Comparison of Polar 810s and an ambulatory ECG system for RR interval measurement during progressive exercise

Ambulatory heart rate monitors and clinical electrocardiographic (ECG) devices are capable of measuring the length of consecutive cardiac periods (RR intervals). The aim of the study was to assess the agreement between the Polar 810s heart rate monitor (Polar) and the Reynolds digital ambulatory ECG using Pathfinder software version 8.4 (Reynolds v8.4) during cycle ergometry. For this purpose, eight subjects completed incremental cycling exercise that began at 60 W and increased by 30 W each 2-minute period until volitional fatigue. Simultaneous recording of the ECG (Reynolds Pathfinder), RR interval (Polar), and respiratory parameters (Metamax 3B) were undertaken at rest and throughout the exercise period. No significant differences were found in RR intervals measured by Polar and Reynolds v8.4 at any relative intensity. Polar and Reynolds v8.4 displayed strong linear relationships at all relative intensities (r2=0.927 to 0.998). Bland and Altman analyses between Polar and Reynolds v8.4 consistently demonstrated minimal bias in absolute RR interval (100 % of mean of paired means) were identified in UF at intensities > 40 % VO2max, HF at intensities > 60 % VO2max and LF during exercise at 80-100 % VO2max. These findings demonstrate that RR intervals and heart rate measurements obtained using Polar and Reynolds v8.4 are in good agreement. However, caution should be exercised when interpreting spectral analysis of RR interval data derived from different acquisition systems during physical activity

Influence of high-frequency bandwidth on heart rate variability analysis during physical exercise

Heart rate variability (HRV) analysis of beat-to-beat RR interval data was performed in 11 asymptomatic young male subjects during a progressive bicycle exercise test. RR interval data (Polar S810) and breath-by-breath respiratory data (rate, minute ventilation and oxygen uptake) (Oxycon Pro) were simultaneously recorded throughout exercise. ‘Ventilation per second’ was defined as ˙VEsec, the change (from the previous epoch) in ventilatory volume per second. Power spectral analysis quantified power distribution of RR data within the bandwidths 0.04–0.15 Hz (LF), 0.15–0.4 Hz (HF0.4), 0.15–1.0 Hz (HF1.0), 0.15–2.0 Hz (HF2.0) and 0.15 to VEsec (HFVEsec). Absolute powers within the LF and all HF bandwidths decreased continuously throughout exercise (exercise intensity range 18 1 to 81 1% ˙VO2max). At mild-to-moderate exercise intensities (18± 1 to 55±1%VO2max) there were no significant differences between the LF/HF ratios calculated using each of the band-limited HF components. However, at moderate-to-high intensities (64± 1 to 81±1%VO2max) there was a significant difference between LF/HF0.4 and the LF/HF ratios calculated using each of the broader HF bandwidths (P < 0.05). In addition, LF/HF1.0 was significantly greater than both LF/HF2.0 and LF/HFVEsec at the highest exercise intensity (81± 1%VO2max). These results suggest that the upper HF bandwidth limit should be extended to dynamically match VEsec when quantifying HRV during moderate-to-high intensity exercise. When the simultaneous recording of respiratory data is not practical, an HF bandwidth upper limit of 2.0 Hz would be an appropriate choice

Rate of reduction of heart rate variability during exercise as an index of physical work capacity

Breathing rates during physical exercise suggest that, during these conditions, the high-frequency (HF) bandwidth of heart rate variability (HRV) analysis should be extended beyond conventional guidelines. However, there has been little investigation of the most appropriate choice of HF bandwidth during exercise. HRV analysis was performed in 10 males and six females during progressive bicycle exercise. Cardiac cycle (RR) interval and breath-by-breath respiratory data were simultaneously recorded. HRV powers were determined for the band-limited ranges 0.04-0.15 Hz [low-frequency (LF)], 0.15-0.4 Hz (HF 0.4) and 0.15-bf Hz (HF bf, where bf represents maximum breathing frequency). Mono-exponential functions described the relationship between HRV and work rate for each bandwidth (r=0.92-0.95) and were used to calculate the "HRV decay constant" (work rate associated with a 50% reduction in HRV power). The HRV decay constants for each bandwidth were linearly related to maximal work rate (r>0.71; P<0.001) and were substantially greater in males than in females (P<0.001). There was a significant difference between the HRV decay constants for HF 0.4 and HF bf (P<0.005) in both genders. The HRV decay constants for the LF and HF bf bandwidths appear to provide an indication of work capacity from submaximal exercise, without prior assumption regarding heart rate and its relationship with work rate

Communication skills for business professionals

Communication Skills for Business Professionals is a student-friendly introduction to the principles and practice of effective communication in the workplace. Engagingly written and full of real-life examples, it explains the key theories underpinning communication strategies and encourages students to consider how to apply them in a contemporary business environment

Streamlined data-gathering techniques to estimate the price and affordability of healthy and unhealthy diets under different pricing scenarios

Objective: To determine the reliability of streamlined data-gathering techniques for examining the price and affordability of a healthy (recommended) and unhealthy (current) diet. We additionally estimated the price and affordability of diets across socio-economic areas and quantified the influence of different pricing scenarios. Design: Following the Healthy Diets Australian Standardised Affordability and Pricing (ASAP) protocol, we compared a cross-sectional sample of food and beverage pricing data collected using online data and phone calls (lower-resource streamlined techniques) with data collected in-store from the same retailers. Setting: Food and beverage prices were collected from major supermarkets, fast food and alcohol retailers in eight conveniently sampled areas in Victoria, Australia (n 72 stores), stratified by area-level deprivation and remoteness. Participants: This study did not involve human participants. Results: The biweekly price of a healthy diet was on average 21 % cheaper (596) than an unhealthy diet (721) for a four-person family using the streamlined techniques, which was comparable with estimates using in-store data (healthy: 594, unhealthy: 731). The diet price differential did not vary considerably across geographical areas (range: 18-23 %). Both diets were estimated to be unaffordable for families living on indicative low disposable household incomes and below the poverty line. The inclusion of generic brands notably reduced the prices of healthy and unhealthy diets (≥20 %), rendering both affordable against indicative low disposable household incomes. Inclusion of discounted prices marginally reduced diet prices (3 %). Conclusions: Streamlined data-gathering techniques are a reliable method for regular, flexible and widespread monitoring of the price and affordability of population diets in areas where supermarkets have an online presence

Towards Enhancing Everyday Pregnancy Care: Reflections from Community Stakeholders in South India

We need a deeper understanding of the everyday challenges of pregnancy care in lower socio-economic settings in India. This paper reports reflections from three workshops involving multiple stakeholders, conducted as part of a larger project exploring the role of digital technology in enhancing everyday practices of pregnancy care. In particular, this paper only reports our initial engagement with community stakeholders in pregnancy care, including the local public and third-sector network of care-workers. Based on the findings, we present three reflections namely, a) tensions between traditional and everyday care practices versus requirements of modern pregnancy care, b) tensions in coordination between multiple stakeholders in pregnancy care, and c) the role of physical and digital infrastructures in pregnancy care. These reflections are introduced as concerns and highlight opportunities to further inform technology design to enhance everyday care of pregnant women in semi-urban and rural India, and beyond

SARS-CoV-2-specific nasal IgA wanes 9 months after hospitalisation with COVID-19 and is not induced by subsequent vaccination

Background: Most studies of immunity to SARS-CoV-2 focus on circulating antibody, giving limited insights into mucosal defences that prevent viral replication and onward transmission. We studied nasal and plasma antibody responses one year after hospitalisation for COVID-19, including a period when SARS-CoV-2 vaccination was introduced. Methods: In this follow up study, plasma and nasosorption samples were prospectively collected from 446 adults hospitalised for COVID-19 between February 2020 and March 2021 via the ISARIC4C and PHOSP-COVID consortia. IgA and IgG responses to NP and S of ancestral SARS-CoV-2, Delta and Omicron (BA.1) variants were measured by electrochemiluminescence and compared with plasma neutralisation data. Findings: Strong and consistent nasal anti-NP and anti-S IgA responses were demonstrated, which remained elevated for nine months (p < 0.0001). Nasal and plasma anti-S IgG remained elevated for at least 12 months (p < 0.0001) with plasma neutralising titres that were raised against all variants compared to controls (p < 0.0001). Of 323 with complete data, 307 were vaccinated between 6 and 12 months; coinciding with rises in nasal and plasma IgA and IgG anti-S titres for all SARS-CoV-2 variants, although the change in nasal IgA was minimal (1.46-fold change after 10 months, p = 0.011) and the median remained below the positive threshold determined by pre-pandemic controls. Samples 12 months after admission showed no association between nasal IgA and plasma IgG anti-S responses (R = 0.05, p = 0.18), indicating that nasal IgA responses are distinct from those in plasma and minimally boosted by vaccination. Interpretation: The decline in nasal IgA responses 9 months after infection and minimal impact of subsequent vaccination may explain the lack of long-lasting nasal defence against reinfection and the limited effects of vaccination on transmission. These findings highlight the need to develop vaccines that enhance nasal immunity. Funding: This study has been supported by ISARIC4C and PHOSP-COVID consortia. ISARIC4C is supported by grants from the National Institute for Health and Care Research and the Medical Research Council. Liverpool Experimental Cancer Medicine Centre provided infrastructure support for this research. The PHOSP-COVD study is jointly funded by UK Research and Innovation and National Institute of Health and Care Research. The funders were not involved in the study design, interpretation of data or the writing of this manuscript