Polar rs800cx monitor

Immediately after each BP measurement, the CAM was measured through HR variability using a Polar RS800CX monitor (PolarElectroOy, Kempele, Finland). The volunteers were seated and the record was made for a minimum of 10 minutes. Data were transferred to a computer provided with the software of the same manufacturer and then transferred to the Kubios HRV software, version 2.0 (University of Kuopio, Finland). Data were analyzed in the time domain, considering the average (MRR) and the standard deviation of the RR (SDNN) individual intervals, the root mean square of successive differences between adjacent RR (RMSSD) and the percentage of successive differences between RR intervals higher than 50 ms (pNN50). In the frequency domain, 0.04 to 0:15 Hz was considered as the low-frequency band (LF) and 0.15 to 0.4 Hz as high-frequency band (HF). The low-ratio frequency/high-ratio frequency were also adopted as sympathetic-vagal balance (LF/HF).

All the tests were performed on a Cyclus 2 ergometer (RBM Elektronik-Automation GmbH, Leipzig, Germany). O₂ consumption (VO₂) and CO₂ production (VCO₂) were measured breath by breath through a mask connected to an O₂ and CO₂ analyzer (MetaMax 3b, Cortex Biophysik, Leipzig, Germany).
Ventilatory parameters were averaged every minute during the submaximal exercise test and the subsequent 10-min recovery period. Heart rate was monitored continuously throughout the duration of the tests (Polar RS800cx monitor, Polar, Finland).

Data were collected in our laboratory under controlled temperature (21°C–25°C) and humidity (50%–60%), and volunteers were instructed to avoid consuming alcohol, caffeine and substances that influence the ANS for 24 hours before evaluation. Data were collected between 8 a.m. and 12 a.m. in order to minimize the interference of circadian rhythm. All procedures necessary for the data collection were explained to the individuals, and the subjects were instructed to remain at rest and to not talking during the data collection.
After the initial evaluation the heart monitor strap was placed on each subject’s thorax over the distal third of the sternum. The HR receiver (Polar RS800CX monitor, Polar Electro OY, Kempele, Finland) was placed on the wrist.
The subject remained 10 minutes seated at rest with spontaneous breathing.

All the tests were performed on a Cyclus 2 ergometer (RBM Elektronik-Automation GmbH, Leipzig, Germany). Oxygen consumption (VO₂) and carbon dioxide (VCO₂) were measured breath by breath through a mask connected to an O₂ and CO₂ analyzer (MetaMax 3b, Cortex Biophysik, Leipzig, Germany). Ventilatory parameters were averaged every minute during the submaximal exercise test and the subsequent 10 min recovery period. Heart rate was monitored continuously throughout the duration of the tests (Polar RS 800cx monitor, Polar, Finland).

All the tests were performed on a Cyclus 2 ergometer (RBM Elektronik-Automation GmbH, Leipzig, Germany). The O₂ consumption (VO₂) and CO₂ production (VCO₂) were measured breath-by-breath through a mask connected to an O₂ and CO₂ analyzer (MetaMax 3b, Cortex Biophysik, Leipzig, Germany).
Ventilatory parameters were averaged every 1 min during the submaximal exercise test and during the subsequent 10-min recovery period. The heart rate was continuously monitored over the duration of the tests (Polar RS800cx monitor, Polar, Finland).

After the initial evaluation, the heart monitor strap was placed on each subject’s thorax over the distal third of the sternum. Besides, the HR receiver (Polar RS800CX monitor, Polar Electro OY, Kempele, Finland) was placed on the wrist.
The R-R intervals recorded by the portable HR monitor (with a sampling rate of 1000 Hz) were downloaded to the Polar Precision Performance program (v. 3.0, Polar lectro, Finland). The software enabled the visualization of HR and the extraction of a cardiac period (R-R interval) file in “txt” format. Following digital filtering complemented with manual filtering for the elimination of premature ectopic beats and artifacts, at least 256 R–R intervals were used for data analysis. Only the series with more than 95% sinus rhythm were included in the study (10 (link), 11 (link)).