed Up and Go Test (TUGT) and SARC-F questionnaire.

Orthostatic intolerance will be assessed through both subjective and objective measures. Participants will be evaluated for symptoms such as dizziness, syncope or presyncope, visual disturbances, fatigue, palpitations, and exercise intolerance. Symptom severity will be quantified using the Orthostatic Hypotension Questionnaire (OHQ). In addition, orthostatic vital signs will be measured using an automated monitor, with heart rate and blood pressure recorded after a 20-minute supine rest and at 1, 3, 5, and 10 minutes following standing.

Fatigue will be assessed using the Arabic version of the Fatigue Severity Scale (FSS). Physical activity levels will be evaluated using the Incidental and Planned Exercise Questionnaire (weekly version).

Inclusion Criteria:

• Patients (males or females) aged 65 or above years old.
• Participants who are willing to participate in the study.

Exclusion Criteria:

• Patients who are not willing to participate in the study.
• patients with end organ damage (CHF NYHA III/IV), end-stage renal disease, Liver cell failure, respiratory failure.
• Patients with arrhythmia or using pacemakers
• patients diagnosed with parkinsonism, Diabetes mellitus, or peripheral neuropathy.
• Active infections or inflammatory conditions (e.g., sepsis, rheumatoid flare-up)
• Patient with acute stroke, Critically ill patients, Terminal illness, Bedridden or completely immobile patients,
• Medications Influencing Fatigue/OI: High-dose opioids, sedatives, or drugs causing significant orthostatic hypotension (e.g., alpha-blockers, diuretics without stable control)

elderly patients both males and females who are interviewed at AIN SHAMS UNIVERSITY HOSPITALS or at the hospital clinic.