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Sensors (Basel, Switzerland) Aug 2023The purpose of this study was two-fold: (1) to determine the sensitivity of the sEMG shorts-derived training load (sEMG-TL) during different running speeds; and (2) to...
The purpose of this study was two-fold: (1) to determine the sensitivity of the sEMG shorts-derived training load (sEMG-TL) during different running speeds; and (2) to investigate the relationship between the oxygen consumption, heart rate (HR), rating of perceived exertion (RPE), accelerometry-based PlayerLoad (PL), and sEMG-TL during a running maximum oxygen uptake (V˙O) test. The study investigated ten healthy participants. On day one, participants performed a three-speed treadmill test at 8, 10, and 12 km·h for 2 min at each speed. On day two, participants performed a V˙O test. Analysis of variance found significant differences in sEMG-TL at all three speeds ( < 0.05). A significantly weak positive relationship between sEMG-TL and %V˙O ( = 0.31, < 0.05) was established, while significantly strong relationships for 8 out of 10 participants at the individual level ( = 0.72-0.97, < 0.05) were found. Meanwhile, the accelerometry PL was not significantly related to %V˙O ( > 0.05) and only demonstrated significant correlations in 3 out of 10 participants at the individual level. Therefore, the sEMG shorts-derived training load was sensitive in detecting a work rate difference of at least 2 km·h. sEMG-TL may be an acceptable metric for the measurement of internal loads and could potentially be used as a surrogate for oxygen consumption.
Topics: Humans; Exercise Test; Physical Exertion; Oxygen Consumption; Oxygen; Running; Heart Rate
PubMed: 37571780
DOI: 10.3390/s23156998 -
International Journal of Environmental... Dec 2022The effects of aquatic high-intensity interval training (AHIIT) on cardiometabolic and perceptive responses when compared to similar land-based exercise (LHIIT) remain...
The effects of aquatic high-intensity interval training (AHIIT) on cardiometabolic and perceptive responses when compared to similar land-based exercise (LHIIT) remain unknown. Here, we aimed to (1) establish a matched intensity between mediums and (2) compare the acute cardiometabolic and perceptive responses to the two interventions in healthy young women. Twenty healthy young women performed a stationary running exercise at a matched exercise intensity. The incremental stages, in terms of percentage of heart rate (HR), maximal oxygen uptake (%VOmax), percentage of oxygen uptake reserve (%VOR), percentage of heart rate reserve (%HRR), and rate of perceived exertion (RPE), were examined and acute cardiometabolic and perceptive responses were evaluated. The results showed that HR was significantly reduced (AHIIT: W 150 ± 19, R 140 ± 18, LHIIT: W 167 ± 16, R 158 ± 16 < 0.01) and oxygen pulse (AHIIT: W 12 ± 2, R 10 ± 2, LHIIT: W 11 ± 2, R 9 ± 2 < 0.05) was significantly increased with AHIIT compared to LHIIT. No significant group differences were observed for the perceptive responses. The comparable results demonstrated by the aquatic and land incremental tests allow precise AHIIT and LHIIT prescriptions. AHIIT had distinct differences in HR and oxygen pulse, despite having no distinct difference from LHIIT for some cardiometabolic and affective responses.
Topics: Humans; Female; High-Intensity Interval Training; Oxygen Consumption; Exercise Test; Heart Rate; Cardiovascular Diseases; Oxygen; Physical Exertion
PubMed: 36554639
DOI: 10.3390/ijerph192416761 -
Archives of Disease in Childhood. Fetal... Nov 2003Pulse oximetry is widely used in neonates. However, its reliability is often affected by motion artefact. Clinicians confronted with questionable oxygen saturation... (Comparative Study)
Comparative Study
BACKGROUND
Pulse oximetry is widely used in neonates. However, its reliability is often affected by motion artefact. Clinicians confronted with questionable oxygen saturation (SpO(2)) values often estimate the reliability by correlating heart rate (HR) obtained with the oximeter with that obtained by electrocardiogram.
OBJECTIVE
To compare the effects of motion on SpO(2) and HR measurements made with Masimo signal extraction technology and those made with a Nellcor N-200.
DESIGN
Continuous pulse oximetry and HR monitoring were performed in 15 healthy, term infants (mean (SD) birth weight 3408 (458) g) undergoing circumcision, using Masimo and Nellcor pulse oximeters and a standard HR monitor (Hewlett-Packard). Simultaneous minute by minute behavioural activity codes were also assigned. Baseline data were collected for 10 minutes when the infant was quietly asleep and then continued during and after circumcision for a total duration of one hour. The oximeter HR and SpO(2) values were compared and related to HR values obtained by ECG during all three periods. The effect of behavioural activity on SpO(2) and HR was also evaluated.
RESULTS
When compared with results obtained with the Nellcor, the mean SpO(2) and HR were higher and the incidence of artefact lower with the Masimo during all three periods. Masimo HR more accurately predicted HR obtained with a standard monitor, with lower residual error. SpO(2) and HR values obtained with the Nellcor were lower and more variable during all behavioural states, especially crying, when excessive motion artefact was most likely.
CONCLUSIONS
The data suggest that Masimo signal extraction technology may offer improvement in pulse oximetry performance, particularly in clinical situations in which extreme motion artefacts are likely.
Topics: Artifacts; Electrocardiography; Heart Rate; Humans; Infant, Newborn; Male; Movement; Oximetry; Oxygen; Sleep
PubMed: 14602699
DOI: 10.1136/fn.88.6.f505 -
Respiratory Physiology & Neurobiology Sep 2023We aimed to investigate respiratory rate variability (RRV) and tidal volume (V) variability during exposure to normobaric hypoxia (i.e., reduction in the fraction of...
PURPOSE
We aimed to investigate respiratory rate variability (RRV) and tidal volume (V) variability during exposure to normobaric hypoxia (i.e., reduction in the fraction of inspired oxygen - FiO), and the association of the changes in RRV and V variability with the changes in pulse oxygen saturation (SpO).
METHODS
Thirty healthy human participants (15 females) were exposed to: (1) 15-min normoxia, (2) 10-min hypoxia simulating 2200 m, (3) 10-min hypoxia simulating 4000 m, (4) 10-min hypoxia simulating 5000 m, (5) 15-min recovery in normoxia. Linear regression modelling was applied with SpO (dependent variable) and the changes in RRV and V variability (independent variables), controlling for FiO, age, sex, changes in heart rate (HR), changes in HR variability (HRV), and changes in minute ventilation (V).
RESULTS
When modelling breathing parameter variability as root-mean-square standard deviation (RMSSD), a significant independent association of the changes in RRV with the changes in SpO was found (B = -4.3e-04, 95% CI = -8.3e-04/-2.1e-05, p = 0.04). The changes in V variability showed no significant association with the changes in SpO (B = -1.6, 95% CI = -5.5/2.4, p = 0.42). When modelling parameters variability as SD, a significant independent association of the changes in RRV with the changes in SpO was found (B = -8.2e-04, 95% CI = -1.5e-03/-9.4e-05, p = 0.03). The changes in V variability showed no significant association with the changes in SpO (B=1.4, 95% CI = -5.8/8.6, p = 0.69).
CONCLUSION
Higher RRV is independently associated with lower SpO during acute hypoxic exposure, while V variability parameters are not. Therefore, RRV may be a potentially interesting parameter to characterize individual responses to acute hypoxia.
Topics: Female; Humans; Pilot Projects; Hypoxia; Respiration; Respiratory Rate; Heart Rate; Oxygen
PubMed: 37355056
DOI: 10.1016/j.resp.2023.104096 -
Diving and Hyperbaric Medicine Mar 2023Recreational freedivers typically perform repeated dives to moderate depths with short recovery intervals. According to freediving standards, these recovery intervals...
INTRODUCTION
Recreational freedivers typically perform repeated dives to moderate depths with short recovery intervals. According to freediving standards, these recovery intervals should be twice the dive duration; however, this has yet to be supported by scientific evidence.
METHODS
Six recreational freedivers performed three freedives to 11 metres of freshwater (mfw), separated by 2 min 30 s recovery intervals, while an underwater pulse oximeter measured peripheral oxygen saturation (SpO) and heart rate (HR).
RESULTS
Median dive durations were 54.0 s, 103.0 s and 75.5 s (all dives median 81.5 s). Median baseline HR was 76.0 beats per minute (bpm), which decreased during dives to 48.0 bpm in dive one, 40.5 bpm in dive two and 48.5 bpm in dive three (all P < 0.05 from baseline). Median pre-dive baseline SpO was 99.5%. SpO remained similar to baseline for the first half of the dives, after which the rate of desaturation increased during the second half of the dives with each subsequent dive. Lowest median SpO after dive one was 97.0%, after dive two 83.5% (P < 0.05 from baseline) and after dive three 82.5% (P < 0.01 from baseline). SpO had returned to baseline within 20 s after all dives.
CONCLUSIONS
We speculate that the enhanced rate of arterial oxygen desaturation across the serial dives may be attributed to a remaining 'oxygen debt', leading to progressively increased oxygen extraction by desaturated muscles. Despite being twice the dive duration, the recovery period may be too short to allow full recovery and to sustain prolonged serial diving, thus does not guarantee safe diving.
Topics: Humans; Oximetry; Oxygen; Diving; Heart Rate; Oxygen Consumption
PubMed: 36966518
DOI: 10.28920/dhm53.1.16-23 -
Medical Science Monitor : International... Mar 2021BACKGROUND Hypoxic hypoperfusion injury in the brain is a cause of potential injury and even death in the growth period of newborns. Therefore, monitoring regional... (Observational Study)
Observational Study
BACKGROUND Hypoxic hypoperfusion injury in the brain is a cause of potential injury and even death in the growth period of newborns. Therefore, monitoring regional cerebral oxygen saturation (CrSO₂) during this period is particularly important. This observational clinical study from a single center aimed to investigate the factors associated with CrSO₂ in full-term newborn infants during birth transition. MATERIAL AND METHODS We enrolled 84 full-term newborn infants delivered by cesarean section. We started the stopwatch with the obstetrician clamping the newborns' umbilical cords and recorded the values of newborns' CrSO₂, pulse oxygen saturation (SpO₂), pulse rate (PR), end-tidal carbon dioxide (EtCO₂), and respiratory rate (RR) at 2 min, 5 min, and 10 min. We weighed the newborns before they left the operating room and used statistical methods to compare the correlation between each observation factor. RESULTS Pearson correlation coefficients between CrSO₂ and SpO₂ measured at 2 min, 5 min, and 10 min were 0.491, 0.599, and 0.587, respectively (P<0.01). Pearson correlation coefficients between CrSO₂ and EtCO₂ measured at 2 min, 5 min, and 10 min were -0.304, -0.443, and -0.243, respectively (P<0.05). Regardless of a newborn's weight, PR, or RR, the correlation between any of those factors and the value of CrSO₂ measured at the corresponding time point had no significance (P>0.05). CONCLUSIONS This study showed a correlation between CrSO₂ and SpO₂ and CrSO₂ and EtCO₂ during birth transition of full-term infants delivered by elective cesarean section, but CrSO₂ had no significant correlation with neonatal weight, PR, or RR.
Topics: Birth Weight; Brain; Carbon Dioxide; Cerebrovascular Circulation; Cesarean Section; Delivery, Obstetric; Female; Heart Rate; Humans; Infant, Newborn; Male; Oximetry; Oxygen; Oxygen Consumption; Parturition; Respiratory Rate
PubMed: 33746201
DOI: 10.12659/MSM.928750 -
American Journal of Veterinary Research May 2018OBJECTIVE To determine global and peripheral perfusion and oxygenation during anesthesia with equipotent doses of desflurane and propofol combined with a constant rate... (Comparative Study)
Comparative Study
Comparison of desflurane and propofol at equipotent doses in combination with a constant rate infusion of dexmedetomidine on global and peripheral perfusion and oxygenation in horses.
OBJECTIVE To determine global and peripheral perfusion and oxygenation during anesthesia with equipotent doses of desflurane and propofol combined with a constant rate infusion of dexmedetomidine in horses. ANIMALS 6 warmblood horses. PROCEDURES Horses were premedicated with dexmedetomidine (3.5 μg•kg, IV). Anesthesia was induced with propofol or ketamine and maintained with desflurane or propofol (complete crossover design) combined with a constant rate infusion of dexmedetomidine (7 μg•kg •h). Microperfusion and oxygenation of the rectal, oral, and esophageal mucosa were measured before and after sedation and during anesthesia at the minimal alveolar concentration and minimal infusion rate. Heart rate, mean arterial blood pressure, respiratory rate, cardiac output, and blood gas pressures were recorded during anesthesia. RESULTS Mean ± SD minimal alveolar concentration and minimal infusion rate were 2.6 ± 0.9% and 0.04 ± 0.01 mg•kg •min, respectively. Peripheral microperfusion and oxygenation decreased significantly after dexmedetomidine administration for both treatments. Oxygenation returned to baseline values, whereas tissue microperfusion remained low during anesthesia. There were no differences in peripheral tissue microperfusion and oxygenation between treatments. Cardiac index was significantly higher and systemic vascular resistance was significantly lower for desflurane treatment than for propofol treatment. For the propofol treatment, Pao was significantly higher and there was less dead space and venous admixture than for the desflurane treatment. CONCLUSIONS AND CLINICAL RELEVANCE Dexmedetomidine decreased blood flow and oxygen saturation in peripheral tissues. Peripheral tissues were well oxygenated during anesthesia with desflurane and propofol combined with dexmedetomidine, whereas blood flow was reduced.
Topics: Anesthesia; Animals; Blood Gas Analysis; Blood Pressure; Cardiac Output; Desflurane; Dexmedetomidine; Heart Rate; Hemodynamics; Horses; Isoflurane; Ketamine; Oxygen; Perfusion; Propofol; Respiratory Physiological Phenomena; Vascular Resistance
PubMed: 29688787
DOI: 10.2460/ajvr.79.5.487 -
International Journal of Environmental... Jul 2022Background: This study investigated the acute effects of two high-intensity interval training (HIIT) programs on physiological responses and internal workload. Methods:...
Background: This study investigated the acute effects of two high-intensity interval training (HIIT) programs on physiological responses and internal workload. Methods: Ten national-level adolescent male rowers (age: 15.7 ± 0.2 years; maximal oxygen uptake (VO2max): 60.11 ± 1.91 mL∙kg−1∙min−1) performed two HIIT testing sessions: short (S-HIIT) and long (L-HIIT). In S-HIIT, the rowers performed 25 reps of 30 s at 100% power at VO2max (Pmax) interspersed with 30 s at P@20% Pmax; whereas in L-HIIT, the rowers executed 4 × 4 min at P@90% Pmax interspersed with 3 min of active recovery (P@30% Pmax). Results: The acute physiological responses and internal workload were evaluated. The significance level was set at p < 0.05. Oxygen uptake (VO2) (p < 0.05), time spent per session at ~90% VO2max (p < 0.01), total VO2 consumed (p < 0.01), total distance (p < 0.001), the rating of perceived exertion, blood lactate concentration and heart rate (always p < 0.0001) were significantly higher in L-HIIT than in S-HIIT. However, peak power output was significantly lower in L-HIIT compared to S-HIIT (p < 0.0001). Conclusion: In adolescent rowers, both HIIT tests stimulated aerobic and anaerobic systems. The L-HIIT test was associated with acute cardiorespiratory and metabolic responses, as well as higher perceptions of effort than the S-HIIT test. In adolescent rowers, HIIT emerges as an asset and could be introduced into a traditional in-season, moderate-intensity and endurance-based rowing program once a week.
Topics: Adolescent; Heart Rate; High-Intensity Interval Training; Humans; Male; Oxygen; Oxygen Consumption; Water Sports
PubMed: 35805789
DOI: 10.3390/ijerph19138132 -
Military Medicine Feb 2024The subject of this study was the creation of a new type of laboratory walking stress test for the Special Forces of the Army of the Czech Republic. This study developed...
INTRODUCTION
The subject of this study was the creation of a new type of laboratory walking stress test for the Special Forces of the Army of the Czech Republic. This study developed a test model that has been validated in practice and that reflects the fact that the performance of endurance without and with a load varies considerably. Especially, if we focus on operators, as their activities are always performed with loads/full gear (equipment, weapons, equipment, etc.).
MATERIALS AND METHODS
24 men/operators from the Special Forces of the Army of the Czech Republic volunteered for this study. The maximal exercise test/spiroergometry was designed to include performance at a load of 55 kg/121 lb, a constant speed of 5.3 km/h, and an increase in incline angle of 1 degree after each elapsed minute. The test was performed on a treadmill under standard time, location, and temperature conditions. During the test, the following values were recorded: VO2 = oxygen consumption indicating the intensity of the exercise was monitored, VO2/kg = oxygen consumption converted to body weight, VO2/HR = pulse oxygen (the amount of oxygen converted in one heartbeat), HR = heart rate, VE = ventilation, volume of air exhaled in 1 min, breathe frequency (BF) = respiratory rate in 1 min.
RESULTS
Out of the total number of 24 respondents, the study found these mean values of variables. The variable mapping the oxygen consumption, which indicates the intensity of VO2 loading, was 3.8, with the lowest value being 3.2 and the highest being 4.5. After converting oxygen consumption to bodyweight, VO2/kg was 46, the lowest value of 38.8, and the highest 53.0 were measured for this variable. Pulse oxygen, i.e., the amount of oxygen calculated per heart contraction VO2/HR, was 20.5, the lowest value 16.0, and the highest 26.0. The average HR heart rate was 183.5, with the lowest value being recorded at 164 and the highest value is 205. Ventilation, i.e., the amount of exhaled air per minute in VE, was measured at 144.9, the lowest value was 114.7, and the highest was 176.6. The BF in 1 min was 58.5, the lowest value 35, and the highest 70. The mean time load was 10:20 min, the shortest test length was 7:25 min, and the longest was 13:23 min. These values correspond to the degree of inclination of the ascent, i.e., the mean value was 10 degrees, the smallest achieved slope was 7 degrees, and the largest 13 degrees.
CONCLUSION
The designed weighted walking test proved to be fully functional and effective in measurement. The further established protocol corresponds to the requirements of the current needs of the Special Forces of the Army of the Czech Republic. Last but not least, the walking stress test is applied for the external and internal selection and screening of operators. Data obtained from testing were used to develop deployment requirements for patrol/nuclear combat missions.
Topics: Male; Humans; Czech Republic; Oxygen Consumption; Exercise; Exercise Test; Heart Rate; Oxygen; Walking
PubMed: 37776528
DOI: 10.1093/milmed/usad387 -
Biomedical Engineering Online Oct 2014The switching exercise (e.g., Interval Training) has been a commonly used exercise protocol nowadays for the enhancement of exerciser's cardiovascular fitness. The...
BACKGROUND
The switching exercise (e.g., Interval Training) has been a commonly used exercise protocol nowadays for the enhancement of exerciser's cardiovascular fitness. The current difficulty for simulating human onset and offset exercise responses regarding the switching exercise is to ensure the continuity of the outputs during onset-offset switching, as well as to accommodate the exercise intensities at both onset and offset of exercise.
METHODS
Twenty-one untrained healthy subjects performed treadmill trials following both single switching exercise (e.g., single-cycle square wave protocol) and repetitive switching exercise (e.g., interval training protocol). During exercise, heart rate (HR) and oxygen uptake (VO2) were monitored and recorded by a portable gas analyzer (K4b 2, Cosmed). An equivalent single-supply switching resistance-capacitor (RC) circuit model was proposed to accommodate the observed variations of the onset and offset dynamics. The single-cycle square wave protocol was utilized to investigate the respective dynamics at onset and offset of exercise with the aerobic zone of approximate 70%-77% of HR max, and verify the adaption feature for the accommodation of different exercise strengths. The design of the interval training protocol was to verify the transient properties during onset-offset switching. A verification method including Root-mean-square-error (RMSE) and correlation coefficient, was introduced for comparisons between the measured data and model outputs.
RESULTS
The experimental results from single-cycle square wave exercises clearly confirm that the onset and offset characteristics for both HR and VO2 are distinctly different. Based on the experimental data for both single and repetitive square wave exercise protocols, the proposed model was then presented to simulate the onset and offset exercise responses, which were well correlated indicating good agreement with observations.
CONCLUSIONS
Compared with existing works, this model can accommodate the different exercise strengths at both onset and offset of exercise, while also depicting human onset and offset exercise responses, and guarantee the continuity of outputs during onset-offset switching. A unique adaption feature by allowing the time constant and steady state gain to re-shift back to their original states, more closely mimics the different exercise strengths during normal daily exercise activities.
Topics: Adult; Algorithms; Cardiovascular System; Exercise; Exercise Test; Gases; Healthy Volunteers; Heart Rate; Humans; Male; Middle Aged; Models, Theoretical; Oxygen
PubMed: 25326902
DOI: 10.1186/1475-925X-13-145