The goal of the clinical trial is to understand the effect of two resistance training protocols employing different loading intensities (% of 1 repetition maximum; 1-RM), but with standardized effort intensity (2 repetitions in reserve; RIR) on post-exercise and ambulatory blood pressure in aging females.
The main questions it aims to answer are:
* to examine the acute effects of low (50% 1-RM) and high (80% 1-RM) load intensity resistance exercise with a standardized high effort intensity on post-exercise hypotension and ambulatory blood pressure responses in aging females; * deepen the understanding of the mechanisms underlying acute reductions in blood pressure in response to resistance exercise performed at different load intensities. To this end, autonomic activity will be estimated alongside the measurement of central arterial compliance (i.e., carotid artery), and serum biomarkers of endothelial function; * document the affective valence and enjoyment associated with low (50% 1-RM) and high (80% 1-RM) load intensity resistance exercise when performed at a high perceived effort.
Researchers will compare the effect of: 1) a low load (LL-RE) intensity protocol consisting of 3 sets of each exercise at 50% 1-RM, performed until reaching a hard perceived effort intensity (i.e., RIR-2); 2) high load (HL-RE) intensity protocol consisting of 3 sets of each exercise at 80% of 1-RM, performed until reaching a hard perceived effort intensity (i.e., RIR-2); 3) and a control condition (CON) consisting of a standardized non-fatiguing cognitive task.
Participants will participate in:
* A preliminary assessment visit; * Two familiarization visits to validate the exercise prescriptions; * Three experimental visits (CON, LL-RE, HL-RE).
aged 50 to 70 years;
absence of menstruation for 12 consecutive months;
normal-high resting blood pressure (120 ≤ Systolic ≤ 139 mmHg and 80 ≤ Diastolic ≤ 89 mmHg) or stage 1 hypertension (140 ≤ Systolic ≤ 159 mmHg or 90 < Diastolic ≤ 99 mmHg);
physically inactive (< 150 minutes of structured aerobic physical activity per week);
orthopedic limitations or other contraindications to resistance exercise;
scheduled surgery during the study;
unstable hypertension (≥ 160/100 mmHg);
diagnosis of type 2 diabetes;
Crossover
Condition LL-RE
Other interventionLL-RE condition will consist of a 5-minute warm-up (slow-paced walking) and the following exercises: leg press, chest press, leg curl, and seated row. Three sets will be performed for each exercise with a 3-minute rest period between sets/exercises. Each exercise will be executed through a full range of motion, with participants encouraged to follow a 2-sec eccentric phase (guided by a mobile app metronome and supervised by an exercise physiologist) and to perform the concentric phase as fast as possible. Participants will be informed to: stop the set when they perceive to have reached the RIR target. • LL-RE: The low load intensity protocol consists of 3 sets of each exercise at 50% 1-RM, performed until reaching a hard perceived effort intensity (i.e., RIR-2).
Control
Other interventionControl condition: During the control condition, participants will sit quietly in a room maintained at a temperature of 22-24°C to prevent any influence on blood pressure values, for 60 minutes. During this period, they will perform a standardized non-fatiguing cognitive task: watching Earth, a documentary following the migration paths of four animal families.
Condition HL-RE
Other interventionHL-RE condition will consist of a 5-minute warm-up (slow-paced walking) and the following exercises: leg press, chest press, leg curl, and seated row. Three sets will be performed for each exercise with a 3-minute rest period between sets/exercises. Each exercise will be executed through a full range of motion, with participants encouraged to follow a 2-sec eccentric phase (guided by a mobile app metronome and supervised by an exercise physiologist) and to perform the concentric phase as fast as possible. Participants will be informed to: stop the set when they perceive to have reached the RIR target. • HL-RE: The high load intensity protocol consists of 3 sets of each exercise at 80% of 1-RM, performed until reaching a hard perceived effort intensity (i.e., RIR-2).
Change in blood pressure post-exercise
Oscillometric blood pressure monitor
Change in ambulatory blood pressure
Ambulatory blood pressure monitor
Heart rate variability
Heart rate monitor
Carotid artery diameter as assessed by Cardiovascular Suite v4.6.1
Doppler ultrasound
Carotid artery distensibility as assessed by Cardiovascular Suite v4.6.1
Doppler ultrasound
Carotid artery blood flow velocity
Doppler ultrasound
Velocity loss in concentric contraction speed
Video camera
Hematocrit/hemoglobin concentration
Hemoglobin analyzer
Estimated daily energy expenditure
Accelerometer
Time spent in the different sedentary behaviors
Accelerometer
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