Cardiac rehabilitation (CR) improves survival in patients with coronary heart disease (CHD), which is largely mediated by the improvements in cardiorespiratory fitness (CRF) defined as peak oxygen consumption (VO₂). Therefore, measuring CRF is essential to predict long-term outcomes in this population. It is unclear, however, whether peak VO₂ achieved at the end of CR (END-peak VO₂) predicts survival or whether the changes of CRF achieved during CR provide a greater prognostic value. To determine whether END-peak VO₂ independently predicts long-term survival in patients with CHD undergoing CR. We also aimed at identifying cut-offs for END-peak VO₂ that could be used in clinical practice. Retrospective analysis of 853 patients with CHD referred to CR who completed a maximal cardiopulmonary exercise test. Survival analysis was performed to examine the risk of all-cause mortality (average follow-up years: 6.65) based on peak VO₂. The Contal and O’Quigley’s method was used to determine the optimal cut-off of END-peak VO₂ based on the log-rank statistic. END-peak VO₂ was inversely associated with mortality risk [hazard ratio (HR) = 0.84; 95% confidence interval (CI) = 0.78–0.90], independent of changes in peak VO₂ adjusted for the baseline peak VO₂. The estimated cut-off of END-peak VO₂ at ≥17.6 mL/kg/min best predicted the survival with high predictive accuracy and patients with END-peak VO₂ under the cut-off had a greater risk of mortality (HR = 2.93; 95% CI = 1.81–4.74). In patient with CHD undergoing CR, END-peak VO₂ is an independent predictor for long-term survival. Studies utilizing higher intensity CR programmes, with and without pharmacologic strategies, to increase peak VO₂ to a greater degree in those achieving a suboptimal END-peak VO₂, are urgently needed.

Background: Cardiorespiratory fitness (CRF) is a predictor of chronic disease that is impractical to routinely measure in primary care settings. We used a new estimated cardiorespiratory fitness (eCRF) algorithm that uses information routinely documented in electronic health care records to predict abnormal blood glucose incidence. Methods: Participants were adults (17.8% female) 20–81 years old at baseline from the Aerobics Center Longitudinal Study between 1979 and 2006. eCRF was based on sex, age, body mass index, resting heart rate, resting blood pressure, and smoking status. CRF was measured by maximal treadmill testing. Cox proportional hazards regression models were established using eCRF and CRF as independent variables predicting the abnormal blood glucose incidence while adjusting for covariates (age, sex, exam year, waist girth, heavy drinking, smoking, and family history of diabetes mellitus and lipids). Results: Of 8602 participants at risk at baseline, 3580 (41.6%) developed abnormal blood glucose during an average of 4.9 years follow-up. The average eCRF of 12.03 ± 1.75 METs was equivalent to the CRF of 12.15 ± 2.40 METs within the 10% equivalence limit. In fully adjusted models, the estimated risks were the same (HRs = 0.96), eCRF (95% CIs = 0.93−0.99), and CRF (95% CI of 0.94−0.98). Each 1-MET increase was associated with a 4% reduced risk. Conclusions: Higher eCRF is associated with a lower risk of abnormal glucose. eCRF can be a vital sign used for research and prevention.

Introduction: The ActiGraph (AG) accelerometer is widely used to assess physical activity (PA) in heart failure (HF) patients. However, the validity of the AG in this population remains unexplored. Objective: Therefore, this study examined the criterion validity of the AG-GT9X for measuring step counts (SC) and energy expenditure (EE) among HF patients. Methods: 16 patients with HF with preserved ejection fraction (mean age = 60.3±12.1yrs) completed a total of 41 symptom-limited cardiopulmonary exercise tests on a treadmill across multiple time points (median (IQR) = 2.5 (1.5–3.5)). All participants wore the AG (model: GT9X) on both the right ankle and waist locations during the test. Manually counted steps and indirect calorimetry-derived EE served as criterion measures. AG-derived EE was estimated using six different prediction equations previously developed for waist-worn AG. AG-derived measurements were compared with criterion measurements by calculating correlation coefficients, equivalence tests with two one-sided tests, mean absolute percentage error (MAPE), percentage bias, and Bland-Altman plots using mixed models to account for the nested nature of repeated measures within subjects. Results: Ankle-worn AG-SC was significantly equivalent to the criterion (p < .05) and had lower MAPE (<10%) compared to the waist location, regardless of PA intensity level. Sasaki-EE was significantly equivalent to the criterion (p < .05), with the lowest percentage bias overall (0.7%). Conclusions: The ankle-worn AG-SC and Sasaki-EE showed better accuracy among HF patients in laboratory settings. Further research is warranted to cross-validate the results in different settings.

Sufficient daily physical activity is associated with many positive mental, physical, and societal benefits in children. Unfortunately, most children worldwide do not achieve recommended levels of daily physical activity (PA), and a majority of evidence is from Western countries and based on subjective measures. This study examined the prevalence and correlates of objectively measured PA levels among Omani children in 2017 (pre-pandemic). A two-stage cluster sampling was used to recruit the 4th grade children across five regions of Oman. A final analytic sample included 1053 children (504 boys, 549 girls) with a mean age of 9.21 years old. PA was objectively measured using a wrist-worn Polar Active Watch during three consecutive school days. Screen-based sedentary behaviors and other PA-related behaviors were subjectively measured. On average, boys were less sedentary and more active, with a greater likelihood of meeting current recommendations when compared with girls. The self-reported time spent in screen-based sedentary behaviors was relatively low for both boys and girls and was not associated with PA; however, sports team participation was associated with a greater likelihood of meeting the current recommendation. The present study provides empirical data on objectively measured PA in Omani children. The gender disparities concerning daily PA, including sports team participation, should receive further attention.

Metabolic carts are commonly used to estimate oxygen consumption (V̇O₂) during exercise, but are largely limited to controlled laboratory settings. The V̇O₂ Master Pro (VMP) is a newer, portable metabolic analyzer designed to address this limitation; however, few studies have evaluated the validity of this device at varying activity levels. This study aimed to assess the validity of the VMP in measuring V̇O₂ compared with a stationary metabolic cart, the COSMED Quark CPET (CQ), during sedentary activity and treadmill walking/jogging in a laboratory setting. Twenty-seven healthy adults (mean age = 22.1 ± 7.6 years; female = 51.8%) participated in two laboratory trials on separate days. In a counterbalanced order, participants used the CQ and VMP during 10 min conditions of the following activities: sedentary activity (sitting quietly), slow walking (3.2 km/h), brisk walking (5.6 km/h), and jogging (7.2 km/h). The agreement between the two measures was evaluated using equivalence testing, mean absolute percentage error (MAPE), percentage bias, intraclass correlation coefficients (ICCs), and Bland–Altman analyses. The devices showed low agreement and significant proportional biases across all activity levels (ICCs = 0.135–0.323). Equivalence testing did not demonstrate statistically significant equivalence between the devices ( p > 0.05), with the VMP underestimating V̇O₂. The smallest error appeared during jogging (MAPE = 20.05%; percentage bias= −19.29%). The VMP underestimated V̇O₂ at all tested intensities, demonstrating low accuracy and agreement relative to the reference measure. This may be attributed to limited ventilatory flow capture or sensor responsiveness during submaximal activities. Observed bias and within-subject variability suggest caution when using the VMP across different submaximal activity levels.