The goal of this clinical trial is to learn if the combination between transcutaneous electrical nerve stimulation (TENS) and isometric exercise (IE) can improve blood pressure in men and women between 50 to 60 years old suffered from resistant hypertension which is a type of hypertension where blood pressure remains above your target goal despite the use of three or more different classes of antihypertensive medications at their maximum tolerated doses. The main question to answer is:
Is there a significant effect on the combined use of TENS and IE on peripheral hemodynamic parameters in patients with resistant hypertension? Total sample will be 50 patients from both sexes
I will compare between two groups:
Experimental group (15 men, 10 women) will take: medication plus IE and TENS Control group (15 men, 10 women) will take: medication plus Conventional Physical Therapy Program
Age between 50 and 60 years. Both sexes were included Patients had been diagnosed with hypertension for at least 5 years.
Systolic blood pressure (SBP) ≥140 mmHg and/or diastolic blood pressure (DBP) ≥90 mmHg despite the use of three or more antihypertensive medications of different classes, including a diuretic,
or controlled blood pressure (<140/90 mmHg) while on four or more antihypertensive medications.
Greater than 102 cm for males.
Secondary hypertension due to identifiable causes (e.g., renal artery stenosis, primary aldosteronism, pheochromocytoma).
History of major cardiovascular events in the last 6 months (e.g., myocardial infarction, stroke, or heart failure exacerbation).
Severe musculoskeletal or neurological disorders that impair the ability to perform isometric exercise safely (e.g., recent joint replacement, severe osteoarthritis, stroke with residual motor deficit).
Parallel
Transcutaneous Electrical Nerve Stimulation
DeviceApplication of TENS Electrode placements: bilaterally over the Paraspinal muscles at the T1-T5 levels (upper thoracic region), targeting sympathetic outflow to the cardiovascular system. Frequency: 2-10 Hz (low frequency stimulation) Pulse duration: 200 microseconds Intensity: strong but comfortable tingling sensations, below motor threshold (typically between 10-20mA) Session duration: 30 minutes per session Session frequency: 3 times per week Total intervention duration: 8 weeks
Isometric Exercise
BehavioralDevice: Hand grip dynamometer. protocol: * 30% of the participants' maximal voluntary contraction (MVC). * Duration per trial: 2 minutes. * Number of trials per session: 4 repetitions * Rest interval between trials: 1 minute * Session frequency: 3 sessions per week * Total session duration: 14 minutes Per session: * 4 sets × 2 minutes = 8 minutes of active contraction * Rest between sets: 1 to 3 minutes (average 2 min × 3 rests = 6 minutes) * So total session time: average 14 minutes. • Total intervention duration: 8 weeks
Aerobic, Dynamic Resistance, stretch and Breathing Exercises and Lifestyle Modification Advices
Behavioral1. Aerobic exercise: moderate (brisk walking): 30 min, 5 times per week. 2. Engage in dynamic resistance exercise (weight training): 2 or more days non-consecutive. 3. Minimize sedentary behavior 4. Maintain healthy weight 5. Nutritional advice like: * Eat at least 5 portions of fruit and vegetables * Eat more lean protein e.g. Fish and nuts * Eat less salt \<5g or 1tsp * Eat 25-29 g of fiber * Limit alcohol * Drink 2-3 cups of coffee and/or tea (unsweetened) 6. Others: * Sleep: 7-9h/day * Reduce stress: practice meditation or yoga 30 min per day * Listen to music at least 25 min, 3 times per week * Stop smoking * Limit pollutions exposure * Use digital wearables/apps to track movement 7. Breathing exercise: Slow breathing at a rate of 6 breath/min for 10 minutes. 8. Stretching exercise: Static stretching exercise is mainly for large bulky muscles 30 sec stretch, 30 sec rest for 5 min
Pulse Pressure
Definition and Calculation: Pulse Pressure (PP) is the primary hemodynamic outcome, representing the pulsatile component of the blood pressure waveform. It is calculated as the difference between Systolic Blood Pressure (SBP) and Diastolic Blood Pressure (DBP): PP = SBP - DBP. Measurement Method: Measurements will be obtained via manual auscultation using a calibrated sphygmomanometer. SBP is identified at Korotkoff Phase I and DBP at Phase V. To ensure precision, three readings will be taken at 2-minute intervals after a 5-minute rest; the mean values will be used for the final PP calculation. Clinical Significance: In resistant hypertension, PP is a robust indicator of large-artery stiffness and cardiovascular risk. This study evaluates the effect of combined transcutaneous electrical stimulation and isometric exercise on reducing PP, signifying improved vascular compliance and reduced hemodynamic load. Unit of Measure: mmHg
Mean Arterial Blood Pressure
Description: The primary outcome is the change in Mean Arterial Pressure (MAP) from baseline to the end of the intervention. MAP represents the average arterial pressure during a cardiac cycle, serving as a critical indicator of hemodynamic load in patients with resistant hypertension. Measurement \& Calculation: MAP will be determined via the manual auscultatory method using a mercury and a stethoscope. Following a 10-minute quiet rest in a seated position, three readings will be taken from the non-dominant arm (2-minute intervals). SBP and DBP will be recorded at Korotkoff phases I and V. MAP will then be calculated using the formula: MAP = DBP + 1/3(SBP - DBP). Unit of Measure: mmHg
Systolic Blood Pressure (SBP)
Definition: Systolic Blood Pressure (SBP) is the primary measure of peripheral hemodynamics. SBP reflects the maximum pressure exerted against arterial walls during ventricular contraction, while DBP reflects the minimum pressure during ventricular relaxation. Measurement Protocol: Measurements will be performed via manual auscultation using a calibrated sphygmomanometer and a high-quality stethoscope. SBP will be recorded at the onset of Korotkoff Phase I (clear tapping). Participants will rest seated for 5 minutes prior to assessment. Three readings, separated by 2-minute intervals, will be averaged to determine the final values. Clinical Significance: In resistant hypertension, SBP is the gold-standard markers for evaluating the efficacy of the combined transcutaneous electrical stimulation and isometric exercise intervention in reducing systemic vascular resistance and cardiovascular load. Unit of Measurement: mmHg
Heart Rate
Definition: Heart Rate (HR), measured in beats per minute (BPM), serves as a primary indicator of autonomic nervous system activity and cardiovascular workload. In patients with resistant hypertension, it reflects the chronotropic response to the combined intervention. Measurement Method: HR will be measured using a Granzia Pulsox digital pulse oximeter. The device will be placed on the index finger of the participant's non-dominant hand. Following a 5-minute period of seated rest, the investigator will wait for a stable plethysmographic signal on the Granzia display before recording the value. To ensure reliability, three consecutive readings will be taken at 1-minute intervals, and the mean value will be used as the primary data point for analysis. Clinical Significance: A reduction in resting HR would indicate a successful modulation of sympathetic activity following the TENS and isometric exercise protocol.
Autonomic parameters: Heart Rate Variability
Definition: Heart Rate Variability (HRV) is the physiological variation in time intervals between consecutive heartbeats (RR intervals). It is a non-invasive marker of autonomic regulation; high HRV indicates parasympathetic dominance (relaxation), while low HRV is associated with sympathetic overactivity and increased cardiovascular risk in hypertensive patients. Measurement Method: HRV will be assessed using the Welltory application via smartphone photoplethysmography (PPG). Participants will place their index finger over the phone's camera and flash for a 2-minute "liquid" measurement. To ensure clinical-grade data, the app's 300-beat mode will be enabled to capture time-domain (e.g., SDNN, RMSSD) and frequency-domain (LF/HF ratio) metrics. Standardization: Measurements will be performed at baseline and post-intervention in a seated, quiet environment. The mean of two consecutive measurements with \>95% accuracy scores (as reported by Welltory) will be used for analysis.
Physiological parameters: Oxygen Saturation
Definition: Peripheral oxygen saturation ($SpO\_2$) measures the percentage of oxygen-saturated hemoglobin. In this trial, it serves as a safety and physiological marker during the combined TENS and isometric exercise intervention for resistant hypertension. Measurement Method: SpO\_2 will be measured using a Granzia digital pulse oximeter. The sensor will be applied to the index finger of the non-dominant hand. Following 5 minutes of seated rest, the investigator will record the value once a stable plethysmographic waveform is displayed on the Granzia screen. Three readings will be averaged to ensure data reliability. Clinical Significance: Monitoring SpO\_2 ensures that the pressor response during exercise does not compromise systemic oxygenation. Normal values (\> 95) indicate the intervention is well-tolerated without respiratory distress.
Functional parameter: QoL (SF-36)
Description: The Short Form-36 (SF-36) questionnaire is used to evaluate the physical and mental health status. It consists of 36 items covering eight health domains. Unit of Measure: Units on a scale Scale Range: The total score ranges from 0 to 100. Interpretation: Higher scores indicate better health-related quality of life, while lower scores indicate more disability or poorer health status.
Functional Capacity (modified Harvard step test)
Description: The Modified Harvard Step Test is used to measure cardiovascular fitness and aerobic capacity. The Fitness Index is calculated based on the duration of the test and the heart rate recovery after exercise. Unit of Measure: Units on a scale Scale Range: Fitness Index scores (typically range from \<55 "Poor" to \>90 "Excellent"). Interpretation: A higher Fitness Index score reflects better cardiovascular endurance and more
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Mohamed Mohamed Ali Morgan
Lead sponsor
Cairo University
Sponsor institution
