Effect of post-resistance exercise hypotension on cerebral hemodynamics and its regulation

• Grant number: 19/22829-3
• Support Opportunities: Scholarships abroad - Research Internship - Doctorate
• Effective date (Start): February 01, 2020
• Effective date (End): March 20, 2020
• Field of knowledge: Health Sciences - Physical Education
• Principal Investigator: Cláudia Lúcia de Moraes Forjaz
• Grantee: Rafael Yokoyama Fecchio
• Supervisor: David Andrew Low
• Host Institution: Escola de Educação Física e Esporte (EEFE). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Research place: Liverpool John Moores University (LJMU), England
• Associated to the scholarship: 18/12390-1 - Effects of dynamic, isometric and combined (dynamic + isometric) resistance training on resting and post-exercise cardiovascular function and regulation in medicated hypertensive men, BP.DR

Abstract

The candidate for this BEPE is developing in Brazil a PhD thesis that aims to evaluate the possible favorable effects of dynamic resistance training on cardiovascular function, decreasing blood pressure (BP) and improving endothelial function. However, during the execution of a dynamic resistance exercise (DRE) session, a large and abrupt increase in BP occurs while a huge decrease is observed immediately after the exercise cessation. Studies have demonstrated that these extreme changes in BP may affect cerebral blood flow both during and immediately after DRE, overcoming the physiological capacity of the cerebral perfusion regulation system. With an extended recovery period from DRE (i.e. 30 to 60 min after the exercise), BP remains below the control levels, producing a clinical benefit called post-resistance exercise hypotension (PREH). However, to the best of our knowledge, no study has evaluated whether cerebral hemodynamics are affected during this extended recovery. Thus, this study will evaluate the influence of PREH on cerebral hemodynamics and regulation. Twelve healthy young men will undergo, in a random order, one DRE (six exercises - 3 sets of 20 repetitions at 50% of 1RM) and one control (60 min rest) session. Pre- and post-interventions, the following variables will be measured: 1) beat-to-beat BP (photoplethysmography); 2) middle cerebral artery blood velocity (CBFV; transcranial Doppler ultrasound); 3) extra-cerebral blood flow in the internal carotid artery (Duplex ultrasound); 4) extra-cerebral endothelial function (30 s of hypercapnia); and 5) cerebral auto-regulation (transfer function between beat-to-beat CBFV and BP). The effects of exercise on such variables will be evaluated by two-factor repeated measures ANOVAs with session (exercise and control) and time (pre and post-intervention) as main factors and the level of significance set at P < 0.05. This project expands the knowledge produced by the student thesis in Brazil, will allow the student to learn new techniques that will be introduced in the Brazilian laboratory after his return, and will consolidate the partnership between the advisors in Brazil and England. (AU)