Exercise Pressor Reflex and Lifelong Training

Study Overview
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Brief Summary
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Cardiovascular diseases represent the first mortality cause in the world. Ageing is considered as the most prominent risk factor for this kind of diseases. Also, hypertension represents one of the modifiable risk factors. Blood pressure response to exercise is governed by three systems: central command, baroreflex, and a feedback mechanism originating in the skeletal muscle. An abnormal cardiovascular response to exercise facilitates the occurrence of cardiovascular events. The goal of the study is to characterize the cardiovascular response in lifelong trained individuals and explore the potential benefits of endurance and strength training on cardiovascular regulation to exercise onset.

Detailed Description
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Population ageing represents a problem both for health outcomes and for social dynamics in the social welfare states. Currently, the over 60 represents the fastest growing segment of the population. Despite a downward trend in the incidence of cardiovascular diseases, they remain the main culprits for what concern mortality rates in the world. Increasing age is considered the major risk factor for cardiovascular mortality. One of the main components of the cardiovascular response to exercise is dictated by the exercise pressor reflex originating in the exercising muscle and responding to metabolic and mechanical stimuli. Research indicates that at least 20% of the regulation of blood pressure could be ascribed to these cardiovascular reflexes. A dysfunctional reflex-mediated response increases the chances of cardiovascular events that may end up in severe consequences. Chronic exercise training is recognized to be an important tool to control blood pressure. The mechanisms through which exercise exerts its effect are multiple. Among these, an improvement of the neural control of the reflex originating in the muscle seems a likely contributor. However, at present, the effect of chronic exercise training on the EPR response in the elderly has not been elucidated. The aim of the study is to characterize the central and peripheral cardiovascular response in the lifelong endurance and strength trained elders population.

Official Title
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The Effects of Lifelong Endurance and Strength Training on the Central and Peripheral Cardiovascular Responses

Conditions
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Healthy Aging, Cardiovascular Risk Factor

Intervention / Treatment
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* Behavioral: Exercise History


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria General: Young: 18 - 30, males, non smokers Old Sedentary: 65 -75, males, non smokers Old Endurance Trained: 65 -75, males, non smokers Old Strength Trained: 65 - 75, males, non smokers Exercise history (different for each group): Young: ≤ 5 h/week Old Sedentary: ≤ 2h/week Old Endurance Trained: ≥ 5 h/week, ≥ 30 years of practice, ≥ 4 sessions/week Old Strength Trained: ≥ 5 h/week, ≥ 30 years of practice, ≥ 4 sessions/week Exclusion Criteria: History of cardiovascular events/diseases Respiratory, musculoskeletal, renal, and insulin-resistant diseases Hypercholesterolemia Use of beta-blockers BMI ≥ 30

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 75 Years

Sexes Eligible for Study
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Male

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Young<br>Healthy young subjects (age 18 - 30 ) | Behavioral: Exercise History<br>* The groups will be divided based on their exercise history<br>|
| Old Sedentary<br>Healthy and sedentary old subjects (age 65 - 75) | Behavioral: Exercise History<br>* The groups will be divided based on their exercise history<br>|
| Old Endurance Trained<br>Healthy old subjects ( age 65 - 75) who participated in endurance sports for ≥30 years, ≥5 hours per week and ≥4 sessions per week | Behavioral: Exercise History<br>* The groups will be divided based on their exercise history<br>|
| Old Strength Trained<br>Healthy old subjects ( age 65 - 75) who participated in resistance training/sports for ≥30 years, ≥5 hours per week and ≥4 sessions per week | Behavioral: Exercise History<br>* The groups will be divided based on their exercise history<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Mean Arterial Blood Pressure (MAP) | Difference in MAP between groups to post-exercise cuff occlusion | 1 week after recruitment of the subject - We will measure the changes from baseline to the steady state response ( average of 3rd minute) | 
| Heart Rate (HR) | Difference in heart rate between groups to passive leg movement (PLM) | 1 week after recruitment of the subject - We will measure the change from baseline to peak (peak response in HR due to PLM) | 
| Muscle Sympathetic Nerve Activity - Microneurography | Difference in muscle sympathetic nerve activity between groups to the different stimulations | 1 week after recruitment - We will measure the change from baseline to mean value (during stimulation) | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Muscle oxidative capacity in vivo / blood pressure response | Linear regression to check whether an abnormal blood pressure response is explained by the different muscle oxidative capacity measured by NIRS in vivo | 10 days after recruitment - Cross-sectional comparison at one time point only | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Exercise Pressor Reflex, Metaboreflex, Mechanoreflex, Lifelong exercise training