-
Sensors (Basel, Switzerland) Feb 2023Oxygen uptake (V˙O2) is an important metric in any exercise test including walking and running. It can be measured using portable spirometers or metabolic analyzers....
Oxygen uptake (V˙O2) is an important metric in any exercise test including walking and running. It can be measured using portable spirometers or metabolic analyzers. Those devices are, however, not suitable for constant use by consumers due to their costs, difficulty of operation and their intervening in the physical integrity of their users. Therefore, it is important to develop approaches for the indirect estimation of V˙O2-based measurements of motion parameters, heart rate data and application-specific measurements from consumer-grade sensors. Typically, these approaches are based on linear regression models or neural networks. This study investigates how motion data contribute to V˙O2 estimation accuracy during unconstrained running and walking. The results suggest that a long short term memory (LSTM) neural network can predict oxygen consumption with an accuracy of 2.49 mL/min/kg (95% limits of agreement) based only on speed, speed change, cadence and vertical oscillation measurements from an inertial navigation system combined with a Global Positioning System (INS/GPS) device developed by our group, worn on the torso. Combining motion data and heart rate data can significantly improve the V˙O2 estimation resulting in approximately 1.7-1.9 times smaller prediction errors than using only motion or heart rate data.
Topics: Exercise Test; Heart Rate; Linear Models; Neural Networks, Computer; Oxygen
PubMed: 36850848
DOI: 10.3390/s23042249 -
International Journal of Environmental... Oct 2019The purpose of this study was to evaluate the lifting capabilities of individuals in hypoxia when they wear different types of safety shoes and to investigate the...
OBJECTIVE
The purpose of this study was to evaluate the lifting capabilities of individuals in hypoxia when they wear different types of safety shoes and to investigate the behavior of the physiological responses induced by the lifting process associated with those variables.
METHODS
An experimental design was used, based on two sessions. The first was training and acclimatization session, then an experimental lifting phase. A total of ten male students of King Saud University were recruited in the study. A four-way repeated measures design, with four independent variables and six dependent variables, was used in this research. The independent variables that were studied in the experimental lifting phase were: ambient oxygen content (15%, 18%, and 21%), safety shoes type (light-duty, medium-duty, and heavy-duty), lifting frequency (1 and 4 lifts/min), and replication (first and second trials). The dependent variables were also: maximum acceptable weights lifting using the psychophysical technique, heart rate (HR), electromyography (EMG) of (biceps brachii, trapezius, anterior deltoid, and erector spinae), safety shoes discomfort rating, rating of perceived exertion, and ambient oxygen discomfort rating.
RESULTS
The maximum acceptable weights lifting that were selected by participants at lower levels of the independent variables (ambient oxygen content 21%, lifting frequency 1 lift/min, and first replication) were significantly higher than at high levels of the independent variables (ambient oxygen content 15%, lifting frequency 4 lift/min, and second replication). Several interaction effects were also significant.
CONCLUSIONS
It provides evidence that the ambient oxygen content increases the intensity of workload in lifting tasks. It showed that oxygen content affects the psychophysical selection of maximum acceptable weights lifting and the physiological responses represented in muscular activities and heart rate. It suggests that ambient oxygen content must be considered along with the type of safety shoes worn when the lifting task at altitudes occurs.
Topics: Acclimatization; Adult; Air; Electromyography; Healthy Volunteers; Heart Rate; Humans; Hypoxia; Lifting; Male; Muscle, Skeletal; Oxygen; Physical Exertion; Protective Clothing; Psychophysics; Shoes
PubMed: 31671827
DOI: 10.3390/ijerph16214172 -
Anesthesiology Feb 1999Cardiac complications are common during the postoperative period and may be associated with hypoxemia and tachycardia. Preliminary studies in high-risk patients after... (Clinical Trial)
Clinical Trial Randomized Controlled Trial
BACKGROUND
Cardiac complications are common during the postoperative period and may be associated with hypoxemia and tachycardia. Preliminary studies in high-risk patients after operation have shown a possible beneficial effect of oxygen therapy on arterial oxygen saturation and heart rate.
METHODS
The authors studied the effect of oxygen therapy on arterial oxygen saturation and heart rate in 100 consecutive unselected patients randomly and double blindly allocated to receive air or oxygen therapy between the first and fourth day after major abdominal surgery.
RESULTS
The median arterial oxygen saturation rate increased significantly from 96% to 99% (P < 0.0001) and the heart rate decreased significantly from 85 beats/min to 81 beats/min (P < 0.0001) during oxygen supplementation compared with air administered by a binasal catheter. The greatest decrease in heart rate occurred in patients with the lowest oxygen saturation or the highest heart rate values before oxygen supplementation. Overall, 73% of this unselected group of patients responded with decreased heart rate during supplemental oxygen therapy. No significant differences in changes in heart rate after oxygen supplementation were found between patients with or without an epidural catheter or between the postoperative day studied.
CONCLUSION
Postoperative oxygen therapy increased arterial oxygen saturation and decreased heart rate after uncomplicated abdominal surgery in a consecutive unselected group of patients who received routine postoperative care.
Topics: Abdomen; Adult; Aged; Aged, 80 and over; Double-Blind Method; Female; Heart Rate; Humans; Male; Middle Aged; Myocardial Ischemia; Oxygen; Postoperative Complications; Treatment Outcome
PubMed: 9952140
DOI: 10.1097/00000542-199902000-00008 -
Journal of Physiological Anthropology Oct 2022Several factors have been shown to contribute to hypoxic-induced declined in aerobic capacity. In the present study, we investigated the effects of resting hypoxic...
BACKGROUND
Several factors have been shown to contribute to hypoxic-induced declined in aerobic capacity. In the present study, we investigated the effects of resting hypoxic ventilatory and cardiac responses (HVR and HCR) on hypoxic-induced declines in peak oxygen uptake ([Formula: see text]O).
METHODS
Peak oxygen uptakes was measured in normobaric normoxia (room air) and hypoxia (14.1% O) for 10 young healthy men. The resting HVR and HCR were evaluated at multiple steps of hypoxia (1 h at each of 21, 18, 15 and 12% O). Arterial desaturation (ΔSaO) was calculate by the difference between SaO at normoxia-at each level of hypoxia (%). HVR was calculate by differences in pulmonary ventilation between normoxia and each level of hypoxia against ΔSaO (L min % kg). Similarly, HCR was calculated by differences in heart rate between normoxia and each level of hypoxia against ΔSaO (beats min %).
RESULTS
[Formula: see text]O significantly decreased in hypoxia by 21% on average (P < 0.001). HVR was not associated with changes in [Formula: see text]O. ΔSaO from normoxia to 18% or 15% O and HCR between normoxia and 12% O were associated with changes in [Formula: see text]O (P < 0.05, respectively). The most optimal model using multiple linear regression analysis found that ΔHCR at 12% O and ΔSaO at 15% O were explanatory variables (adjusted R = 0.580, P = 0.02).
CONCLUSION
These results suggest that arterial desaturation at moderate hypoxia and heart rate responses at severe hypoxia may account for hypoxic-induced declines in peak aerobic capacity, but ventilatory responses may be unrelated.
Topics: Male; Humans; Oxygen Consumption; Hypoxia; Pulmonary Ventilation; Heart Rate; Oxygen
PubMed: 36280884
DOI: 10.1186/s40101-022-00310-3 -
Journal of Physiological Anthropology Aug 2020Venous compliance decreases with aging and/or physical inactivity, which is thought to be involved partly in the pathogenesis of cardiovascular disease such as...
BACKGROUND
Venous compliance decreases with aging and/or physical inactivity, which is thought to be involved partly in the pathogenesis of cardiovascular disease such as hypertension. This suggests that it is important to maintain high venous compliance from a young age in order to prevent cardiovascular disease. Both nutrient and exercise could play an important role in the improvement and maintenance of vascular health. Indeed, habitual endurance exercise is known to improve the venous compliance, although little is known about the effect of diet on venous compliance. Considering that higher consumption of vegetables could contribute to the arterial vascular health and the decreased blood pressure, it is hypothesized that venous compliance may be greater as vegetable intake is higher. Thus, the purpose of this study was to clarify the association between vegetable intake and venous compliance in healthy young adults.
METHODS
Dietary intake was assessed in 94 subjects (male: n = 44, female: n = 50) using a self-administered diet history questionnaire (DHQ). Intakes of nutrients and food groups that were obtained from the DHQ were adjusted according to total energy intake using the residual method. Based on the adjusted intake of food groups, total vegetable intake was calculated as the sum of green/yellow and white vegetables consumed. Calf volume was measured using venous occlusion plethysmography with a cuff deflation protocol. Calf venous compliance was calculated as the numerical derivative of the cuff pressure-calf volume curve. In addition, circulatory responses (heart rate and systolic and diastolic blood pressure) at resting and maximal oxygen uptake were assessed in all subjects.
RESULTS
Mean value of total vegetables intake was 162.2 ± 98.2 g/day. Simple linear regression analysis showed that greater venous compliance was significantly associated with higher total vegetable consumption (r = 0.260, P = 0.011) and green/yellow vegetable intake (r = 0.351, P = 0.001) but not white vegetable intake (r = 0.013, P = 0.902). These significant associations did not change in the multivariate linear regression models which were adjusted by sex and maximal oxygen uptake.
CONCLUSION
These findings suggest that higher consumption of vegetables, especially of the green/yellow vegetables, may be associated with greater venous compliance in young healthy adults.
Topics: Adult; Blood Pressure; Diet; Female; Heart Rate; Humans; Leg; Male; Oxygen; Regional Blood Flow; Vegetables; Young Adult
PubMed: 32787933
DOI: 10.1186/s40101-020-00231-z -
International Journal of Environmental... Sep 2022Exercise physiologists and coaches prescribe heart rate zones (between 65 and 80% of maximal heart rate, HR) during a marathon because it supposedly represents specific...
Exercise physiologists and coaches prescribe heart rate zones (between 65 and 80% of maximal heart rate, HR) during a marathon because it supposedly represents specific metabolic zones and the percentage of V˙O below the lactate threshold. The present study tested the hypothesis that the heart rate does not reflect the oxygen uptake of recreational runners during a marathon and that this dissociation would be more pronounced in the lower performers' group (>4 h). While wearing a portable gas exchange system, ten male endurance runners performed an incremental test on the road to determine V˙O, HR, and anaerobic threshold. Two weeks later, the same subjects ran a marathon with the same device for measuring the gas exchanges and HR continuously. The %HR remained stable after the 5th km (between 88% and 91%, = 0.27), which was not significantly different from the %HR at the ventilatory threshold (89 ± 4% vs. 93 ± 6%, = 0.12). However, the %V˙O and percentage of the speed associated with V˙O decreased during the marathon (81 ± 5 to 74 ± 5 %V˙O and 72 ± 9 to 58 ± 14 %vV˙O, < 0.0001). Hence, the ratio between %HR and %V˙O increased significantly between the 5th and the 42nd km (from 1.01 to 1.19, = < 0.001). In conclusion, pacing during a marathon according to heart rate zones is not recommended. Rather, learning about the relationship between running sensations during training and racing using RPE is optimal.
Topics: Exercise Test; Heart Rate; Humans; Lactic Acid; Male; Marathon Running; Oxygen; Oxygen Consumption; Physical Endurance
PubMed: 36231750
DOI: 10.3390/ijerph191912451 -
Interactive Cardiovascular and Thoracic... Apr 2014Monitoring and preserving adequate perfusion and oxygen balance is a primary objective of critical care. This prospective observational study aimed to assess the...
OBJECTIVES
Monitoring and preserving adequate perfusion and oxygen balance is a primary objective of critical care. This prospective observational study aimed to assess the relationship between global haemodynamic parameters and variables reflecting tissue oxygenation during the early period following corrective cardiac surgery in neonates and infants. The postoperative time course of oxygen delivery and consumption was evaluated. As surrogate markers of oxygen balance, the central venous oxygen saturation (ScvO2) and venoarterial PCO2 difference (PvaCO2) were thoroughly investigated.
METHODS
Thirteen children <1 year of age who underwent open-heart surgery were prospectively enrolled. In addition to conventional postoperative monitoring, transpulmonary thermodilution (TPTD) was used to monitor cardiac output and calculate oxygen delivery and consumption. In parallel with each TPTD measurement, arterial and central venous blood gas values were recorded. Global haemodynamic parameters and oxygenation measurements were compared with weighted linear regression statistics and Pearson's correlation coefficient.
RESULTS
Data from 145 TPTD measurements and 304 blood gas samples were recorded. The early postoperative period was characterized by a supply-dependent oxygen consumption, as demonstrated by the direct correlation between the change in oxygen delivery and consumption (r = 0.62, P < 0.001). Regarding haemodynamic parameters, none of the heart rate, mean arterial pressure or cardiac index correlated with the measured ScvO2. However, the ScvO2 and PvaCO2 were found to correlate significantly (r = -0.49, P < 0.001), and both strongly related to oxygen extraction.
CONCLUSIONS
Both the ScvO2 and PvaCO2 are reliable and comparable parameters in following tissue oxygen balance during the early postoperative course after open-heart surgery in neonates and infants. As part of multiparameter monitoring, our data highlight the importance of regular ScvO2 measurements and PvaCO2 calculations in paediatric intensive care.
Topics: Arterial Pressure; Biomarkers; Blood Gas Analysis; Cardiac Output; Cardiac Surgical Procedures; Critical Care; Female; Heart Rate; Humans; Infant; Infant, Newborn; Intensive Care Units, Neonatal; Male; Monitoring, Physiologic; Oxygen; Oxygen Consumption; Predictive Value of Tests; Prospective Studies; Reproducibility of Results; Thermodilution; Time Factors; Treatment Outcome
PubMed: 24421206
DOI: 10.1093/icvts/ivt537 -
International Journal of Environmental... Jan 2019The aim was to analyze the effects of cardiorespiratory exercise and air pollution on cognition and cardiovascular markers in four groups of older women: the...
The aim was to analyze the effects of cardiorespiratory exercise and air pollution on cognition and cardiovascular markers in four groups of older women: the active/clean air group (AC), the active/polluted air group (AP), the sedentary/clean air group (SC), and the sedentary/polluted air group (SP). Active groups performed a training task based on progressive walking. Prior to and after the experiment, the following parameters were assessed: cognition, by Mini Mental State Examination (MMSE); maximum oxygen uptake (VO), estimated by the Six-Minute Walk Test (6mWT); heart rate (HR); and oxygen saturation (SpO₂). There were significant differences ( < 0.05) between the AC and the SP in all the MMSE dimensions except "Registration", and in all the physiological variables (VO, SpO₂, HR). Aerobic exercise may be a protective factor against the effects that pollution have on cognition and on the mechanisms of oxygen transport.
Topics: Aged; Air Pollution; Cognition; Environmental Exposure; Exercise; Exercise Test; Female; Heart Rate; Humans; Oxygen; Oxygen Consumption
PubMed: 30654519
DOI: 10.3390/ijerph16020245 -
Revista Chilena de Pediatria Aug 2019The pulse oximeter has been useful in the cardiorespiratory evaluation of the newborn. (Observational Study)
Observational Study
INTRODUCTION
The pulse oximeter has been useful in the cardiorespiratory evaluation of the newborn.
OBJECTIVE
To assess arterial oxygen saturation (SpO2) and heart rate (HR) in newborns in the first 60 minutes after birth.
PATIENTS AND METHOD
Prospective observational study in healthy term newborns, delivered vaginally or by cesarean section, with maternal bonding, carried out at sea level. A continuous post- ductal SpO2 and HR record were obtained from minute 1 to 10 after birth, and then at 15, 30 and 60 minutes. The SpO2 and HR were measured with a Nellcor pulse oximeter. The software Stata v.14 was used for the statistical analysis.
RESULTS
324 healthy term newborns that met the inclusion criteria were included, of which 160 born vaginally and 164 by cesarean section. The SpO2 increased progres sively from minute 1 (58.7%) to minute 10 (94.5%). Newborns delivered vaginally had a significantly higher SpO2 until minute 10 after birth than those born by cesarean section (p < 0.001). In newborns delivered vaginally, HR was significantly higher in the first two minutes after birth, and then from minute 10 to 60 (p < 0.003). There were no differences by gender in SpO2 and HR.
CONCLUSION
In term newborns, the SpO2 increases progressively, being higher in the first 10 minutes in those born vaginally. In newborns delivered vaginally, a higher HR was also observed in the first and last minutes evaluated.
Topics: Cesarean Section; Delivery, Obstetric; Female; Heart Rate; Humans; Infant, Newborn; Male; Oximetry; Oxygen; Prospective Studies; Time Factors
PubMed: 31859711
DOI: 10.32641/rchped.v90i4.964 -
American Journal of Perinatology Aug 2020This study was aimed to systematically review the use of filtering facepiece respirators, such asN95 masks, during pregnancy.
OBJECTIVE
This study was aimed to systematically review the use of filtering facepiece respirators, such asN95 masks, during pregnancy.
STUDY DESIGN
A comprehensive search for primary literature using Medline, Embase, Scopus, Web of Science, and ClinicalTrials.gov was conducted from inception until April 2020 to find articles reporting outcomes of pregnant women using filtering facepiece respirator (FFR). Studies were selected if they included the use of FFR in pregnant women and reported an outcome of interest including physiologic changes (heart rate, respiratory rate, pulse oximetry, and fetal heart rate tracing) or subjective measures (thermal or exertional discomfort or fit). The Newcastle-Ottawa Quality Assessment scale was used to assess the risk of bias. The main outcome was to describe the physiologic changes in pregnant women compared with nonpregnant women. Due to the small number of studies and heterogeneity of reported outcomes a meta-analysis was not conducted. Results of the studies were synthesized into a summary of evidence table.
RESULTS
We identified four studies, three cohort studies and one crossover study, comprising 42 women using FFR during pregnancy. Risk of bias was judged to be low. Studies were consistent in showing no significant increase in maternal heart rate, respiratory rate, oxygen saturation, and fetal heart rate between pregnant and nonpregnant women using N95 FFRs for short durations. Repeat fit testing was not supported for women gaining the recommended amount of weight during pregnancy. No evidence was found to reach conclusions about prolonged N95 FFR use in pregnancy.
CONCLUSION
Limited duration N95 FFR use during pregnancy is unlikely to impart risk to the pregnant women or her fetus.
KEY POINTS
· Limited N95 use unlikely to impart risk to pregnant woman/fetus.. · Prolonged N95 use in pregnancy is unstudied.. · Repeat fit testing in pregnancy likely unnecessary..
Topics: Carbon Dioxide; Equipment Design; Female; Fetal Heart; Heart Rate; Humans; N95 Respirators; Oxygen; Pregnancy; Respiratory Rate; Risk Assessment
PubMed: 32438427
DOI: 10.1055/s-0040-1712475