This study will investigate the acute and chronic effects in hemodynamic and autonomic variables to high-intensity interval versus moderate-intensity continuous heated water-based exercise in older individuals with hypertension.

BACKGROUND: Population aging is an unprecedented worldwide reality, which results in a change of epidemiological profile and increased prevalence of age-related non-communicable chronic diseases (NCDs). Among age-related NCDs, systemic arterial hypertension (HPT) is the leading cause of mortality and disability worldwide and has increased prevalence, morbidity and mortality with advancing age. Increase in physical activity level through regular physical exercise is one of the main global goals for the prevention and treatment of HPT and others NCDs. Among the different exercise types and intensities, high intensity interval exercise (HIIT) showed superior benefits for reducing blood pressure (BP) and improving variables involved in the pathophysiology of HPT when compared to continuous moderate-intensity exercise (MICE). However individuals with comorbidities or injures are not capable to follow adequate intensity of both types of exercise. Heated water-based has been used as an option to facilitate the individuals adherence to exercise and positive results especially in BP levels. Despite this, little is known about the effect of HIIT or MICE in heated water-based on BP and other hemodynamic variables involved in the pathophysiology of HPT in older hypertensive individuals. PURPOSE: To evaluate the hemodynamic and autonomic response to a HIIT versus MICE session and in 12 weeks of training in older individuals with hypertension. METHODS: 60 elderly hypertensives of both genders, aged over 60 years, will be randomized in the ratio 2: 2: 1 to 12 weeks of high intensity interval training (HIIT), moderate intensity continuous (MICE) or control follow-up without exercise (CON), respectively. Exercise programs will be discontinued after 12 weeks, and individuals will be followed up for another 12 weeks. Individuals will have their physical (cardiorespiratory and muscular) and functional capacity (walking, sitting and lifting ability), hemodynamic variables (blood pressure, arterial stiffness, endothelial function and cardiovascular response to exercise) and autonomic variables (variability of heart rate) and quality of life assessed before and after 12 and 24 weeks of follow-up. Before the beginning of the follow-up, 20 elderly hypertensive patients will also have a hemodynamic response (ambulatory blood pressure, endothelial function, arterial stiffness) and autonomic (heart rate variability) to a session of HI-HEx, MI-HEx and CON evaluated and compared. The feasibility of HIIE and MICE will also be assessed over the 12 weeks of its implementation. HIIT will consisted of warm up (4 min), 21 min of 1 min high intensity exercise (level 15) and "very hard" (level 17) of the subjective Rating of Perceived Exertion Scale (RPE) alternating with 2 min of walking at intensity between "easy" (level 9) and "fairly easy" (level 11) of the RPE. MICE will performed of 4 min warm up and 26 min of walking or jogging at intensity between "fairly light" (level 11) and " somewhat hard " (level 13) of the RPE.

Inclusion Criteria:

• ≥60 years old;
• Hypertension diagnosed at least 6 months earlier (stage 1 or 2);
• Antihypertensive drug treatment and without dosage alteration at least 3 months earlier;
• Blood pressure inferior to 140/90 mmHg in medical office.

Non-inclusion criteria:

• Smoking individuals;
• Uncontrolled cardiovascular disease;
• Disability;
• Deficit cognitive;

Exclusion Criteria:

• Non 100% participation;
• Change (or stopped) clinical or drug treatment.

Participants who has interest to participated will provide an anamnesis to investigator. The investigator will analyse the IDP eligibility or not-eligibility criteria. The eligibility participant will received a document with study protocol, statistical analysis plan, informed consent form, clinical study report and analytic code informations. Thus, investigators will perform cardiopulmonary exercise test to confirm that IDP will be able to study protocol.

Initial data will be analysed at the initial sessions (cardiopulmonary exercise and functional capacity tests); at the day of sessions (study 1), after 12 weeks and 3 months of training interruption (study 2).

Informed Consent Form described and signed. DP will received Informed Consent Form informing the objectives, study deling, interventions, analyses, risks and benefits. Participation in this study will be voluntary and confidential after signing of an informed consent.

In study 1 and 2 the participants will be aleatory randomized and the main investigator will perform the exercise session. The data will collected and assessed by a blinded investigator without knowledge of participants intervention.