Ischemic Preconditioning in Resistance Exercise in Older Women

Aging is associated with significant cardiovascular alterations, including increased arterial stiffness, impaired endothelial function, and elevated cardiac workload during and after physical exercise. In older women, these changes are exacerbated by postmenopausal hormonal decline, increasing vulnerability to cardiovascular stress.

Resistance exercise is recommended to improve strength, functional capacity, and overall health in older adults. However, it may induce acute increases in blood pressure and myocardial workload, particularly in individuals with reduced vascular compliance and impaired autonomic regulation. These responses may persist into the recovery period, increasing cardiovascular risk.

Ischemic preconditioning (IPC) is a non-pharmacological intervention that involves repeated cycles of vascular occlusion and reperfusion. This procedure can promote vascular adaptations, including increased nitric oxide bioavailability, improved endothelial function, and reduced peripheral vascular resistance. These mechanisms may contribute to attenuating hemodynamic stress during and after exercise.

Although IPC has shown promising results in young adults and clinical populations, there is limited evidence regarding its effects on hemodynamic responses following resistance exercise in older women.

This study is designed as a randomized, single-blind, crossover clinical trial including 30 physically independent women aged 60 years or older. Participants will complete two experimental conditions in randomized order: ischemic preconditioning (IPC) and a sham condition (SHAM).

The IPC protocol consists of three cycles of 3 minutes of arterial occlusion at a pressure 50 mmHg above systolic blood pressure, interspersed with 3 minutes of reperfusion. The sham condition consists of the same procedure with a fixed low pressure (20 mmHg), insufficient to induce arterial occlusion.

After each intervention, participants will perform a standardized resistance exercise session composed of four exercises: horizontal row, bench press, leg extension, and 45-degree leg press. The intensity will be set at 80% of 10-repetition maximum, with three sets of 10 repetitions per exercise and standardized rest intervals.

Hemodynamic variables will be assessed at rest, after the intervention, during exercise, and during recovery. The primary outcome is cardiac workload, assessed by the rate-pressure product, measured 20 minutes after exercise.

Secondary outcomes include systolic, diastolic, and mean arterial blood pressure, heart rate, and heart rate recovery at 60 seconds. Perceptual variables will be used to ensure similar baseline conditions between sessions.

Statistical analysis will be performed using linear mixed models, including condition, period, and sequence as fixed effects, with baseline values as covariates and random intercepts for participants.

Inclusion criteria

• Female participants aged 60 years or older
• Physically independent
• Engaged in regular physical activity (at least two sessions per week for the last three months)
• Cleared for exercise participation by a cardiologist following clinical evaluation
• Able to safely perform resistance exercise
• Provided written informed consent

Exclusion criteria

• - History of cardiovascular events such as myocardial infarction or stroke
• Uncontrolled hypertension (≥160/105 mmHg)
• Diabetes mellitus
• Current smoking or alcohol abuse
• Musculoskeletal limitations that impair exercise performance
• Cognitive or communication impairments that interfere with understanding instructions