Impact of L-citrulline Associated With L-arginine Supplementation on the Post-exercise Hypotension in Normotensives and Hypertensives

Participants After sample size calculation (see statistical analysis session), 40 hypertensives and 40 normotensive sedentaries will be recruited to this study. All volunteers (both sexes) will be adults without osteoarticular disabilities and they will need a medical authorization to physical exercise practice. Participants will be recruited from an exercise program project linked to the university that offered stretching and functional exercises sessions to the external community. The study follow the Declaration of Helsinki and the Institutional Ethics Committee approved all experimental procedures and protocols. Each participant will be fully informed of all potential risks and experimental procedures, after which, informed written consent will be signed. Table 1 shows the basics characteristics of the participants.

Study design A double-blind crossover randomized clinical trial will be conducted. After the minimum interval (48 hours), the subjects will be randomly (using a random number table - https://www.random.org/) submitted to four experimental situations (exercise/L-citrulline, exercise/L-arginine, exercise/placebo, exercise/L-citrulline + L-arginine). The participants will ingested a sachet, which contained L-citrulline malate (6 grams) or L-arginine (8 grams) or placebo (6 grams of corn starch) dissolved in water.

The substances will be ingested 120 minutes before the experimental or control session. Anthropometric measures will be taken before the rest period. The exercise session consisted of 5 min to warm up (50% of 65% HRreserve) and 40 minutes of run/walk at 60-70% HRreserve (or 12-14 ratings of perceived exertion [RPE](1) if take some beta-blocker medicines) in a treadmill. This will be followed by a progressive cooldown (5 minutes). In the control session, the participants will be remained seated in a quiet room for 40 min.

After the exercise/control sessions, the blood pressure will be measured every 10 minutes over the course of 60 minutes and the heart rate variability will be recorded continuously for 60 minutes (laboratorial phase). Then, 15 minutes will be given to the participants to take a shower and change the clothes before the ambulatory blood pressure device be attached on their arm. The ambulatory blood pressure will be recorded over 24 hours. In the next day, the participants will be asked to return to the laboratory to remove the device.

Anthropometry The weight will be measured by the digital anthropometric scale (Urano, OS 180A, Canoas, Brasil), with accuracy of 0.1kg and height will be measured by stadiometer with accuracy of 0.1cm, in accordance with the procedures described by Gordon et al (2). The body mass index (BMI) will be defined as the body mass (kg) divided by the square of the body height.