Validity of the Wrist-Worn Polar Vantage V2 to Measure Heart Rate and Heart Rate Variability at Rest

Heart rate (HR) and heart rate variability (HRV) can be monitored with wearable devices throughout the day. Resting HRV in particular, reflecting cardiac parasympathetic activity, has been proposed to be a useful marker in the monitoring of health and recovery from training. This study examined the validity of the wrist-based photoplethysmography (PPG) method to measure HR and HRV at rest. Recreationally endurance-trained participants recorded pulse-to-pulse (PP) and RR intervals simultaneously with a PPG-based watch and reference heart rate sensor (HRS) at a laboratory in a supine position (n = 39; 5-min recording) and at home during sleep (n = 29; 4-h recording). In addition, analyses were performed from pooled laboratory data (n = 11340 PP and RR intervals). Differences and correlations were analyzed between the HRS- and PPG-derived HR and LnRMSSD (the natural logarithm of the root mean square of successive differences). A very good agreement was found between pooled PP and RR intervals with a mean bias of 0.17 ms and a correlation coefficient of 0.993 (p < 0.001). In the laboratory, HR did not differ between the devices (mean bias 0.0 bpm), but PPG slightly underestimated the nocturnal recordings (bias −0.7 bpm, p < 0.001). PPG overestimated LnRMSSD both in the laboratory (bias 0.20 ms, p < 0.001) and nocturnal recordings (bias 0.17 ms, p < 0.001). However, very strong intraclass correlations in the nocturnal recordings were found between the devices (HR: 0.998, p < 0.001; LnRMSSD: 0.931, p < 0.001). In conclusion, PPG was able to measure HR and HRV with adequate accuracy in recreational athletes. However, when strict absolute values are of importance, systematic overestimation, which seemed to especially concern participants with low LnRMSSD, should be acknowledged.

Effect of Mental Activity on Heart Rate, Heart Rate Variability and Respiratory Rate in Healthy Volunteers

Introduction: The link between mental stress and cardiac autonomic regulation plays a significant role in the patho physiological process of cardio neural feedback loop. This study assessed the effect of mental arithmetic and silent reading on heart rate variability, heart rate and respiratory rate in young healthy volunteers. Materials and Methods: R-R intervals were recorded for five minutes in ten healthy volunteers aged 22-24 years of either sex while resting, doing mental arithmetic, and silent reading in a sitting position. Time and frequency domain approaches were used to measure heart rate variability (HRV). In them, heart rate and respiratory rate were also calculated. Using the paired ‘t' test, mean differences in values were evaluated between resting and mental arithmetic; resting and quiet reading conditions. Results: Heart rate and respiratory rate were significantly higher during mental arithmetic (p = 0.012, p<0.0001 respectively) and silent reading compared to resting state (p=0.005, p=0.0002 respectively). There was no significant change in HRV during mental arithmetic and silent reading compared to resting state. Conclusion: Mental arithmetic and silent reading primarily evoke a rise in respiratory rate and heart rate.

A Cardiac Force Index Applied to the G Tolerance Test and Surveillance among Male Military Aircrew

Military aircrew are occupationally exposed to a high-G environment. A tolerance test and surveillance is necessary for military aircrew before flight training. A cardiac force index (CFI) has been developed to assess long-distance running by health technology. We added the parameter CFI to the G tolerance test and elucidated the relationship between the CFI and G tolerance. A noninvasive device, BioHarness 3.0, was used to measure heart rate (HR) and activity while resting and walking on the ground. The formula for calculating cardiac function was CFI = weight × activity/HR. Cardiac force ratio (CFR) was calculated by walking CFI (WCFI)/resting CFI (RCFI). G tolerance included relaxed G tolerance (RGT) and straining G tolerance (SGT) tested in the centrifuge. Among 92 male participants, the average of RCFI, WCFI, and CFR were 0.02 ± 0.04, 0.15 ± 0.04, and 10.77 ± 4.11, respectively. Each 100-unit increase in the WCFI increased the RGT by 0.14 G and the SGT by 0.17 G. There was an increased chance of RGT values higher than 5 G and SGT values higher than 8 G according to the WCFI increase. Results suggested that WCFI is positively correlated with G tolerance and has the potential for G tolerance surveillance and programs of G tolerance improvement among male military aircrew.

Heart rate as a measure of emotional arousal in evolutionary biology

How individuals interact with their environment and respond to changes is a key area of research in evolutionary biology. A physiological parameter that provides an instant proxy for the activation of the automatic nervous system, and can be measured relatively easily, is modulation of heart rate. Over the past four decades, heart rate has been used to assess emotional arousal in non-human animals in a variety of contexts, including social behaviour, animal cognition, animal welfare and animal personality. In this review, I summarize how measuring heart rate has provided new insights into how social animals cope with challenges in their environment. I assess the advantages and limitations of different technologies used to measure heart rate in this context, including wearable heart rate belts and implantable transmitters, and provide an overview of prospective research avenues using established and new technologies, with a special focus on implications for applied research on animal welfare. This article is part of the theme issue ‘Measuring physiology in free-living animals (Part II)’.

The Subjective Comfort Test of Autism Hug Machine Portable Seat

This preliminary study proposes to investigate (i) the mean comfortable deep pressure of Autism Hug Machine Portable Seat (AHMPS) manual pull and inflatable wrap models; and (ii) the effect of using AHMPS in reducing anxiety in children with autism spectrum disorder (ASD). The first phase was done to determine the comfort test. Fifteen healthy adolescents (13 men and 2 women; aged 19-25 years) individuals volunteered to participate in the comfort test in determining the pressure of AHMPS, both manual pull, and inflatable wrap. The second phase was completed in children with ASD, in which the comforting pressure from the first phase was then applied to five children with ASD (4 boys and 1 girl; aged 8-15 years) from the Putra Mandiri Public Special School Semarang. All children were administered both the AHMPS inflatable wrap and manual pull as a deep pressure apparatus while traveling by bus. A pulse oximeter was used to measure heart rate variability (physiological arousal). The mean comfort pressure was obtained from 15 healthy subjects, which was 0.81 psi on the chest and 0.80 psi on the thigh for the manual pull; and 0.65 psi on the chest and 0.45 psi on the thigh for the inflatable wrap. In the second phase, the AHMPS manual pull did not significantly decrease heart rate with p=0.114, but the AHMPS inflatable wrap significantly decreased heart rate with a significance value of p=0.037. We conclude, therefore, the AHMPS inflatable wrap decreases physiological arousal in children with ASD.

Beholden: The Emotional Effects of Having Eye Contact While Breaking Social Norms

This study looks into the role that eye contact plays in helping people to control themselves in social settings and to avoid breaking social norms. Based on previous research, it is likely that eye contact increases prosocial behavior via heightened self-awareness and increased interpersonal synchrony. In our study, we propose that eye contact can also support constructive social behavior by causing people to experience heightened embarrassment when they are breaking social norms. We tested this in a lab experiment (N = 60) in which participants read insults at the experimenter (i.e., they exhibited norm breaking behavior). In the experimental condition, participants maintained eye contact with the experimenter. In the control condition, the experimenter did not maintain eye contact. We measured embarrassment with a self-report measure, heart rate to capture arousal, and two observational indicators of embarrassment (hesitation and laughter). In line with our hypotheses, having eye contact during norm breaking behavior as compared to no eye contact led to a stronger increase in self-reported embarrassment, a higher heart rate as well as more hesitation and more laughter. We conclude that eye contact does indeed lead to more embarrassment, while breaking social norms. This implies that eye contact gives people the power to punish norm breaking in others by inducing an aversive emotional experience.

Wearable Wireless Physiological Monitoring System Based on Multi-Sensor

The purpose of wearable technology is to use multimedia, sensors, and wireless communication to integrate specific technology into user clothes or accessories. With the help of various sensors, the physiological monitoring system can collect, process, and transmit physiological signals without causing damage. Wearable technology has been widely used in patient monitoring and people’s health management because of its low-load, mobile, and easy-to-use characteristics, and it supports long-term continuous work and can carry out wireless transmissions. In this paper, we established a Wi-Fi-based physiological monitoring system that can accurately measure heart rate, body surface temperature, and motion data and can quickly detect and alert the user about abnormal heart rates.

Electrical Properties of Textiles Treated with Graphene Oxide Suspension

Two-dimensional nanomaterials such as graphene can provide various functional properties to textiles, which have great potential in sportswear, healthcare etc. In this study, the properties of nylon and cotton-based electronic textiles coated with reduced graphene oxide are investigated. After reduction of graphene oxide coating in hydrazine vapor, e-textiles with a resistance of ~350 Ω/sq for nylon, and ~1 kΩ/sq for cotton were obtained. Cyclic mechanical bending tests of samples showed that the resistance increases during bending up to 10–20%. The use of bovine serum albumin as an adhesive layer improved the wash stability for samples with nylon up to 40 washing cycles. The use of BF-6 glue as a protective layer reduced changes in resistance during bending, and improved wash stability of cotton samples. It was shown that the resistance of the obtained samples is sensitive to changes in temperature and humidity. In addition, obtained e-textiles attached to a person’s wrist were able to measure heart rate. Thus, the obtained electronic textiles based on cotton and nylon coated with reduced graphene oxide demonstrates good characteristics for use as sensors for monitoring vital signs.

Using smart speakers to contactlessly monitor heart rhythms

Heart rhythm assessment is indispensable in diagnosis and management of many cardiac conditions and to study heart rate variability in healthy individuals. We present a proof-of-concept system for acquiring individual heart beats using smart speakers in a fully contact-free manner. Our algorithms transform the smart speaker into a short-range active sonar system and measure heart rate and inter-beat intervals (R-R intervals) for both regular and irregular rhythms. The smart speaker emits inaudible 18–22 kHz sound and receives echoes reflected from the human body that encode sub-mm displacements due to heart beats. We conducted a clinical study with both healthy participants and hospitalized cardiac patients with diverse structural and arrhythmic cardiac abnormalities including atrial fibrillation, flutter and congestive heart failure. Compared to electrocardiogram (ECG) data, our system computed R-R intervals for healthy participants with a median error of 28 ms over 12,280 heart beats and a correlation coefficient of 0.929. For hospitalized cardiac patients, the median error was 30 ms over 5639 heart beats with a correlation coefficient of 0.901. The increasing adoption of smart speakers in hospitals and homes may provide a means to realize the potential of our non-contact cardiac rhythm monitoring system for monitoring of contagious or quarantined patients, skin sensitive patients and in telemedicine settings.