Humans ; Child ; Cardiovascular Diseases/diagnosis* ; Exercise Test ; Oxygen Consumption

Objective: To investigate the correlation between heart rate index (HRI), systolic blood pressure(SBP) peak-to-SBPrest ratio (SBPR) and peak oxygen consumption (peakVO₂) in patients with chronic heart failure (CHF), and discuss the possibility of using HRI and SBPR collected during exercise to assess the exercise tolerance of CHF patients in the absence of gas analysis. Methods: In this cross-sectional study, a total of 547 patients with CHF who underwent cardiopulmonary exercise test(CPET) in Tongji Hospital Heart Rehabilitation Center Affiliated to Tongji University from March 2007 to December 2018 were collected retrospectively, focusing on their clinical data including age, gender, type of heart failure,BMI as well as data collected during their CPETs, such as peakVO₂, HRI and SBPR. Spearman univariate correlation analysis was used for statistical analysis, to unveil the correlations between peakVO₂ and those parameters, and multiple linear regression analysis was also conducted. Results: A total of 547 CHF patients conducting CPET were included in this research, of which 447 were male, at age of 63(56, 69). Univariate analysis indicates that HRI, SBPR and peakVO₂ showed significant positive correlation (r=0.323, 0.263, respectively, all P<0.001); Age and peak VO₂ showed significant negative correlation(r=-0.207, P<0.001); Male patients showed peakVO₂ higher than female(r=-0.229, P<0.001); PeakVO₂ of heart failure with reduced ejection fraction(HFrEF) was lower than heart failure with mid-range ejection fraction(HFmrEF)and heart failure with preserved ejection fraction(HFpEF) (r=0.181, P<0.001). Body mass index (BMI) had no significant correlation with peakVO₂ (P>0.05). Multivariate linear regression analysis showed that the HRI, SBPR were positively correlated with peakVO₂(t=7.68, 5.08, respectively, all P<0.05), while age and BMI showed negative correlation with peakVO₂(t=-5.43, -0.31, respectively, all P<0.05). PeakVO₂ of male was higher than female(t=-6.03, P<0.05), and peakVO₂ of HFrEF was lower than those of HFmrEF and HFpEF(t=3.17, 4.48, respectively, all P<0.05). A linear equation (F=33.52, adjusted R²=0.29) could be constructed: peakVO₂=10.65(male) or 8.53(female)+4.26HRI+3.31SBPR-0.07age-0.13BMI+0(HFrEF) or 1.05 (HFmrEF) or 1.62(HFpEF). Conclusion: HRI and SBPR are positively correlated with peakVO₂. In the absence of gas analysis, it is possible to apply HRI and SBPR during exercise to predict exercise tolerance in patients with CHF.
Chronic Disease ; Cross-Sectional Studies ; Female ; Heart Failure ; Heart Rate ; Humans ; Male ; Oxygen Consumption/physiology* ; Prognosis ; Retrospective Studies ; Stroke Volume/physiology*

Objective: To investigate the postoperative cardiopulmonary fitness of children with congenital heart diseases (CHD). Methods: This is a retrospective study. A total of 136 children after cardiac correction undergoing cardiopulmonary exercise test (CPET) in Shanghai Children's Medical Center from March 1 to June 30, 2021 were selected. According to the surgical procedure, the children were divided into two groups: the biventricular correction group (BV group) (n=75) and single ventricular correction group (SV group) (n=61). The BV group was divided into two subgroups: simple congenital heart disease (S-CHD) group (n=35) and complex congenital heart disease (C-CHD) group (n=40). CPET parameters, including VO₂ max, VO₂/kg max, VO₂/kg@AT, O₂/HR max, HRR, PetCO₂ max, CI, HRR at 1 min, VE/VCO₂ slope, OUES/kg and EOV, were analyzed. CPET parameters of patients underwent different procedure were compared. In the subgroup analysis, CPET parameters of patients in S-CHD group and C-CHD group were compared. The parameters of the BV group were compared with the normal value. Linear correlation analysis was used to identify the correlation between the CPET parameters. Results: A total of 136 children with CHD after surgery were enrolled. The age was (9.4±3.1) (ranged 6.2-16.0) years, and there was 84 (61.8%) male. All the children completed CPET examination safely without experiencing serious circulation abnormalities. Compared with the SV group, the VO₂/kg max ((32.6±6.9) ml·kg^-1·min^-1 vs. (23.5±5.9) ml·kg^-1·min^-1, P<0.001), O₂/HR max ((7.24±2.93) ml/beat vs. (6.35±2.17)ml/beat, P=0.030), HRR at 1 min ((32.5±13.9) beat/min vs. (26.3±12.5) beat/min, P=0.036), OUES/kg (36.9±8.8 vs. 29.7±11.8, P=0.001) were significantly higher, VE/VCO₂ slope (29.1±5.20 vs. 35.1±8.0, P<0.001) and incidence of EOV (32.0%(24/75) vs. 57.4%(31/61), P=0.027) were significantly lower in BV group. Compared with the simple CHD subgroup, VE/VCO₂ slope and the incidence of EOV were higher, VO₂/kg max, O₂/HR max, HRR at 1 min and OUES/kg were lower in the complex CHD subgroup (all P<0.05). Cardiopulmonary function parameters of the BV group were lower than the normal value. Linear correlation analysis showed that VO₂/kg@AT was strongly correlated with VO₂/kg max (r=0.86, P<0.001), VO₂/kg max was strongly correlated with OUES/kg (r=0.63, P<0.001), HRR was strongly correlated with CI (r=0.91, P<0.001), and VO₂/kg max was strongly correlated with OUES/kg (r=0.63, P<0.001). VE/VCO₂ slope was strongly correlated with PetCO₂ max (r=1.00, P<0.001). Conclusions: The exercise cardiopulmonary function of children after single ventricular correction is weaker than that of biventricular correction, and the exercise tolerance of children after biventricular correction is lower than that of normal children. Among the children after biventricular correction, the exercise tolerance of children with complex CHD is lower than that of children with simple CHD. Postoperative CPET is of important realistic significance for CHD children.
Adolescent ; Child ; China ; Exercise Test/methods* ; Female ; Heart Defects, Congenital/surgery* ; Humans ; Male ; Oxygen Consumption ; Retrospective Studies

A high-precision human metabolic measurement system is designed. The system uses STM32F103 as the main control chip to acquire oxygen, carbon dioxide and flow signals to calculate four quantitative indicators: oxygen consumption(V_O2), carbon dioxide production(V_CO2), respiratory entropy(RQ) and resting energy metabolism(REE), and finally uses an upper computer to display the calculation results.In this paper, the signal acquisition circuit design was carried out for the oxygen sensor, carbon dioxide sensor and flow sensor, and the validity of the device was verified with the American machine MGCDiagnositcs using Bland-Altman analysis method, and the results showed that the four parameters of V_O2,V_CO2, RQ and REE of both devices fell in the agreement interval of more than 95%. The device thus provides accurate metabolic measurements and offers an effective tool for the field of general health and clinical nutrition support in China.
Calorimetry, Indirect ; Carbon Dioxide/metabolism* ; Energy Metabolism ; Humans ; Oxygen ; Oxygen Consumption

OBJECTIVE: This study evaluated the effect of maximal oxygen pulse (O ₂P _max) on patients with chronic obstructive pulmonary disease (COPD) and confirmed the predictive effect on acute exacerbations of COPD (AECOPD). METHODS: This retrospective study included 91 participants who underwent cardiopulmonary exercise testing (CPET), lung function testing, a dyspnea scale assessment, and a 3-year follow-up. The participants were divided into two groups according to the O ₂P _max value. Exercise capacity, ventilatory conditions, gas exchange efficiency, and dyspnea symptoms were compared, and the correlations between O ₂P _max and these indices were evaluated. The ability of O ₂P _max to predict AECOPD was examined. RESULTS: Exercise capacity, ventilatory conditions, and gas exchange efficiency were lower, and dyspnea symptom scores were higher in the impaired O ₂P _max group ( P < 0.05). O ₂P _max was positively correlated with forced vital capacity (FVC)%, forced expiratory volume in 1 sec (FEV ₁)%, FEV ₁/FVC%, anaerobic threshold (AT), work rate (WR)%, aximal oxygen uptake (V̇O _2max)%, V̇O ₂/kg _max, V̇O ₂/kg _max%, WR _AT, WR _max, V̇O _2AT, V̇O _2max, and V̇ _Emax, and was negatively correlated with EqCO _2AT, and EqCO _2max ( P < 0.05). Most importantly, O ₂P _max could be used to predict AECOPD, and the best cut-off value was 89.5% (area under the curve, 0.739; 95% CI, 0.609-0.869). CONCLUSION O ₂P _max reflected exercise capacity, ventilation capacity, gas exchange capacity, and dyspnea symptoms in patients with COPD and may be an independent predictor of AECOPD.
Dyspnea/etiology* ; Exercise Tolerance ; Humans ; Oxygen ; Oxygen Consumption ; Pulmonary Disease, Chronic Obstructive ; Retrospective Studies

Objective: The aim of this study was to investigate scuba diving induced exercise response in novice divers as required in open water scuba diving certification. Methods: Maximal cardiopulmonary exercise test (CPET) was performed in 30 novice divers before and within 24 hours after a standard scuba diving open water certification diving protocol of four open water dives. Results: A significant increase in maximal oxygen consumption (VO2max) in mL·kg-1·min-1 after scuba diving training [25.84 (6.0) vs. 27.04 (7.0)] (p<0.05) suggestive of an increase in exercise performance. Ventilatory drive (VE/VCO2) also showed a significant increase 27.95 (2.7) vs. 30.07 (5.3). Ventilatory anaerobic threshold (VAT), blood pressure and lung function parameters showed no significant differences with open water scuba diving certification training. Conclusion In novice divers, repeated training exposure during open water scuba diving certification results in increased cardiorespiratory fitness. Although further corroborating studies are needed, this would suggest that recreational scuba diving may be an option for exercise promotion in the future.
Diving ; Diving and Hyperbaric Medicine ; Oxygen Consumption ; Exercise

Objective: To investigate the effects of ticagrelor on cardiorespiratory fitness in patients with coronary heart disease after percutaneous coronary intervention (PCI). Methods: A total of 1 073 patients, who were diagnosed as coronary heart disease and underwent cardiopulmonary exercise testing (CPET) within 1 year after PCI, were enrolled from September 2017 to September 2019 in Peking University Third Hospital, including 309 patients in ticagrelor group and 764 patients in clopidogrel group. Clinical information, blood test results, echocardiographic parameters, cardiorespiratory fitness related parameters (including peak oxygen uptake (VO(2)), anaerobic threshold VO(2), peak oxygen pulse (VO(2)/HR) and carbon dioxide ventilation equivalent (VE/VCO(2)) slope), coronary lesions and intervention information were obtained. Cardiopulmonary fitness related indexes were compared between the two groups, and the correlation between ticagrelor use and cardiopulmonary fitness related indexes was analyzed by multivariate logistic regression. Patients who underwent CPET within 1 month after PCI were included in the subgroup analysis. Results: In ticagrelor group, the age was (60.3±10.3) years, and 253(81.9%) cases were male. The age of clopidogrel group was (60.6±10.0) years, and there were 608(79.6%) males. No significant differences were observed in peak VO(2), anaerobic threshold VO(2), and peak VO(2)/HR between the two groups (all P>0.05), but the VE/VCO(2) slope was significantly higher in the ticagrelor group than in the clopidogrel group (30.075 (27.207, 33.603) vs. 28.853 (25.970, 32.336), P<0.001). Logistic regression analysis suggested that the peak VO(2), anaerobic threshold VO(2) and peak VO(2)/HR were not significantly correlated with the ticagrelor use (all P>0.05), while the VE/VCO(2) slope was independently correlated with ticagrelor use (OR=1.098, 95%CI 1.032-1.168, P=0.003). Subgroup analysis of patients who underwent CPET within 1 month after PCI also indicated that no significant difference were observed in peak VO(2), anaerobic threshold VO(2), peak VO(2)/HR and VE/VCO(2) slope between the two groups (all P>0.05). Logistic regression analysis suggested that the peak VO(2), anaerobic threshold VO(2) and peak VO(2)/HR were not significantly correlated with ticagrelor use (all P>0.05), while the VE/VCO(2) slope was significantly correlated with ticagrelor use (OR=1.132, 95%CI 1.030-1.244, P=0.010). Conclusion: Among coronary heart disease patients after PCI, treatment with clopidogrel does not result in significant decrease in exercise endurance as compared with patients treated with ticagrelor.
Aged ; Cardiorespiratory Fitness ; Exercise Test ; Female ; Heart Failure ; Humans ; Male ; Middle Aged ; Oxygen Consumption ; Percutaneous Coronary Intervention ; Ticagrelor

BACKGROUND: Korea has shown a rapid pace of aging and has become an aged society in a shorter period than Western countries. Therefore, it is important that middle-aged workers maintain their ability to work in the industrial field at the maximum level while maintaining their health. The purpose of this study was to analyze the factors affecting work ability and to use this data to maintain the working ability of middle-aged workers in the future.METHODS: From 2015 to 2017, we surveyed 371 street cleaners who visited a health center for health promotion in a metropolitan city. The relationship between the general characteristics of the survey subjects and the Work Ability Index (WAI) was confirmed by a univariate analysis. Statistically significant (p<0.2) factors were selected and a multiple linear regression analysis was conducted with WAI scores as a dependent variable.RESULTS: Age, body mass index, body fat percentage, the Alcohol Use Disorders Identification Test-Korea (AUDIT-K) scores, the Psychosocial Well-Being Index-Short Form (PWI-SF) scores, maximal oxygen consumption (VO(2max)), and hypertension showed statistically significant correlations with the WAI in the univariate analysis. In the multivariate analysis, the VO(2max), AUDIT-K scores, and PWI-SF scores were included in the regression equation. VO(2max) had the greatest effect on the standardization coefficient indicating the relative contribution of independent variables, followed by the AUDIT-K scores and the PWI-SF scores.CONCLUSION: Programs to increase workers’ physical work ability and alleviate psychosocial stress and drinking habits should be developed and implemented in the future.
Adipose Tissue ; Aging ; Body Mass Index ; Drinking ; Health Promotion ; Humans ; Hypertension ; Korea ; Linear Models ; Middle Aged ; Multivariate Analysis ; Oxygen Consumption ; Physical Endurance

Oxygen is required to sustain aerobic organisms. Reactive oxygen species (ROS) are constantly released during mitochondrial oxygen consumption for energy production. Any imbalance between ROS production and its scavenger system induces oxidative stress. Oxidative stress, a critical contributor to tissue damage, is well-known to be associated with various diseases. The kidney is susceptible to hypoxia, and renal hypoxia is a common final pathway to end stage kidney disease, regardless of the underlying cause. Renal hypoxia aggravates oxidative stress, and elevated oxidative stress, in turn, exacerbates renal hypoxia. Oxidative stress is also enhanced in chronic kidney disease, especially diabetic kidney disease, through various mechanisms. Thus, the vicious cycle between oxidative stress and renal hypoxia critically contributes to the progression of renal injury. This review examines recent evidence connecting chronic hypoxia and oxidative stress in renal disease and subsequently describes several promising therapeutic approaches against oxidative stress.
Anoxia ; Diabetic Nephropathies ; Kidney ; Kidney Failure, Chronic ; Oxidative Stress ; Oxygen ; Oxygen Consumption ; Reactive Oxygen Species ; Renal Insufficiency, Chronic

The increasing prevalence of inactivity and obesity, along with aging, has implications on work capacity of labor force. This study reports the relationships between activity level and BMI by age with objectively measured physical workload. Data were examined from a sample of 19 481 Finnish employees using an estimate of minute-to-minute oxygen consumption based on R-R interval recordings. The mean estimated %VO₂max during the working day was 12.1 (±3.6) and 15.1 (±4.5)% for men and women, respectively. Based on a linear model, the mean %VO₂max increased by 1.5%-unit per 10-year increase in age, by 2.1%-unit per 5 kg/m² increase in BMI, and decreased by 1.6%-unit if improving physical activity class by two (p < 0.001 for all). Overweight and obesity, together with inactivity, notably increases workload throughout the career, even though at young adulthood, the daily workload is almost the same for each person regardless of the BMI, activity level, or gender. This study highlights the importance of regular physical activity and normal weight in protecting the worker from excessive physical (cardiovascular) workload during the whole working career.
Aging ; Body Mass Index ; Employment ; Female ; Humans ; Linear Models ; Male ; Motor Activity ; Obesity ; Overweight ; Oxygen Consumption ; Prevalence