Differences in V˙O2max Measurements Between Breath-by-Breath and Mixing-Chamber Mode in the COSMED K5

2020 ◽  
pp. 1-6
Author(s):  
Kay Winkert ◽  
Johannes Kirsten ◽  
Rupert Kamnig ◽  
Jürgen M. Steinacker ◽  
Gunnar Treff
Keyword(s):  
Respiratory Exchange Ratio ◽  
Minute Ventilation ◽  
Maximal Oxygen Consumption ◽  
Cycle Ergometer ◽  
The Other ◽  
Endurance Athletes ◽  
Effect Sizes ◽  
Portable Devices ◽  
Incremental Test ◽  
Mixing Chamber

Purpose: Automated metabolic analyzers are frequently utilized to measure maximal oxygen consumption (). However, in portable devices, the results may be influenced by the analyzer’s technological approach, being either breath-by-breath (BBB) or dynamic micro mixing chamber mode (DMC). The portable metabolic analyzer K5 (COSMED, Rome, Italy) provides both technologies within one device, and the authors aimed to evaluate differences in between modes in endurance athletes. Methods: Sixteen trained male participants performed an incremental test to voluntary exhaustion on a cycle ergometer, while ventilation and gas exchange were measured by 2 structurally identical COSMED K5 metabolic analyzers synchronously, one operating in BBB and the other in DMC mode. Except for the flow signal, which was measured by 1 sensor and transmitted to both devices, the devices operated independently. was defined as the highest 30-second average. Results: and were significantly lower in BBB compared with DMC mode (−4.44% and −2.71%), with effect sizes being large to moderate (ES, Cohen d = 0.82 and 1.87). Small differences were obtained for respiratory frequency (0.94%, ES = 0.36), minute ventilation (0.29%, ES = 0.20), and respiratory exchange ratio (1.74%, ES = 0.57). Conclusion: was substantially lower in BBB than in DMC mode. Considering previous studies that also indicated lower values in BBB at high intensities and a superior validity of the K5 in DMC mode, the authors conclude that the DMC mode should be selected to measure in athletes.

Responses to Different Intermittent Runs at Velocity Associated With

2003 ◽  
Vol 28 (3) ◽  
pp. 410-423 ◽  
Author(s):  
Gregoire P. Millet ◽  
Robin Candau ◽  
Philippe Fattori ◽  
Frank Bignet ◽  
Alain Varray
Keyword(s):  
Maximal Oxygen Consumption ◽  
Interval Training ◽  
The Other ◽  
Time To Exhaustion ◽  
Interval Duration ◽  
Peak Heart Rate ◽  
Incremental Test ◽  
Performance Time ◽  
The Difference

The purposes of this study were (1) to determine the time sustained above 90% of [Formula: see text] in different intermittent running sessions having the same overall time run at the velocity ([Formula: see text]) associated with [Formula: see text] and (2) to test whether the use of a fixed-fraction (50%) of the time to exhaustion at [Formula: see text] (Tlim) leads to longer time spent at a high percentage of [Formula: see text]. Subjects were 8 triathletes who, after determination of their track [Formula: see text] and Tlim, performed three intermittent running sessions alternating the velocity between 100% and 50% of [Formula: see text], termed 30s ∼ 30s, 60s ∼ 30s, and 1/2Tlim ∼ 1/2Tlim, where the overall time at [Formula: see text] was similar (= 3 × Tlim). [Formula: see text] achieved in the incremental test was 71.1 ± 3.9 mlùmin−1•kg−1 and Tlim was 236 ± 49 s. [Formula: see text] and peak heart rate were lower in 30s ∼ 30s than in the other intermittent runs. The time spent above 90% of [Formula: see text] was significantly (p < 0.001) longer either in 60s ∼ 30s (531 ± 187 s) or in 1/2Tlim ∼ 1/2Tlim (487 ± 176 s) than in 30s ∼ 30s (149 ± 33 s). Tlim was negatively correlated with the time (in % of Tlim) spent above 90% of [Formula: see text] in 30s ∼ 30s (r = -0.75, p < 0.05). Tlim was also correlated with the difference of time spent over 90% of [Formula: see text] between 60s ∼ 30s and 30s ∼ 30s (r = 0.77, p < 0.05), or between 1/2Tlim ∼ 1/2Tlim and 30s ∼ 30s (r = 0.97, p < 0.001). The results confirm that [Formula: see text] and Tlim are useful for setting interval-training sessions. However, the use of an individualized fixed-fraction of Tlim did not lead to longer time spent at a high percentage of [Formula: see text] compared to when using a fixed work-interval duration. Key words: interval-training, maximal oxygen consumption, performance, time to exhaustion

Continuous measurement of breathlessness during exercise: validity, reliability, and responsiveness

2001 ◽  
Vol 90 (6) ◽  
pp. 2188-2196 ◽  
Author(s):  
Donald A. Mahler ◽  
Roberto Mejia-Alfaro ◽  
Joseph Ward ◽  
John C. Baird
Keyword(s):  
Oxygen Consumption ◽  
Rating Scale ◽  
Minute Ventilation ◽  
Regression Line ◽  
Maximal Oxygen Consumption ◽  
Young Female ◽  
Continuous Method ◽  
Incremental Test ◽  
Discrete Method ◽  
Physiological Variables

A continuous method for recording changes in breathlessness (dyspnea) during exercise is introduced and compared with the traditional discrete method. In study 1, a category-rating scale was presented on a computer screen, and 14 healthy, young female subjects exercised on a cycle ergometer until exhaustion. Two approaches were used to obtain ratings of breathlessness: a discrete method, in which subjects gave single judgments every minute, and a continuous method, in which subjects throughout exercise moved the mouse so that a bar on the screen extended to the desired location along the scale. Psychophysical results relating measures of breathlessness and the variables of work, oxygen consumption, and minute ventilation were statistically indistinguishable with the two methods, and both methods were highly reliable across test sessions. In study 2, both measurement methods were employed, and the subjects were 14 healthy, young males. In each of two sessions (discrete or continuous method), subjects first rated their breathlessness during an incremental test in which the workload was increased over time and levels of work, and minute ventilation were recorded. Subjects then exercised for 10 min at 60% of the maximal oxygen consumption achieved during the incremental test. At two points during steady-state exercise, a respiratory load was introduced that lasted for 1 min. It was possible to determine the responsiveness of subjects to onset and offset of the respiratory load for the continuous method but not for the discrete method. In study 3, patients with chronic obstuctive pulmonary disease employed both methods, and it was found that the continuous method was better at determining whether subjects showed a significant positive slope of the regression line between breathlessness ratings and physiological variables.

Human ventilatory responsiveness to hypoxia is unrelated to maximal aerobic capacity

2006 ◽  
Vol 100 (4) ◽  
pp. 1204-1209 ◽  
Author(s):  
A. William Sheel ◽  
Michael S. Koehle ◽  
Jordan A. Guenette ◽  
Glen E. Foster ◽  
Benjamin C. Sporer ◽  
...  
Keyword(s):  
Aerobic Capacity ◽  
Minute Ventilation ◽  
Maximal Oxygen Consumption ◽  
Endurance Athletes ◽  
Physical Conditioning ◽  
Maximal Aerobic Capacity ◽  
Ventilatory Control ◽  
Wide Range ◽  
Per Se ◽  
The Relationship

Ventilatory responsiveness to hypoxia (HVR) has been reported to be different between highly trained endurance athletes and healthy sedentary controls. However, a linkage between aerobic capacity and HVR has not been a universal finding. The purpose of this study was to examine the relationship between HVR and maximal oxygen consumption (V̇o2 max) in healthy men with a wide range of aerobic capacities. Subjects performed a HVR test followed by an incremental cycle test to exhaustion. Participants were classified according to their maximal aerobic capacity. Those with a V̇o2 max of ≥60 ml·kg−1·min−1 were considered highly trained ( n = 13); those with a V̇o2 max of 50–60 ml·kg−1·min−1 were considered moderately-trained ( n = 18); and those with a V̇o2 max of <50 ml·kg−1·min−1 were considered untrained ( n = 24). No statistical differences were detected between the three groups for HVR ( P > 0.05), and the HVR values were variable within each group (range: untrained = 0.28–1.61, moderately trained = 0.23–2.39, and highly trained = 0.08–1.73 l·min·%arterial O2 saturation−1). The relationship between HVR and V̇o2 max was not statistically significant ( r = −0.1723; P > 0.05). HVR was also unrelated to maximal minute ventilation and ventilatory equivalents for O2 and CO2. We found that a spectrum of hypoxic ventilatory control is present in well-trained endurance athletes and moderately and untrained men. We interpret these observations to mean that other factors are more important in determining hypoxic ventilatory control than physical conditioning per se.

Acid-base, metabolic, and ventilatory responses to repeated bouts of exercise

1982 ◽  
Vol 53 (2) ◽  
pp. 436-439 ◽  
Author(s):  
M. J. Buono ◽  
F. B. Roby
Keyword(s):  
Respiratory Exchange Ratio ◽  
Minute Ventilation ◽  
Co2 Flux ◽  
Cycle Ergometer ◽  
Mirror Image ◽  
Co2 Production ◽  
Acid Base ◽  
Subsequent Performance ◽  
Ventilatory Responses ◽  
Male Subjects

Acid-base, metabolic, and ventilatory responses to repeated bouts of exercise were examined. Ten male subjects performed two (T1, T2) 5-min work tests, on a cycle ergometer, separated by a 25-min rest. The results indicate the following. 1) T2 appears to have a larger aerobic energy component than T1, due to the fact that cumulative O2 uptake (Vo2) was significantly larger for T2 and that the immediate postexercise lactic acid (HLa) and delta HLa values were both significantly smaller for T2.2) CO2 production (Vco2) and the respiratory exchange ratio were both significantly lower for T2. This is probably due to greater fat metabolism and less nonmetabolic CO2 being produced from bicarbonate (HCO-3) buffering of HLa during T2.3) Even though Vco2 was significantly lower during T2, minute ventilation (VE) was not significantly different between T1 and T2. This suggests that the ventilatory response during exercise cannot be solely mediated via CO2 flux to the lungs. 4) HLa removal and (HCO-3) regeneration appear to be sequentially linked together as indicated by the almost identical mirror image and significant -0.93 correlation. In conclusion, it appears that a bout of high-intensity exercise (T1) can alter the acid-base and metabolic responses seen during subsequent performance (T2).

A Comparison of Physiological Demand between Self-Propelled and Motorized Treadmill Exercise

2018 ◽  
Vol 7 (4) ◽  
pp. 13-21
Author(s):  
Todd Backes ◽  
Charlene Takacs
Keyword(s):  
Respiratory Exchange Ratio ◽  
Treadmill Exercise ◽  
Cardiopulmonary Exercise Testing ◽  
Mean Value ◽  
The Self ◽  
Mixing Chamber ◽  
Wide Range ◽  
The Subject ◽  
The Mean ◽  
Computer Controlled

There are a wide range of options for individuals to choose from in order to engage in aerobic exercise; from outdoor running to computer controlled and self-propelled treadmills. Recently, self-propelled treadmills have increased in popularity and provide an alternative to a motorized treadmill. Twenty subjects (10 men, 10 women) ranging in age from 19-23 with a mean of 20.4 ± 0.8 SD were participants in this study. The subjects visited the laboratory on three occasions. The purpose of the first visit was to familiarize the subject with the self-propelled treadmill (Woodway Curve 3.0). The second visit, subjects were instructed to run on the self-propelled treadmill for 3km at a self-determined pace. Speed data were collected directly from the self-propelled treadmill. The third visit used speed data collected during the self-propelled treadmill run to create an identically paced 3km run for the subjects to perform on a motorized treadmill (COSMED T150). During both the second and third visit, oxygen consumption (VO2) and respiratory exchange ratio (R) data were collected with COSMED’s Quark cardiopulmonary exercise testing (CPET) metabolic mixing chamber system. The VO2 mean value for the self-propelled treadmill (44.90 ± 1.65 SE ml/kg/min) was significantly greater than the motorized treadmill (34.38 ± 1.39 SE ml/kg/min). The mean R value for the self-propelled treadmill (0.91 ± 0.01 SE) was significantly greater than the motorized treadmill (0.86 ± 0.01 SE). Our study demonstrated that a 3km run on a self-propelled treadmill does elicit a greater physiological response than a 3km run at on a standard motorized treadmill. Self-propelled treadmills provide a mode of exercise that offers increased training loads and should be considered as an alternative to motorized treadmills.

Cardiorespiratory responses to exercise distributed between the upper and lower body

1983 ◽  
Vol 54 (5) ◽  
pp. 1403-1407 ◽  
Author(s):  
M. M. Toner ◽  
M. N. Sawka ◽  
L. Levine ◽  
K. B. Pandolf
Keyword(s):  
Respiratory Exchange Ratio ◽  
Venous Return ◽  
Minute Ventilation ◽  
Peripheral Resistance ◽  
Upper Body ◽  
Lower Body ◽  
Upper Body Exercise ◽  
Cardiorespiratory Responses ◽  
Muscle Groups ◽  
Constant Power Output

The present study examined the influence that distributing exercise between upper (arm crank exercise) and lower (cycle exercise) body muscle groups had on cardiorespiratory responses to constant power output (PO) exercise. Six male volunteers completed five submaximal exercise bouts of 7-min duration at both 76 and 109 W. The arm PO/total PO (% arm) for these bouts was approximately 0, 20, 40, 60, and 100%. At 76 W, O2 uptake (VO2) did not change (P greater than 0.05) from 0 to approximately 20% arm (approximately 1.30 1 x min-1) but increased with increasing percent arm values up to 100% (1.58 1 x min-1). At 109 W, VO2 increased throughout the range of 0 (1.70 1 x min-1) to 100% arm (2.33 1 x min-1). In general, minute ventilation (VE) and respiratory exchange ratio (R) increased with increased percent arm values at 76 and 109 W. The heart rate (HR) responses remained unchanged from 0 to 60% arm at both 76 and 109 W; however, between 60 and 100% arm, a 26-beats x min-1 increase was observed at 76 W (143 beats x min-1 at 100% arm) and a 45-beats x min-1 increase at 109 W (174 beats x min-1 at 100% arm). These data suggested that during upper body exercise, the increased VO2 associated with increased percent arm values was not accompanied by an elevated HR response when at least 40% of the PO was performed by the lower body. This might be attributed to a facilitated venous return and/or a decreased total peripheral resistance when the lower body was involved in the exercise.

Responses to Intermittent Swimming Sets at Velocity Associated With max

2005 ◽  
Vol 30 (5) ◽  
pp. 543-553 ◽  
Author(s):  
Sebastien Libicz ◽  
Belle Roels ◽  
Gregoire P. Millet
Keyword(s):  
Oxygen Consumption ◽  
Maximal Oxygen Consumption ◽  
Interval Training ◽  
Swimming Velocity ◽  
Time Duration ◽  
Incremental Test ◽  
Large Variability ◽  
Equal Time ◽  
Physiological Adaptations ◽  
The Times

While the physiological adaptations following endurance training are relatively well understood, in swimming there is a dearth of knowledge regarding the metabolic responses to interval training (IT). The hypothesis tested predicted that two different endurance swimming IT sets would induce differences in the total time the subjects swam at a high percentage of maximal oxygen consumption [Formula: see text]. Ten trained triathletes underwent an incremental test to exhaustion in swimming so that the swimming velocity associated with [Formula: see text][Formula: see text] could be determined. This was followed by a maximal 400-m test and two intermittent sets at [Formula: see text] (a) 16 × 50 m with 15-s rest (IT50); (b) 8 × 100 m with 30-s rest (IT100). The times sustained above 95% [Formula: see text] (68.50 ± 62.69 vs. 145.01 ± 165.91 sec) and 95% HRmax (146.67 ± 131.99 vs. 169.78 ± 203.45 sec, p = 0.54) did not differ between IT50 and IT100 (values are mean ± SD). In conclusion, swimming IT sets of equal time duration at [Formula: see text] but of differing work-interval durations led to slightly different [Formula: see text] and HR responses. The time spent above 95% of [Formula: see text]max was twice as long in IT100 as in IT50, and a large variability between mean [Formula: see text] and HR values was also observed. Key words: interval training, maximal oxygen consumption, triathletes

Effect of sleep on nocturnal bronchoconstriction and ventilatory patterns in asthmatics

1989 ◽  
Vol 67 (1) ◽  
pp. 243-249 ◽  
Author(s):  
R. D. Ballard ◽  
M. C. Saathoff ◽  
D. K. Patel ◽  
P. L. Kelly ◽  
R. J. Martin
Keyword(s):  
Airway Resistance ◽  
Minute Ventilation ◽  
The Other ◽  
Lower Airway ◽  
Sleep Laboratory ◽  
Sleep State ◽  
Asthmatic Patients ◽  
Ventilatory Responses ◽  
Rate Of Increase ◽  
Normal Controls

To assess the effect of sleep on airflow resistance and patterns of ventilation in asthmatic patients with nocturnal worsening, 10 adult subjects (6 asthmatic patients with nocturnal worsening, 4 normal controls) were monitored overnight in the sleep laboratory on two separate occasions. During 1 night, subjects were allowed to sleep normally, whereas during the other night all sleep was prevented. The six asthmatic patients demonstrated progressive increases in lower airway resistance (Rla) on both nights, but the rate of increase was twofold greater (P less than 0.0001) during the sleep night compared with the sleep prevention night. However, overnight decrements in forced expired volume in 1 s (FEV1) were similar over the 2 nights. The asthmatic patients maintained their minute ventilation as Rla increased during sleep, demonstrating a stable tidal volume with a mild increase in respiratory frequency. We conclude that in asthmatic patients with nocturnal worsening 1) Rla increases and FEV1 falls overnight regardless of sleep state, 2) sleep enhances the observed overnight increases in Rla, and 3) sleep does not abolish compensatory ventilatory responses to spontaneously occurring bronchoconstriction.

Living high-training low increases hypoxic ventilatory response of well-trained endurance athletes

2002 ◽  
Vol 93 (4) ◽  
pp. 1498-1505 ◽  
Author(s):  
Nathan E. Townsend ◽  
Christopher J. Gore ◽  
Allan G. Hahn ◽  
Michael J. McKenna ◽  
Robert J. Aughey ◽  
...  
Keyword(s):  
Ventilatory Response ◽  
Minute Ventilation ◽  
Respiratory Control ◽  
Endurance Athletes ◽  
Hypoxic Exposure ◽  
Dependent Manner ◽  
Hypoxic Ventilatory Response ◽  
Ambient Conditions ◽  
Altitude Exposure ◽  
End Tidal

This study determined whether “living high-training low” (LHTL)-simulated altitude exposure increased the hypoxic ventilatory response (HVR) in well-trained endurance athletes. Thirty-three cyclists/triathletes were divided into three groups: 20 consecutive nights of hypoxic exposure (LHTLc, n = 12), 20 nights of intermittent hypoxic exposure (four 5-night blocks of hypoxia, each interspersed with 2 nights of normoxia, LHTLi, n = 10), or control (Con, n = 11). LHTLc and LHTLi slept 8–10 h/day overnight in normobaric hypoxia (∼2,650 m); Con slept under ambient conditions (600 m). Resting, isocapnic HVR (ΔV˙e/ΔSpO2 , whereV˙e is minute ventilation and SpO2 is blood O2 saturation) was measured in normoxia before hypoxia (Pre), after 1, 3, 10, and 15 nights of exposure (N1, N3, N10, and N15, respectively), and 2 nights after the exposure night 20 (Post). Before each HVR test, end-tidal Pco 2(Pet CO2 ) and V˙e were measured during room air breathing at rest. HVR (l · min−1 · %−1) was higher ( P < 0.05) in LHTLc than in Con at N1 (0.56 ± 0.32 vs. 0.28 ± 0.16), N3 (0.69 ± 0.30 vs. 0.36 ± 0.24), N10 (0.79 ± 0.36 vs. 0.34 ± 0.14), N15 (1.00 ± 0.38 vs. 0.36 ± 0.23), and Post (0.79 ± 0.37 vs. 0.36 ± 0.26). HVR at N15 was higher ( P < 0.05) in LHTLi (0.67 ± 0.33) than in Con and in LHTLc than in LHTLi. Pet CO2 was depressed in LHTLc and LHTLi compared with Con at all points after hypoxia ( P < 0.05). No significant differences were observed for V˙e at any point. We conclude that LHTL increases HVR in endurance athletes in a time-dependent manner and decreases Pet CO2 in normoxia, without change inV˙e. Thus endurance athletes sleeping in mild hypoxia may experience changes to the respiratory control system.

scholarly journals Being Easy to Communicate Might Make Verdicts Based on Confessions More Legitimate

2021 ◽  
Vol 21 (3-4) ◽  
pp. 203-225
Author(s):  
Hugo Mercier ◽  
Anne-Sophie Hacquin ◽  
Nicolas Claidière
Keyword(s):  
The Other ◽  
Circumstantial Evidence ◽  
Common Variant ◽  
Effect Sizes ◽  
Medium Effect ◽  
Criminal Conviction ◽  
Transmission Process ◽  
English Speaking ◽  
Judicial Systems

Abstract In many judicial systems, confessions are a requirement for criminal conviction. Even if confessions are intrinsically convincing, this might not entirely explain why they play such a paramount role. In addition, it has been suggested that confessions owe their importance to their legitimizing role, explaining why they could be required even when other evidence has convinced a judge. But why would confessions be particularly suited to justify verdicts? One possibility is that they can be more easily transmitted from one individual to the next, and thus spread in the population without losing their convincingness. 360 English-speaking participants were asked to evaluate the convincingness of one of three justifications for a verdict, grounded either in a confession, eyewitnesses, or circumstantial evidence, and to pass on that justification to another participant, who performed the same task. Then, 240 English-speaking participants evaluated the convincingness of some of the justifications produced by the first group of participants. Compared to the other justifications, justifications based on confessions lost less of their convincingness in the transmission process (small to medium effect sizes). Modeling pointed to the most common forms the justifications would take as they are transmitted, and results showed that the most common variant of the justification based on a confession was more convincing (small to medium effect sizes).

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