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International Journal of Sports Medicine Mar 2023Baroreflex sensitivity (BRS) is a measure of cardiovagal baroreflex and is lower in normobaric and hypobaric hypoxia compared to normobaric normoxia. The aim of this...
Baroreflex sensitivity (BRS) is a measure of cardiovagal baroreflex and is lower in normobaric and hypobaric hypoxia compared to normobaric normoxia. The aim of this study was to assess the effects of hypobaria on BRS in normoxia and hypoxia. Continuous blood pressure and ventilation were recorded in eighteen seated participants in normobaric normoxia (NNx), hypobaric normoxia (HNx), normobaric hypoxia (NHx) and hypobaric hypoxia (HHx). Barometric pressure was matched between NNx vs. NHx (723±4 mmHg) and HNx vs. HHx (406±4 vs. 403±5 mmHg). Inspired oxygen pressure (PiO) was matched between NNx vs. HNx (141.2±0.8 vs. 141.5±1.5 mmHg) and NHx vs. HHx (75.7±0.4 vs. 74.3±1.0 mmHg). BRS was assessed using the sequence method. BRS significantly decreased in HNx, NHx and HHx compared to NNx. Heart rate, mean systolic and diastolic blood pressures did not differ between conditions. There was the specific effect of hypobaria on BRS in normoxia (BRS was lower in HNx than in NNx). The hypoxic and hypobaric effects do not add to each other resulting in comparable BRS decreases in HNx, NHx and HHx. BRS decrease under low barometric pressure requires future studies independently controlling O and CO to identify central and peripheral chemoreceptors' roles.
Topics: Humans; Baroreflex; Hypoxia; Atmospheric Pressure; Lung; Oxygen; Heart Rate
PubMed: 36455595
DOI: 10.1055/a-1960-3407 -
International Journal of Environmental... Nov 2022The aims of this study were to (i) verify the relationship between reserve oxygen uptake (VO) and reserve heart rate (HR) in young male tennis players, and (ii)...
The aims of this study were to (i) verify the relationship between reserve oxygen uptake (VO) and reserve heart rate (HR) in young male tennis players, and (ii) understand the relationship between oxygen uptake (VO) measured at the end of a tennis drill and recovery heart rate (HR) after the tennis drill. Ten young male tennis players (16.64 ± 1.69 years; 62.36 ± 6.53 kg of body mass; 175.91 ± 5.26 cm of height) were recruited from the National Tennis Association. Players were instructed to perform a tennis drill based on an incremental intensity protocol. Afterward, three levels of intensity were used based on VO and HR. A significant variance was observed between levels (VO and HR = < 0.001). VO presented a significant and high agreement with HR. The mean data revealed non-significant differences ( > 0.05), a very high relationship of linear regression (R = 82.4%, < 0.001), and high agreement in Bland Altman plots. VO at the highest level of intensity (>93%), presented a significant correlation with HR during the immediate 30 s after the drill (r = 0.468, = 0.028). Tennis coaches or instructors must be aware of the differences between monitoring or prescribing training intensities based on HR or HR. They can also use HR for 30 s immediately after exercise to verify and understand the variation in their players' cardiorespiratory capacities.
Topics: Male; Humans; Heart Rate; Tennis; Physical Fitness; Exercise Test; Oxygen
PubMed: 36497853
DOI: 10.3390/ijerph192315780 -
American Journal of Physiology.... Nov 2022Developmental oxygen is a powerful stressor that can induce morphological and functional changes in the cardiovascular systems of embryonic and juvenile vertebrates....
Developmental oxygen is a powerful stressor that can induce morphological and functional changes in the cardiovascular systems of embryonic and juvenile vertebrates. This plasticity has been ascribed, at least in part, to the unique status of the developing cardiovascular system, which undergoes organogenesis while meeting the tissue oxygen demands of the embryo. We have previously reported an array of functional and morphological changes in embryonic American alligators that persist into juvenile life. Most notably, cardiac enlargement as well as functional parameters of anesthetized juvenile alligators remains after embryonic hypoxic exposure. Because the effects of developmental oxygen in crocodilians have only been investigated in anesthetized animals, we explored the pressure dynamics of both ventricles as well as systemic pressure in response to stressors of acute hypoxia and swimming. Our current findings demonstrate that developmental programming of cardiac function (intraventricular pressure and heart rate) does persist into juvenile life, but it is chamber-specific and depends on the experimental manipulation. Acute hypoxic exposure revealed that juvenile alligators that had experienced 10% O as embryos maintain right ventricle function and increase left ventricle function during exposure. Finally, the data indicate blood flow in the left aorta must originate from the left ventricle during acute hypoxia and swimming.
Topics: Animals; Alligators and Crocodiles; Oxygen; Hypoxia; Heart Rate; Ventricular Function
PubMed: 36121144
DOI: 10.1152/ajpregu.00059.2022 -
Annual International Conference of the... Jul 2018This paper presents a comparison between finger and neck photoplethysmography (PPG) in order to assess the potential and limitations of this, non-conventionally used,...
This paper presents a comparison between finger and neck photoplethysmography (PPG) in order to assess the potential and limitations of this, non-conventionally used, body site for application in pulse oximetry. PPG signals were recorded at both sites from healthy subjects to inspect the differences in average waveforms, as well as in oxygen saturation (SpO) and heart rate (HR) estimation. The results show significant differences in the average PPG pulse waveforms for different contour features such as diastolic or dicrotic notch amplitude, among others. The results show that the HR estimated from signals obtained with the neck sensor are strongly correlated to the output of the reference finger (R=0.862, MAE=1.27 BPM), whereas SpO measurements are not that accurately predicted (R=0.129, MAE=11.7%). Spectrograms under different breathing conditions revealed that the respiratory frequency is more predominant in neck PPG than in finger, which has a great potential for respiratory rate (RR) extraction. These are very promising results for the suitability of the neck as an alternative location for monitoring of respiratory diseases, and specifically for sleep apnea.
Topics: Heart Rate; Oximetry; Oxygen; Photoplethysmography; Respiratory Rate
PubMed: 30441318
DOI: 10.1109/EMBC.2018.8513247 -
Pediatrics and Neonatology Jun 2016Different studies have shown that the use of olfactory stimuli during painful medical procedures reduces infants' response to pain. The main purpose of the current study...
BACKGROUND
Different studies have shown that the use of olfactory stimuli during painful medical procedures reduces infants' response to pain. The main purpose of the current study was to investigate the effect of breast milk odor and vanilla odor on premature infants' vital signs including heart rate and blood oxygen saturation during and after venipuncture.
METHODS
A total of 135 preterm infants were randomly selected and divided into three groups of control, vanilla odor, and breast milk odor. Infants in the breast milk group and the vanilla group were exposed to breast milk odor and vanilla odor from 5 minutes prior to sampling until 30 seconds after sampling.
RESULTS
The results showed that breast milk odor has a significant effect on the changes of neonatal heart rate and blood oxygen saturation during and after venipuncture and decreased the variability of premature infants' heart rate and blood oxygen saturation. Vanilla odor has no significant effect on premature infants' heart rate and blood oxygen saturation.
CONCLUSION
Breast milk odor can decrease the variability of premature infants' heart rate and blood oxygen saturation during and after venipuncture.
Topics: Female; Heart Rate; Humans; Infant, Newborn; Infant, Premature; Male; Milk, Human; Odorants; Oxygen; Phlebotomy; Vanilla
PubMed: 26560183
DOI: 10.1016/j.pedneo.2015.09.004 -
Canadian Journal of Veterinary Research... Jul 2020Recumbency affects respiratory mechanics and oxygenation in anesthetized horses. Changes in pleural and abdominal pressures that can impair ventilation have not been...
Recumbency affects respiratory mechanics and oxygenation in anesthetized horses. Changes in pleural and abdominal pressures that can impair ventilation have not been described in all recumbencies. The objective of this study was to determine the effects of patient positioning on transdiaphragmatic pressure and selected hemodynamic variables. Horses were maintained under total intravenous general anesthesia with nasal oxygen supplementation. Transnasal balloon catheters in the stomach and thoracic esophagus were used to measure intrathoracic and gastric pressures in standing horses and in anesthetized horses positioned in right and left lateral recumbency, dorsal recumbency, reverse Trendelenburg position, and Trendelenburg position. Transdiaphragmatic pressure was calculated as the difference between gastric and intrathoracic pressures. Measurements of oxygen saturation (SpO), heart rate, systolic, diastolic and mean arterial pressures, and respiratory rate were obtained every 5 minutes. When compared to dorsal recumbency, gastric expiratory pressure is decreased in the standing position. Thoracic expiratory pressure is decreased in standing and reverse Trendelenburg. Transdiaphragmatic expiratory pressure and SpO are decreased in Trendelenburg. Heart rate is increased in reverse Trendelenburg. Systolic, diastolic, and mean arterial pressures are decreased in reverse Trendelenburg and increased in left lateral and right lateral recumbency. We found that there is wide variation in respiratory pressures between horses and positions and they are not predictive of associated changes in hemodynamic variables.
Topics: Anesthesia, General; Anesthetics, Intravenous; Animals; Body Weight; Diaphragm; Female; Heart Rate; Hemodynamics; Horses; Male; Oxygen; Pressure
PubMed: 32801455
DOI: No ID Found -
Journal of Applied Physiology... Jul 2009Divers and hyperbaric chamber attendants breathe hyperbaric air routinely. Hyperbaric oxygen (HBO(2)) is used therapeutically frequently. Although much is understood...
Divers and hyperbaric chamber attendants breathe hyperbaric air routinely. Hyperbaric oxygen (HBO(2)) is used therapeutically frequently. Although much is understood about the hemodynamic physiology and gas exchange effects during hyperbaric air and HBO(2) exposure, arterial and pulmonary arterial (PA) catheter data, including blood gas values during hyperbaric air and HBO(2) exposure of normal humans, have not been reported. We exposed 10 healthy volunteers instrumented with arterial and PA catheters to air at 0.85, 3.0, 2.5, 2.0, 1.3 (decompression stop), 1.12 (decompression stop), and 0.85 atm abs (our altitude) and then at identical pressures breathing O(2) followed by atmospheric pressure air while we measured arterial and PA pressures (PAP), cardiac output (Q), and blood gas measurements from both arterial and PA catheters. Although hemodynamic changes occurred during exposure to both hyperbaric air and HBO(2), we observed a greater magnitude of change under HBO(2) conditions: heart rate changes ranged from -9 to -19% (air to O(2)), respiratory rate from -12 to -17%, Q from -7 to -18%, PAP from -18 to -19%, pulmonary vascular resistance from -38 to -48%, and right-to-left shunt fraction from -87 to -107%. Mixed venous CO(2) fell 8% from baseline during HBO(2) despite mixed venous O(2) tensions of several hundred Torr. The stroke volume, O(2) delivery, and O(2) consumption did not change across exposures. The arterial and mixed venous partial pressures of O(2) and contents were elevated, as predicted. O(2) extraction increased 37% during HBO(2).
Topics: Adolescent; Adult; Blood Gas Analysis; Blood Pressure; Female; Heart Rate; Hemodynamics; Humans; Hyperbaric Oxygenation; Male; Oxygen; Oxygen Consumption; Pulmonary Artery; Young Adult
PubMed: 19407250
DOI: 10.1152/japplphysiol.91012.2008 -
Scientific Reports Sep 2023Predicting cardiorespiratory fitness levels can be useful for measuring progress in an exercise program as well as for stratifying cardiovascular risk in asymptomatic...
Predicting cardiorespiratory fitness levels can be useful for measuring progress in an exercise program as well as for stratifying cardiovascular risk in asymptomatic adults. This study proposes a model to predict fitness level in terms of maximal oxygen uptake using anthropometric, heart rate, and step count data. The model was trained on a diverse cohort of 3115 healthy subjects (1035 women and 2080 men) aged 42 ± 10.6 years and tested on a cohort of 779 healthy subjects (260 women and 519 men) aged 42 ± 10.18 years. The developed model is capable of making accurate and reliable predictions with the average test set error of 3.946 ml/kg/min. The maximal oxygen uptake labels were obtained using wearable devices (Apple Watch and Garmin) during recorded workout sessions. Additionally, the model was validated on a sample of 10 subjects with maximal oxygen uptake determined directly using a treadmill protocol in a laboratory setting and showed an error of 4.982 ml/kg/min. Unlike most other models, which use accelerometer readings as additional input data, the proposed model relies solely on heart rate and step counts-data readily available on the majority of fitness trackers. The proposed model provides a point estimation and a probabilistic prediction of cardiorespiratory fitness level, thus it can estimate the prediction's uncertainty and construct confidence intervals.
Topics: Adult; Male; Humans; Female; Cardiorespiratory Fitness; Heart Rate; Anthropometry; Exercise; Oxygen
PubMed: 37737296
DOI: 10.1038/s41598-023-43024-x -
BMJ Open Respiratory Research Sep 2020A simple and efficient exercise test possible in a small space is welcome to supplement 6 min walk test (6MWT) that demands a 100 feet corridor to perform. (Comparative Study)
Comparative Study
BACKGROUND
A simple and efficient exercise test possible in a small space is welcome to supplement 6 min walk test (6MWT) that demands a 100 feet corridor to perform.
METHODS
The proposed two chair test (2CT) makes a person to sit and move five times between two chairs placed face to face at 5 feet apart and note the changes in pulse-rate (PR) and arterial oxygen saturation (SpO) at every 10 s for 2 min after that. Comparison of the post-exercise measurements (PR and SpO) with a repeat performance in same patients was done for reproducibility and doing the same after 6MWT and 2CT in another set of patients was meant for for acceptability. The statistical analysis was made on moment to moment change, mean maximal difference and mean cumulative difference for the measurements using p value, z-score, r value and principal component analysis (PCA).
FINDINGS
A total of 40 and 60 volunteers were included for testing reproducibility and acceptability. On both the sets, the difference in most of comparisons between the measured variable (PR and SpO) showed the p values remaining insignificant (>0.05), and z-score being <1 SD of the corresponding other and the correlation coefficients (r) remaining excellent (>0.9). Furthermore, the PCA shows complete overlapping. The post-exercise changes did not corelate the walking distance in 6MWT.
INTERPRETATION
The proposed 2CT demands small space and appears reproducible and comparable with 6MWT in terms of its post-exercise impact on PR and SpO. This novel test also appears more of cardiopulmonary reserve specific.
Topics: Aged; Exercise Test; Exercise Tolerance; Female; Healthy Volunteers; Humans; Male; Middle Aged; Oxygen; Predictive Value of Tests; Pulse; Reproducibility of Results; Walk Test
PubMed: 32963026
DOI: 10.1136/bmjresp-2019-000447 -
PLoS Computational Biology Jun 2017Lipids are main fuels for cellular energy and mitochondria their major oxidation site. Yet unknown is to what extent the fuel role of lipids is influenced by their...
Lipids are main fuels for cellular energy and mitochondria their major oxidation site. Yet unknown is to what extent the fuel role of lipids is influenced by their uncoupling effects, and how this affects mitochondrial energetics, redox balance and the emission of reactive oxygen species (ROS). Employing a combined experimental-computational approach, we comparatively analyze β-oxidation of palmitoyl CoA (PCoA) in isolated heart mitochondria from Sham and streptozotocin (STZ)-induced type 1 diabetic (T1DM) guinea pigs (GPs). Parallel high throughput measurements of the rates of oxygen consumption (VO2) and hydrogen peroxide (H2O2) emission as a function of PCoA concentration, in the presence of L-carnitine and malate, were performed. We found that PCoA concentration < 200 nmol/mg mito protein resulted in low H2O2 emission flux, increasing thereafter in Sham and T1DM GPs under both states 4 and 3 respiration with diabetic mitochondria releasing higher amounts of ROS. Respiratory uncoupling and ROS excess occurred at PCoA > 600 nmol/mg mito prot, in both control and diabetic animals. Also, for the first time, we show that an integrated two compartment mitochondrial model of β-oxidation of long-chain fatty acids and main energy-redox processes is able to simulate the relationship between VO2 and H2O2 emission as a function of lipid concentration. Model and experimental results indicate that PCoA oxidation and its concentration-dependent uncoupling effect, together with a partial lipid-dependent decrease in the rate of superoxide generation, modulate H2O2 emission as a function of VO2. Results indicate that keeping low levels of intracellular lipid is crucial for mitochondria and cells to maintain ROS within physiological levels compatible with signaling and reliable energy supply.
Topics: Animals; Cell Respiration; Cells, Cultured; Computer Simulation; Diabetes Mellitus; Electron Transport; Guinea Pigs; Hydrogen Peroxide; Lipid Metabolism; Male; Metabolism; Mitochondria, Heart; Models, Cardiovascular; Oxidation-Reduction; Oxygen; Palmitoyl Coenzyme A; Reactive Oxygen Species
PubMed: 28598967
DOI: 10.1371/journal.pcbi.1005588