Cardiopulmonary exercise test (CPET)
RPE
HEART
CPET involved an incremental ramp type protocol performed on a treadmill (MicromedAfter warm-up, treadmill speed was set according to age and gender, following the recommendations of the Brazilian Society of Cardiology. The speed was then increased by 0.1 km/h every 10, 20 or 30 seconds until voluntary exhaustion, and participants were verbally encouraged to give their maximum effort. The test lasted between 8 to 12 minutes and ended when participants met the criteria for test interruption according to ACSM guideline (Volunteers were instructed to wear comfortable clothes and avoid vigorous physical exercise (24 hours before the test), alcohol consumption (12 hours before the test) and caffeine (3 hours before the test). CPET was performed in the morning, to avoid the influence of the circadian rhythm. Ambient temperature (22°C - 24°C), relative humidity (40% - 60%) and lighting were controlled according to the preliminary conditions (23). Gas analysis was performed using a CortexHR, BP, rating of perceived exertion (RPE) and ventilatory parameters (peak, carbon dioxide production, respiratory oxygen equivalent, respiratory equivalent of the ventilatory threshold) were monitored and registered during the test. RPE was evaluated according to the Borg 0-10 (27). The instrument presents numerical classification from “0” to “10”, indicating low and maximum intensity effort, respectively. The values indicated by the volunteers were recorded at the end of each minute of the test (5th to 16th minute). Heart rate (HR) was measured by a cardiac monitor (Polar v800, Finland) during the test and up to 10 minutes of rest after its end, with the volunteer in the sitting position. Cardiac monitor was fixed in the chest and with simultaneous transmission to a watch. Data were later transferred and recorded in a specific software (Polar Flow, Finland) for proper analysis.