Acute Effects of Handgrip on Blood Pressure in Hypertensive Adults

Experimental: Handgrip exercise (morning)

The handgrip exercise session will be executed with four series (two in each arm) of two minutes of isometric contraction at 30% of maximum voluntary contraction, with a one-minute interval between series in the morning.

Sonstiges: Acute effects of handgrip exercise

The participants will be randomized into three sessions, handgrip exercise in the morning, handgrip exercise in the afternoon, and control performed in the morning to analyze the acute effects of handgrip exercise on blood pressure and vascular function at different times of the day. After the morning sessions, ambulatory blood pressure will also be measured for 24 hours.

Kein Eingriff: Control

In the control session, the participants will remain at rest for the same period of time as in the handgrip exercise protocol.

Experimental: Handgrip exercise (afternoon)

The handgrip exercise session will be executed with four series (two in each arm) of two minutes of isometric contraction at 30% of maximum voluntary contraction, with a one-minute interval between series in the afternoon.

Sonstiges: Acute effects of handgrip exercise

The participants will be randomized into three sessions, handgrip exercise in the morning, handgrip exercise in the afternoon, and control performed in the morning to analyze the acute effects of handgrip exercise on blood pressure and vascular function at different times of the day. After the morning sessions, ambulatory blood pressure will also be measured for 24 hours.

Change in Ambulatory Blood Pressure

The ambulatory blood pressure will be collected for a 24-hour period using an automatic device (Dyna-MAPA, Cardios, Brazil). The device, duly calibrated, will be connected to a cuff, in the arm of preference, for the evaluation measurements. The device will be programmed to take measurements throughout the day at 15-minute intervals and during the night every 30 minutes (between 11:00 p.m. and 7:00 a.m.). All subjects will be given forms to record possible eventualities during the use of the device.

Change of clinical blood pressure from pre to post session

For the measurement of clinical blood pressure, the Omron HEM 742 automatic equipment will be used. Initially, the participant will remain for 10 minutes in dorsal decubitus and then a cuff appropriate for the circumference of the participant's arm will be placed. On the right arm, consecutive measurements will be taken, one minute apart, until a difference of less than 4 mmHg between two measurements is reached. For analysis purposes, the average of the last two measurements will be used, as recommended by the 7th Brazilian Guideline on Hypertension.

Change in vascular function from pre to post session

The vascular function will be assessed using the flow-mediated dilation (FMD) technique using the LOGIQ S7 Expert ultrasound device (GE Healthcare), following the recommendations of Thijssen et al. (2019). For FMD collection, the baseline diameter of the artery will be assessed before cuff inflation for a period of at least 30 seconds. The cuff will then be inflated to 50 mmHg above the individual's systolic blood pressure for five minutes, and after this period, the cuff will be deflated and diameter measurement will be assessed for three minutes. The post-deflation diameter measurement will start 30 seconds before the cuff is released. Throughout the collection, continuous measurements of the brachial artery diameter (mm) using the Doppler function will be recorded for future analyses in percentage change.