The purpose of this study is to find out if regular handgrip exercise performed at home can improve blood pressure at rest and during exercise in patients with chronic kidney disease (CKD). This study is also intended to understand what causes an increase in blood pressure at rest and during exercise (i.e., increased adrenaline levels, or decreased ability of blood vessels to dilate). Patients with CKD will be recruited from primary care, Nephrology and other subspecialty Clinics throughout the Emory Healthcare System. Participants will attend 4 visits of 2-3 hours and 3 visits of 1-2 hours. The home exercise training will last for 8 weeks.
The goal of this study is to learn more about if exercising the grip strength at home can improve blood pressure control. Patients with Chronic Kidney Disease (CKD) have a much higher risk of cardiovascular problems than healthy people. Early results show that patients with CKD have issues controlling their blood pressure. The investigators think that this type of exercise, where you use a grip device to squeeze, might help improve health by lowering blood pressure. Even though the American Heart Association recommends this kind of exercise, not many people are using it. The study population will consist of 50 patients with CKD in stages III and IV. They will do the grip exercise three times a week at home, squeezing a grip device four times for 2 minutes with each hand. The research team will also check their flight-or-flight control and artery health to see how this exercise training might help. The investigators will collect some blood samples to understand what changes are happening in their bodies. Patients with CKD will attend 4 visits of 2-3 hours and 3 visits of 1-2 hours. The home exercise training will last for 8 weeks. Therefore, the approximate study duration is around 12 weeks. Patients with CKD will be recruited from primary care, Nephrology and other subspecialty Clinics throughout the Emory Healthcare System. No bank for specimens or data will be maintained. The informed consent process will occur in-person. This study will help to find new ways to improve CKD cardiovascular health.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
OTHER
Maximum voluntary contraction (MVC) will be assessed first in both hands using a hand dynamometer with a digital display (Handexer HFEH20); the participant squeezes the hand dynamometer as hard as they can for 3 to 5 attempts to obtain the MVC. The intervention is an 8- week training protocol that consists of handgrip exercises performed by the participant at home. Each cycle of sustained handgrip exercise consists of sustained squeezing of the hand dynamometer at 30% of MVC for 2 minutes (i.e. isometric) followed by 1 minute of rest.
Each cycle of sustained handgrip exercise consists of sustained squeezing of the hand dynamometer at 3 - 5% of MVC rather than 30%.
Emory University
Atlanta, Georgia, United States
Change in resting blood pressure (BP)
Resting BP will be recorded
Time frame: Baseline, 8-weeks post-intervention
Change in standard deviation BP variability
Resting beat-to-beat BP will be continuously measured for 10 min. Then, the standard deviation, and BP variability in mmHg will be calculated
Time frame: Baseline, 8-weeks post-intervention
Change in average real BP variability
Resting beat-to-beat BP will be continuously measured for 10 min. Then, the average variability in mmHg will be calculated.
Time frame: Baseline, 8-weeks post-intervention
Change in the coefficient of variation of BP variability
Resting beat-to-beat BP will be continuously measured for 10 min. Then, the coefficient of variation of BP variability in % will be calculated.
Time frame: Baseline, 8-weeks post-intervention
Change in Brachial artery flow-mediated dilation (FMD)
FMD of the brachial artery will be measured using doppler ultrasound. The image of the brachial artery will be obtained in the distal third of the arm (2-10 cm above the antecubital fossa) using a multi-frequency linear probe attached to a high-resolution Doppler US.
Time frame: Baseline, 8-weeks post-intervention
Change in Vascular stiffness
Vascular stiffness will be quantified as pulse wave velocity using applanation tonometry with a high-fidelity micromanometer. It will be reported in meters per second (m/s).
Time frame: Baseline, 8-weeks post-intervention
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Masking
SINGLE
Enrollment
50
Change in 24-hour ambulatory BP monitoring (ABPM)
ABPM will be performed with SpaceLab "On Trak" ambulatory BP monitors. Upper arm readings will be taken for at least 24 hours. BP measurements will be made every 20 minutes from 7 AM to 11 PM (daytime period) and every 30 minutes from 11 PM to 7 AM (nighttime period). Average BP in mmHg will be recorded.
Time frame: Baseline, 8-weeks post-intervention
Change in resting muscle sympathetic nerve activity (MSNA)
The tungsten microelectrode will be inserted under ultrasound guidance into the peroneal nerve to measure MSNA. Nerve signals are preamplified (gain 1000), amplified (gain 50-100), filtered (700-2000 Hz), rectified, and integrated (time constant 0.1 sec) to obtain a mean voltage display of sympathetic nerve activity that is recorded. Muscle sympathetic bursts are identified by visual inspection and expressed as burst frequency (bursts min).
Time frame: Baseline, 8-weeks post-intervention
Change in BP reactivity to cold pressor test (CPT)
The CPT will be performed by submerging the participant's hand in cold water (\~0-4°C) up to the wrist for 1 minute. BP reactivity to the CPT in mmHg will be recorded.
Time frame: Baseline, 8-weeks post-intervention
Change in heart rate reactivity to cold pressor test (CPT)
Heart rate reactivity to the CPT in beats per minute will be recorded.
Time frame: Baseline, 8-weeks post-intervention
Change in MSNA reactivity to cold pressor test (CPT)
The MSNA reactivity in bursts/min will be recorded during the CPT using the tungsten microelectrode.
Time frame: Baseline, 8-weeks post-intervention
Change in BP reactivity to handgrip exercise
BP reactivity (in mmHg) to handgrip exercise, an isometric hand contraction at 30% of their maximal voluntary contraction (MVC) for 3 minutes followed by inflation of the BP cuff in their upper arm for another 3 minutes, will be recorded.
Time frame: Baseline, 8-weeks post-intervention
Change in heart rate reactivity to handgrip exercise
Heart rate reactivity in beats per minute will be recorded during the handgrip exercise.
Time frame: Baseline, 8-weeks post-intervention
Change in MSNA reactivity to handgrip exercise
The MSNA reactivity in bursts/min will be recorded during the handgrip exercise.
Time frame: Baseline, 8-weeks post-intervention
Change in skeletal muscle oxygenation during handgrip exercise
Skeletal muscle oxygenation will be calculated during handgrip exercise using Near-infrared spectroscopy (NIRS). NIRS will measure changes in oxyhemoglobin (oxygenated hemoglobin), deoxyhemoglobin (deoxygenated hemoglobin), and total hemoglobin. Percentage of oxyhemoglobin will be reported.
Time frame: Baseline, 8-weeks post-intervention
Change in interstitial muscle pH during handgrip exercise
Change in interstitial muscle pH during handgrip exercise will be assessed using NIRS.
Time frame: Baseline, 8-weeks post-intervention
Change in cardiac baroreflex sensitivity
The spontaneous cardiac baroreflex sensitivity expressed in milliseconds per mmHg (ms/mmHg) will be calculated at baseline, and at the end of the 8-week trial period.
Time frame: Baseline, 8-weeks post-intervention
Change in sympathetic baroreflex sensitivity
The spontaneous sympathetic baroreflex sensitivity expressed in bursts per 100 heartbeats per mmHg will be calculated at baseline, and at the end of the 8-week trial period.
Time frame: Baseline, 8-weeks post-intervention
Change in Inflammatory markers: C-Reactive Protein (CRP)
Blood will be collected at baseline, and at the end of the 8-week trial period to measure CRP.
Time frame: Baseline, 8-weeks post-intervention
Change in Inflammatory markers: Interleukin-6 (IL-6)
Blood will be collected at baseline, and at the end of the 8-week trial period to measure IL-6.
Time frame: Baseline, 8-weeks post-intervention
Change in Inflammatory markers: endothelin
Blood will be collected at baseline, and at the end of the 8-week trial period to measure endothelin.
Time frame: Baseline, 8-weeks post-intervention
Change in Inflammatory markers: asymmetric dimethyl arginine (ADMA)
Blood will be collected at baseline, and at the end of the 8-week trial period to measure ADMA.
Time frame: Baseline, 8-weeks post-intervention
Change in Inflammatory markers: phospholipase A2 (PLA-2)
Blood will be collected at baseline, and at the end of the 8-week trial period to measure PLA-2.
Time frame: Baseline, 8-weeks post-intervention