Evaluation of Vascular Responses to Moderate-intensity Continuous and High-intensity Interval Physical Exercise in Individuals With Prehypertension: a Randomized Trial

Individuals with prehypertension, diagnosed according to the 7th Brazilian Guidelines on Hypertension with the presence of systolic blood pressure (SBP) between 121 and 139 and / or diastolic (DBP) between 81 and 89 mmHg, are more likely to become hypertensive and to develop cardiovascular complications. Moreover, they already have alterations in the function of large arteries that may play a role in the development of the disease in the future. An option in the prevention / treatment of hypertension is the moderate intensity physical training, but high intensity interval training offers the possibility of greater exercise adherence, since it can be performed with less volume and less time spent, with the same benefits than moderate exercise, or even higher, being preferred by the population. Among these benefits, the investigators can mention the post-exercise hypotension (PEH) which occurs in normotensive, prehypertensive, and hypertensive individuals, due the decreased in sympathetic nerve activity and improved in vascular function. Also, selected participants with prehypertension can present a profile of masked hypertension, identified only by 24 hours ambulatory BP monitoring (ABPM). Given the possible differences between vascular responses to exercise intensities, the investigators intend to compare, in prehypertensive patients, the vascular responses of large arteries by noninvasive methods and PEH to a session of high intensity exercise and a session of moderate intensity continuous exercise. In addition, to study some of the possible physiological variables involved in this response by measuring heart rate variability. It is expected to find differences in vascular responses according to the presence of masked hypertension. Twenty two prehypertensive individuals aged between 30 and 60 years of both sexes will be studied. Subjects will perform cardiopulmonary testing and baseline vascular measurements (central pressure and pulse wave velocity measurements by three different methods), as well as 24 -hour ABPM. The vascular measurements will be repeated immediately after, and 24 hours after each session. Each participant will perform the session of one type of exercise in one day, and after three days will perform the other, with random distribution to the sequence of exercise type. Participants will perform 24-hour ABPM prior to exercise and for 24 hours after each exercise session. Data will be compared by appropriate statistical analysis.