RS800CX Heart Rate Monitor Research Articles

Associations between heart rate variability and maximal fat oxidation in two different cohorts of healthy sedentary adults

Background and aimsResting heart rate variability (HRV) and maximal fat oxidation (MFO) during exercise are both considered as a noninvasive biomarkers for early detection of cardiovascular risk factors. Thus, this study aimed to analyze the relationship between resting HRV parameters and MFO during exercise, and the intensity of exercise that elicit MFO (Fatmax) in healthy sedentary adults. Methods and resultsA total of 103 healthy young adults (22.2 ± 2.3 years old, 67% female; from the ACTIBATE cohort) and 67 healthy middle-aged adults (53.1 ± 5.0 years old, 52% female; from the FIT-AGEING cohort) were included in this cross-sectional study. HRV was assessed using a Polar RS800CX heart rate monitor, while MFO and Fatmax were determined during a graded exercise treadmill test using indirect calorimetry. No significant associations were observed for healthy young adults (standardized β coefficients ranged from −0.063 to 0.094, and all P ≥ 0.347) and for middle-aged adults (standardized β coefficients ranged from −0.234 to 0.090, and all P ≥ 0.056). Nevertheless, only a weak association was observed between one HRV parameter in time-domain (the percentage of R-R intervals that shows a difference higher than 50 ms [pNN50]) and MFO in the cohort of middle-aged adults (β coefficient = −0.279, and P = 0.033). ConclusionThe results of this study suggest that resting HRV parameters are not associated with MFO and Fatmax during exercise in two independent cohorts of healthy sedentary young and middle-aged adults, respectively.

Effect of resisted exercise on autonomic cardiac modulation in elderly women: STROBE-compliant study.

Heart rate variability (HRV) is an important cardiac health marker, with lower values indicating a reduction in vagal control of cardiac rhythm and decreasing significantly with advancing age. In this study, we evaluated the effects of strength exercises for the upper and lower limbs on cardiac autonomic modulation in elderly women.We registered 29 participants using a portable RS800CX heart rate monitor to record the RR intervals. For the collection of HRV data, the volunteers remained seated at rest for 10 minutes. After the rest period, the participants performed the exercises. Immediately after the exercise protocol, the subjects remained seated at rest for 30 minutes. HRV indices were analyzed in the following periods: rest, 0 to 10 minutes, 5 to 10 minutes, 10 to 20 minutes, and 20 to 30 minutes. Systolic arterial pressure and diastolic arterial pressure were measured in the following periods: rest, immediately after exercise, and 30 minutes after exercise.Regarding the mean of the RR intervals, heart rate, and indexes of the time and frequency domains surveyed, there were no statistically significant differences between the 4 moments in the protocols for upper and lower limbs. No significant differences were found in systolic and diastolic pressures between the 3 time points surveyed in the protocols for the upper and lower limbs.Resistance exercises performed with low-intensity loads and a greater number of repetitions did not promote significant variations in cardiac autonomic modulation and blood pressure levels, showing good safety in elderly women.

Heart rate rather than heart rate variability is better associated with cardiorespiratory fitness in adults

ABSTRACT This study aimed to examine the association of heart rate (HR) and heart rate variability (HRV) with cardiorespiratory fitness (CRF) in adults. This cross-sectional study included 204 participants: 132 young adults (67% women; 22.3 ± 2.3 years) and 72 middle-aged adults (53% women; 53.2 ± 5 years). HR and HRV were measured using a Polar RS800CX heart rate monitor. CRF was assessed using a metabolic cart during an incremental test. HR was negatively associated with CRF relative to body weight (BW) in young adults adjusting for sex, age, and physical activity (β ranged from −0.200 to −0.195; all P ≤ 0.022). These associations disappeared after including fat mass as a covariate (all P ≥ 0.106) while remained significant after adjusting for fat-free mass (FFM; all P ≤ 0.008). Neither HR nor HRV variables were associated with CRF expressed as absolute values or relative to FFM in young and middle-aged adults after adjusting for the abovementioned covariates (all P ≥ 0.074). Our results suggest that HR rather than HRV is better associated with CRF relative to BW in young adults. However, this association seems to be explained by the inclusion of fat mass in the calculation of CRF relative to BW. Highlights Heart rate and heart rate variability variables have been associated with cardiorespiratory fitness. Our present results, and previous literature, suggest that the “simple” measurement of the heart rate could be easier to obtain and interpret than the heart rate variability variables. The heart rate variable rather than the heart rate variability variables is better associated with cardiorespiratory fitness relative to body weight in healthy young adults.

Technical Innovation for Visual Assessment of Preterm Newborns in a Neonatal Intensive Care Unit: Exploratory Study.

Objective The present study is aimed at assessing heart rate variability (HRV) and its correlation with visual acuity (VA) assessment of preterm newborns (PTNB) in neonatal intensive care units. Method Cross-sectional study analyzing HRV during assessment of VA with the aid of a Polar RS800CX heart rate monitor (Polar Electro Oy, Finland). HRV was analyzed according to time and frequency domains and the chaos domain used the autocorrelation coefficient and entropy. The sample consisted of hospitalized PTNB, and static analysis included simple regression diagnosis. Results A total of 14 PTNB were included in the sample. VA varied between 0.23 and 1.60 cpd, and only five PTNB obtained below-expected values for age. Statistical analysis demonstrated a negative correlation between VA and time domain (SDDN and SD2) and a positive correlation between frequency domain (heart rate and hertz), but in simple linear regression analysis, these variables did not influence VA. Conclusion The results of the study demonstrate that visual acuity was inversely correlated with SDNN and SD2 and during stimulation, showing that the higher the visual performance, the lower the autonomic modulation response.

Inter- and intra-researcher reproducibility of heart rate variability parameters in three human cohorts

Heart rate variability (HRV) is a valid and non-invasive indicator of cardiac autonomic nervous system functioning. Short-term HRV recordings (e.g., 10 min long) produce data that usually is manually processed. Researcher subjective decision-making on data processing could produce inter- or intra-researcher differences whose magnitude has not been previously quantified in three independent human cohorts. This study examines the inter- and intra-researcher reproducibility of HRV parameters (i.e., the influence of R–R interval selection by different researchers and by the same researcher in different moments on the quantification of HRV parameters, respectively) derived from short-term recordings in a cohort of children with overweight/obesity, young adults and middle-age adults. Participants were recruited from 3 different studies: 107 children (10.03 ± 1.13 years, 58% male), 132 young adults (22.22 ± 2.20 years, 33% males) and 73 middle-aged adults (53.62 ± 5.18 years, 48% males). HRV was measured using a Polar RS800CX heart rate monitor. The intraclass correlation coefficient (ICC) ranged from 0.703 to 0.989 and from 0.950 to 0.998 for inter-and intra-researcher reproducibility, respectively. Limits of agreement for HRV parameters were higher for the inter-researcher processing compared with the intra-researcher processing. On average, the intra-researcher differences were 31%, 62%, and 80% smaller than the inter-researchers differences based on Coefficient of Variation in children, young and middle-aged adults, respectively. Our study provides the quantification of the inter-researcher and intra-researcher differences in three independent human cohorts, which could elicit some clinical relevant differences for HRV parameters. Based on our findings, we recommend the HRV data signal processing to be performed always by the same trained researcher and we postulate a development of algorithms for an automatic ECG selection.

PO-268 Heart rate variability to assess ventilatory threshold in overweight young men

Objective The individualized training intensity is important in the prevention of overweight and obesity. Our study compared heart rate (HR), oxygen uptake (VO2), and work load (WL) corresponded to the anaerobic threshold during an incremental cycling test between ventilatory (VT) and heart rate variability threshold (HRVT) methods. Further, we examined the validity of three heart rate variability analyses to assess VT in overweight young men.
 Methods Sixteen overweight young men (age 21.1±1.7 years, height 175.3±5.5 cm, weight 84.0±6.7kg, body mass index 27.3±1.2 kg/m2, VO2peak33.6±4.3ml/min/kg ) performed a gradual exercise test on a cycle ergometer (Lode Corival，Lode B.V.，Groningen，Newtherlands).The protocol started at 30 W for 2 minutes with subsequent increments of 30 W every 2 minutes until exhaustion. During test, gas exchanges (VO2, VCO2) and ventilation (VE) were measured by breath-by-breath using Metamax 3B portable analyzer (CORTEX, Biophysik GmbH，Leipzig，Germany). The ventilatory threshold (VT) was identified as the point at which VE for O2 began to rise without a concomitant rise in ventilator equivalent for CO2. The R-R intervals were continuously recorded using a Polar RS800cx HR monitor(Kempele, Finland). HRV data were further analyzed by Kubios HRV analysis software (Kuopio, Finland) based on time-domain (RMSSD) , Poincare plots(SD1) and time-varying spectral (fHF×HFP) methods. Data were analyzed using SPSS 22.0. Normal distribution of variables was verified by Kolmogorov-Smirnov test. The relationship between HRVT variables and VT was assessed using paired t-test and Pearson’s production correlation. The magnitude of concordance between the methods was further evaluated by Bland-Altman plots.
 Results No significant difference was witnessed in HR, VO2, and WL related to AT between HRVT and VT methods（P<0.05）. The relationships were found between the methods to determine the AT for all variables analyzed (r=0.40-0.91). Additionally, the Bland-Altman plots revealed that findings showing narrow limits of agreement present for fHF×HFP and the VT whilst the association between RMSSD, SD1 and VT showed wider limits.
 Conclusions The estimation of the HRVT, especially derived through the time-varying spectral (fHF×HFP), may be a noninvasive and more robust method to determine the VT, which could be used to adapt individualized training intensity to overweight young men for training prescription.

Validation of the Polar RS800CX for assessing heart rate variability during rest, moderate cycling and post-exercise recovery

Background: Heart rate variability (HRV) is an autonomic nervous system marker that provides reliable information for both disease prevention and diagnosis; it is also used in sport settings. We examined the validity of the Polar RS800CX heart rate monitor during rest, moderate cycling, and recovery in considering the total of 24 HRV indices. Method: A total of 32 healthy males (age=24.78±6.87 years, body mass index=24.48±3.13 kg/m2) completed a session comprised by three 20-minute time periods of resting, cycling at 60% of maximal heart rate, and recovery using a Polar RS800CX and an electrocardiogram (ECG) monitors. The HRV indices included time-domain, frequency-domain, Poincaré plot and recurrence plot. Bland–Altman plot analysis was used to estimate agreement between Polar RS800CX and ECG. Results: We detected significant associations (r>0.75, p<0.05) in all HRV indices, while five out of 24 HRV indices displayed significant mean differences (p<0.05) between Polar RS800CX and ECG during the resting period. However, for the exercise and recovery periods, we found significant mean differences (p<0.05) in 16/24 and 22/24 HRV indices between the two monitors, respectively. Conclusion: It is concluded that Polar RS800CX is a valid tool for monitoring HRV in individuals at resting conditions, but it displays inconsistency when used during exercise at 60% of maximal heart rate and recovery periods.

Heart Rate Variability And Autonomic Activity In A Nonfunctional Overreached Professional Soccer Player

PURPOSE: In order to investigate nonfunctional overreaching (NFOR) related adaptations in the autonomic nervous system, heart rate variability (HRV) was examined in a professional soccer player (age: 28.6 years; weight: 77.4 kg; height: 177.1 cm; adiposity: 12.1 %; VO2 Max 57 ml/kg/min) who showed reduced performance in competitions, frequent muscular fatigue during some training sessions (same period), and finally getting upper respiratory tract infection (URTI). METHODS: HRV analysis was performed once a week during three periods of competitive season: initial, NFOR state and post-recovery (5-month follow-up). Short-term recordings (5 minutes) were made with a Polar RS800CX heart rate monitor in two positions: supine (S) and 90° head-up tilt (T), immediately after awakening (match day morning). Root mean square of successive differences (RMSSD) and power spectral density were measured. LF/HF ratios in S and T positions were calculated and mean resting heart rate (RHR) was also analyzed. Seven players from the same team and with normal performances during the season were used as a control group (age: 26.6 ± 3.1 years; weight: 73.2 ± 6 kg; height: 176.7 ± 10 cm; adiposity: 12.9 ± 1.6 %; VO2 Max 55.7 ± 1.8 ml/kg/min). The typical 95% confidence interval (CI) in every HRV parameter was calculated in this group. To be diagnosed as NFOR, the subject (case) had to reveal a 95% difference with respect to the lower or upper CI limit reported in the control group. Values are expressed as mean ± SD. RESULTS: LF/HF ratio decreased progressively throughout the competitive period in S and it was substantially different in comparison with control subjects in T during the NFOR state (0.26 ± 0.62 vs. 2.03 ± 1.25). Relevant differences of RMSSD in S (107.6 ± 20.2 vs. 74.6 ± 23.8 ms) and T (140.3 ± 15.3 vs. 61.6 ± 21.6 ms) were found in NFOR. According to this phenomenon, RHR was lower than the control group in S (45.3 ± 1.7 vs. 55.7 ± 6.5 bpm) and T (48.2 ± 2.4 vs. 59.8 ± 9.1 bpm) and returned to baseline after recovery. CONCLUSIONS: The results suggest a sympathovagal imbalance with extensive parasympathetic modulation in a player identified as overreached. Relevant increase of RMSSD and decrease of LF/HF ratio reflect alterations in autonomic function, which should be taken into account when complete recovery is essential to prevent overtraining syndrome.

Effects of elevation change on mental stress in high-voltage transmission tower construction workers

High-voltage transmission tower construction is a high-risk operation due to the construction site locations, extreme climatic factors, elevated working surfaces, and narrow working space. To comprehensively enhance our understanding of the psychophysiological phenomena of workers in extremely high tower constructions, we carried out a series of field experiments to test and compare three working surface heights in terms of frequency-domain heart rate variability (HRV) measurements. Twelve experienced male workers participated in this experiment. The dependent variables, namely, heart rate (HR), normalized low-frequency power (nLF), normalized high-frequency power (nHF), and LF-to-HF power ratio (LF/HF), were measured with the Polar RS800CX heart rate monitor. The experimental results indicated that the task workload was similar between working surface heights. Tower construction workers perceived an increased level of mental stress as working surface height increased.

Heart rate variability in practitioners of hippotherapy with down syndrome

Background: Down syndrome (DS) can lead to motor, cognitive, and socio-affective disorders, and hippotherapy is one therapeutic modality. Alterations in heart rate (HR), defined as heart rate variability (HRV), are modulate by autonomous nervous system. However, many descriptions in the research literature on HRV in practitioners of hippotherapy with DS were not found. The hypothesis of this study is that hippotherapy can generate an increase in HRV in practitioners with DS due to the stimuli offered by the activity and movement of the horse. Purpose: To evaluate heart rate variability in practitioners of hippotherapy with DS before, during and after their practice. Methods: For this study, 6 children with Down syndrome, mean age 12± 1.6 years were recruited. The HR was obtained and calculated by the uptake of RR intervals (R-Ri) of the electrocardiogram, with a cardiofrequencimetre (Polar® RS800CX Heart Rate Monitor – Kempele – Finland), for 5 sessions of hippotherapy for 30 minutes once weekly. HR was collected before, during and after each session. For all statistical analysis, Sigma-Stat® Software version 3.5 was used and a significance level of p value lower than 5% (p< 0.05) were considered. Results: In the data analysis but with no significant results tended to decrease parasympathetic activity at rest, observed by rMSSD indices (square root of the mean squared differences between successive normal intervals) and pNN50 (percentage of adjacent RR intervals differing by duration 50 ms) between the first and fifth sessions. In the frequency domain values of HF (high frequency) have not changed. With respect to sympathetic activity observed at LF index (low frequency), we noted increasing trend. Was also found a significant decrease in parasympathetic activity (p= 0.031), observed by pNN50 index when comparing the behavior of the HR during the first and fifth sessions of hippotherapy in rMSSD index showed a tendency to decrease. In the frequency domain, there were no significant difference in the analyzed components, however, tended to increase in LF and decrease in HF comparing the period during sessions of hippotherapy. Conclusion(s): Through the proposed study it was concluded that during hippotherapy sessions pure threedimensional motion as well as the environment of a hippotherapy centre did not improve HRV in children with DS, so not confirming the hypothesis. Implications: This study showed that the threedimensional movement of the horse alone did not increase heart rate variability in children with DS. Further studies with a larger sample size and longer time should be performed in order to confirm whether HRV can be improved or not by hippotherapy.

Comparison of Polar® RS800CX heart rate monitor and electrocardiogram for measuring inter-beat intervals in healthy dogs

The aim of the present study was to assess the criterion validity, relative reliability and level of agreement of Polar® RS800CX heart rate monitor measuring inter-beat intervals (IBIs), compared to simultaneously recorded electrocardiogram (ECG) in dogs. MethodsFive continuous minutes of simultaneously recorded IBIs from Polar® RS800CX and Cardiostore ECG in 11 adult healthy dogs maintaining standing position were analyzed. Polar® data was statistically compared to ECG data to assess for systematic differences between the methods. Three different methods for handling missing IBI data were used. Criterion validities were calculated by intraclass correlation coefficients (ICCs) and corresponding 95% confidence intervals (CIs). Relative reliabilities and levels of agreement were calculated by ICCs and the Bland and Altman analysis for repeated measurements per subject. ResultsCorrelation coefficients between IBI data from ECG and Polar® RS800CX varied between 0.73 and 0.84 depending on how missing values were handled. Polar® was over- and underestimating IBI data compared to ECG. The mean difference in log transformed (base10) IBI data was 0.8%, and 93.2% of the values were within the limits of agreement. Internally excluding three subjects presenting IBI series containing more than 5% erroneous IBIs resulted in ICCs between 0.97 and 0.99. Bland and Altman analysis (n=8) showed mean difference was 1.8ms, and 98.5% of the IBI values were plotted inside limits of agreement. ConclusionThis study showed that Polar® systematically biased recorded IBI series and that it was fundamental to detect measurement errors. For Polar® RS800CX heart rate monitor to be used interchangeably to ECG, by showing excellent criterion validity and reliable IBI measures in group and individual samples, only less than 5% of artifacts could be accepted.

Research on the relationship between clothing pressure developed by women's basketball sports bra and heart rate variation indexes

Purpose – The purpose of this paper is to clarify the relationship between dynamic clothing pressure of women's sports bras and heart rate variation indexes during playing basketball. Design/methodology/approach – Totally, 35 healthy females aged between 20 and 24 were employed as subjects. Their heart rate variability (HRV) data and the clothing pressure values when wearing sports bras of different bust sizes during playing basketball were measured using Polar RS800CX heart rate monitor and Flexi Force201 thin film type pressure sensor with MFF series pressure test system. Their subjective comfort evaluations were conducted by five-point Likert scale. Grey correlation analysis is used to determine the correlation degree of heart rate variation indexes and subjective comfort evaluations to identify the indexes preferably associated with subjective comfort. Multiple regression analysis is applied to investigate multiple correlations between pressure of test points and the indexes selected above. Findings – Combined subjective comfort evaluation with objective HRV evaluation the heart rate variation indexes preferably associated with subjective comfort of these bras were identified, which includes mHR, mRR, RMSSD, pNN50. By the relationship between dynamic clothing pressure and the indexes above, this study finds that the clothing pressure of the chest area during basketball exercise should be controlled in the range of 2.01-4.74 kPa. Research limitations/implications – The subjects of different body type should be taken into account. Further, the mathematic models from this study show low R2-value so the models should be provided more reliable prediction. Originality/value – The present study indicates that there is an inevitable connection between heart rate variation indexes and subjective comfort of basketball sports bras and creatively points out that heart rate variation indexes can partly assess the comfortable clothing pressure. The study can offer theoretical basis for sports apparel industry to develop the comfortable basketball sports bra.

Validity and reliability of Polar® RS800CX heart rate monitor, measuring heart rate in dogs during standing position and at trot on a treadmill

The aim of the present study was to assess criterion validity, and relative and absolute reliability of Polar® RS800CX heart rate monitor, compared to simultaneously recorded electrocardiogram (ECG) data, in measuring heart rate of dogs during standing position and at trot on a treadmill. MethodsHeart beats from Polar® RS800CX and Cardiostore ECG were recorded simultaneously during seven continuous minutes in standing position and at trot, in 10 adult healthy dogs. Polar® data was statistically compared to ECG data for a variety of mean beats per minute (BPM), standard deviation and confidence interval. Criterion validity was calculated by Pearson product moment correlation method and intraclass correlation coefficient (ICC2.1). Relative and absolute reliability were calculated by ICC2.1, the Bland and Altman analysis and standard error of measurement (SEM and SEM%). ResultsThe correlation, criterion validity, between Polar® and ECG data in standing position was r=0.99 (p<0.0005) and at trot r=0.97 (p<0.0005). Polar® data was not significantly different from ECG data. Mean difference between ECG and uncorrected Polar® data was −0.6BPM in standing position and −0.6BPM at trot. Polar® was over- and underestimating ECG data. SEM and SEM% in standing were ±2.6BPM and 3.0%, at trot ±3.8BPM and 3.1%, indicating that measurement errors were low. ConclusionThis study showed that the criterion validity and the instrument reliability were excellent in Polar® RS800CX heart rate measuring system. The equipment seemed to be valid and reliable in measuring BPM in the dogs studied during submaximal cardiovascular conditions such as in standing position and at trot on a treadmill.

Investigating the autonomic nervous system and cognitive functions as potential mediators of an association between cardiovascular disease and driving performance

Cardiovascular disease (CVD) impacts the autonomic nervous system and cognitive functions related to activities of daily living, including driving an automobile. Although CVD has been linked to unsafe driving, mechanisms underlying this relationship remain elusive. The aim of this study was to examine the role of cognitive functions and the autonomic nervous system as potential mediators of driving performance. Nineteen individuals having recently suffered a cardiac event and 16 individuals with no history of CVD completed a simulated drive using a STISIM simulator to assess driving performance. Heart rate was recorded throughout testing using a Polar RS800CX heart rate monitor, and measures of executive, orienting, and alerting functions were obtained through the Attention Network Test. We used the Baron and Kenny analysis method to assess potential mediating effects of the relationship between CVD and driving performance. Executive function was the only potential mediator investigated to be associated with driving (p < 0.01) and CVD (p < 0.05); however, it did not appear to play a mediating role (p = 0.28). These results suggest that individuals with CVD exhibit decrements in complex cognitive tasks such as driving and that further research is needed to better understand the mechanisms underlying this relationship.