Two protocols of aerobic exercise modulate the counter-regulatory axis of the renin-angiotensin system

Aims: The renin-angiotensin system (RAS) is a dual system with two opposite arms: i) the classical one formed by the angiotensin converting enzyme (ACE), angiotensin (Ang) II and angiotensin type 1 (AT1) receptors; ii) the counter-regulatory arm consisting of ACE2, Ang-(1-7) and Mas receptor. Physical exercise can modulate this system, however, only animal studies have compared the effects of different intensity protocols on the RAS. No data with humans were provided. Therefore, we investigated the acute effect of two protocols of isowork aerobic exercise [High-Intensity Interval Exercise (HIIE) and Moderate-Intensity Continuous Exercise (MICE)] in plasma and urinary levels of RAS components in physically active men. Main methods: The HIIE protocol included a 5-minute warm-up cycling at 60-70% of heart rate peak (HRp) intensity followed by 10 sets of 30 s above 90% with 1 min of recovery and 3 min of cool down. The MICE protocol was performed at a constant power corresponding to 60-70% of HRp and finalized at the same total work of HIIE. Blood and urine samples were collected before and after the protocols. Plasma and urinary levels of ACE, ACE2, Ang-(1-7) and Ang II were analyzed by enzyme-linked immunoassay. Key findings: While the HIIE protocol significantly increased urinary levels of ACE and plasma levels of ACE2, the MICE protocol elevated urinary concentrations of ACE2 and of Ang-(1-7). A greater increase of urine concentrations of Ang-(1-7) occurred in the MICE if compared with the HIIE protocol. Significance: Aerobic physical exercise acutely increases the activity of the counter-regulatory RAS axis, mostly the MICE protocol.