Physiological responses and air consumption during simulated firefighting tasks in a subway system

2010 ◽  
Vol 35 (5) ◽  
pp. 671-678 ◽  
Author(s):  
F. Michael Williams-Bell ◽  
Geoff Boisseau ◽  
John McGill ◽  
Andrew Kostiuk ◽  
Richard L. Hughson
Keyword(s):  
Carbon Dioxide ◽  
Oxygen Uptake ◽  
Energy Requirement ◽  
Average Energy ◽  
Peak Oxygen Uptake ◽  
Search And Rescue ◽  
Moderate Intensity ◽  
Physiological Strain ◽  
Carbon Dioxide Output ◽  
Subway System

Professional firefighters (33 men, 3 women), ranging in age from 30 to 53 years, participated in a simulation of a subway system search and rescue while breathing from their self-contained breathing apparatus (SCBA). We tested the hypothesis that during this task, established by expert firefighters to be of moderate intensity, the rate of air consumption would exceed the capacity of a nominal 30-min cylinder. Oxygen uptake, carbon dioxide output, and air consumption were measured with a portable breath-by-breath gas exchange analysis system, which was fully integrated with the expired port of the SCBA. The task involved descending a flight of stairs, walking, performing a search and rescue, retreat walking, then ascending a single flight of stairs to a safe exit. This scenario required between 9:56 and 13:24 min:s (mean, 12:10 ± 1:10 min:s) to complete, with an average oxygen uptake of 24.3 ± 4.5 mL·kg–1·min–1 (47 ± 10 % peak oxygen uptake) and heart rate of 76% ± 7% of maximum. The highest energy requirement was during the final single-flight stair climb (30.4 ± 5.4 mL·kg–1·min–1). The average respiratory exchange ratio (carbon dioxide output/oxygen uptake) throughout the scenario was 0.95 ± 0.08, indicating a high carbon dioxide output for a relatively moderate average energy requirement. Air consumption from the nominal “30-min” cylinder averaged 51% (range, 26%–68%); however, extrapolation of these rates of consumption suggested that the low-air alarm, signalling that only 25% of the air remains, would have occurred as early as 11 min for an individual with the highest rate of air consumption, and at 16 min for the group average. These data suggest that even the moderate physical demands of walking combined with search and rescue while wearing full protective gear and breathing through the SCBA impose considerable physiological strain on professional firefighters. As well, the rate of air consumption in these tasks classed as moderate, compared with high-rise firefighting, would have depleted the air supply well before the nominal time used to describe the cylinders.

Intratest reliability and test–retest reproducibility of the oxygen uptake efficiency slope in healthy participants

2009 ◽  
Vol 16 (4) ◽  
pp. 493-498 ◽  
Author(s):  
Christophe Van Laethem ◽  
Johan De Sutter ◽  
Wim Peersman ◽  
Patrick Calders
Keyword(s):  
Carbon Dioxide ◽  
Oxygen Uptake ◽  
Minute Ventilation ◽  
Exercise Duration ◽  
Peak Oxygen Uptake ◽  
Exercise Tests ◽  
Uptake Efficiency ◽  
Carbon Dioxide Output ◽  
Oxygen Uptake Efficiency Slope ◽  
Healthy Participants

Background The oxygen uptake efficiency slope (OUES) is a newer ventilatory exercise parameter, used in the evaluation of healthy participants and patients with cardiovascular disease. However, few data about the reliability and reproducibility of OUES are available. Our study assessed intratest reliability and test-retest reproducibility of OUES in healthy participants. Design and methods Eighteen participants (age 28 ± 6 years, BMI 22.1 ± 1.9 kg/m2, 10 men) performed two identical maximal exercise tests on a bicycle ergometer. To assess test-retest reproducibility, we performed Bland-Altman analysis and calculated the coefficient of repeatability of the main ventilatory variables. Results OUES remained stable during the second part of the exercise test. Mean values varied 2.4 ± 4.0% between OUES calculated at 70% (OUES70) and at 100% of exercise duration. Mean variation decreased to 1.4 ± 2.3% when OUES was calculated at 90% of exercise duration (OUES90). The Bland-Altman 95% limits of agreement for OUES90 were +3 and –6%, those for OUES70 were +11 and –8%. The coefficient of repeatability for OUES was 597 ml/min or 18.7% of the average value of repeated OUES measurements. These results were similar to those of peak oxygen uptake and minute ventilation/carbon dioxide output. However, the test-retest reproducibility for submaximal-derived values of OUES was lower, as we noted higher coefficients of repeatability for OUES90 and OUES70, increasing up to 27% of the average of repeated values. Conclusion OUES shows excellent intratest reliability and has a test-retest reproducibility that is similar to that of peak oxygen uptake and minute ventilation/carbon dioxide output slope. However, its reproducibility becomes higher when it is calculated from increasing levels of achieved exercise intensity.

The effects of 4 weeks of an arginine-based supplement on the gas exchange threshold and peak oxygen uptake

2010 ◽  
Vol 35 (3) ◽  
pp. 286-293 ◽  
Author(s):  
Clayton L. Camic ◽  
Terry J. Housh ◽  
Michelle Mielke ◽  
Jorge M. Zuniga ◽  
C. Russell Hendrix ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Gas Exchange ◽  
Oxygen Uptake ◽  
Power Output ◽  
Grape Seed ◽  
Peak Oxygen Uptake ◽  
Cycle Ergometer ◽  
Double Blind ◽  
Carbon Dioxide Output ◽  
Gas Exchange Threshold

The purpose of the present study was to examine the effects of the daily administration of an arginine-based supplement for 4 weeks on the gas exchange threshold (GET) and peak oxygen uptake. The study used a double-blind, placebo-controlled design. Forty-one college-aged males (mean age ± SD = 22.1 ± 2.4 years) were randomized into either the PLACEBO (n = 20) or ARGININE (n = 21) group. The placebo was microcrystalline cellulose. The ARGININE group ingested 3.0 g of arginine, 300 mg of grape seed extract, and 300 mg of polyethylene glycol. All subjects performed an incremental test to exhaustion on a cycle ergometer prior to supplementation (PRE) and after 4 weeks of supplementation (POST). The GET was determined by using the V-slope method of the carbon dioxide output vs. oxygen uptake relationship. The results indicated that there were significant mean increases (PRE to POST) in GET (4.1%), as well as in carbon dioxide output (4.3%) and power output (5.4%) at the GET for the ARGININE group, but no significant changes for the PLACEBO group (2.5%, 4.3%, and 3.9%, respectively). In addition, there were no significant changes in peak oxygen uptake for the ARGININE (–1.0%) or PLACEBO (–1.5%) groups. These findings supported the use of the arginine-based supplement for increasing GET and the associated power output, but not for increasing peak oxygen uptake during cycle ergometry.

Breathing in brief exercise

1960 ◽  
Vol 15 (4) ◽  
pp. 583-588 ◽  
Author(s):  
F. N. Craig ◽  
E. G. Cummings
Keyword(s):  
Carbon Dioxide ◽  
Oxygen Uptake ◽  
Respiratory Exchange Ratio ◽  
Metabolic Cost ◽  
Carbon Dioxide Tension ◽  
Minute Volume ◽  
Carbon Dioxide Output ◽  
Respiratory Minute Volume ◽  
Before And After

Two men ran for 20 or 60 seconds while inhaling air, oxygen or 4% carbon dioxide. Inspired respiratory minute volume was determined for each breath. Ventilation increased suddenly in the first breath with minimal changes in end-expiratory carbon dioxide tension and respiratory exchange ratio to a rate that remained constant for 20 seconds before increasing further. The rate of carbon dioxide output was uniform during the first 20 seconds. A 12% grade did not increase ventilation or oxygen uptake during runs of 20 seconds, but in the first minute of recovery, ventilation was 64% greater than after level runs. Inhalation of oxygen inhibited ventilation by 24% in the 20-second periods before and after the end of a 60-second run. Inhalation of carbon dioxide begun at rest produced increments in ventilation and end-expiratory carbon dioxide tension that varied little during running and recovery. In the 20-second runs ventilation varied with speed but appeared independent of ultimate metabolic cost. Submitted on January 21, 1960

Use of respiratory quotients in assessment of aerobic work capacity

1962 ◽  
Vol 17 (1) ◽  
pp. 47-50 ◽  
Author(s):  
B. Issekutz ◽  
N. C. Birkhead ◽  
K. Rodahl
Keyword(s):  
Carbon Dioxide ◽  
Oxygen Uptake ◽  
Work Load ◽  
Work Capacity ◽  
Bicycle Ergometer ◽  
Carbon Dioxide Output ◽  
Ergometer Test ◽  
Aerobic Work Capacity ◽  
Bicycle Ergometer Test ◽  
Better Than

Oxygen uptake and carbon dioxide output were measured in 32 untrained subjects during exercise on the bicycle ergometer. It was shown that the work respiratory quotient (RQ) under standardized conditions can be used as a measure of physical fitness. ΔRQ (work RQ minus 0.75) increases logarithmically with the work load and maximal O2 uptake is reached at a ΔRQ value of 0.40. This observation offered the possibility of predicting the maximal O2 uptake of a person, based on the measurement of RQ during a single bicycle ergometer test at a submaximal load. For each work RQ between 0.95 and 1.15 a factor was presented, together with the aid of a simple equation, which gave a good approximation (generally better than ±10%) of the maximal O2 uptake.

scholarly journals A SYSTEM FOR THE CONTINUOUS MEASUREMENT OF OXYGEN UPTAKE AND CARBON DIOXIDE OUTPUT IN ARTIFICIALLY VENTILATED PATIENTS

1983 ◽  
Vol 55 (8) ◽  
pp. 791-800 ◽  
Author(s):  
A.M. HENDERSON ◽  
P.C. FORRESTER ◽  
R.F. ARMSTRONG ◽  
C.A. MOSSE ◽  
D. HALSALL
Keyword(s):  
Carbon Dioxide ◽  
Oxygen Uptake ◽  
Continuous Measurement ◽  
Carbon Dioxide Output ◽  
Ventilated Patients

Effect of exercise on acute postprandial glucose concentrations and interleukin-6 responses in sedentary and overweight males

2018 ◽  
Vol 43 (12) ◽  
pp. 1298-1306 ◽  
Author(s):  
Aaron Raman ◽  
Jeremiah J. Peiffer ◽  
Gerard F. Hoyne ◽  
Nathan G. Lawler ◽  
Andrew J. Currie ◽  
...  
Keyword(s):  
Glucose Tolerance ◽  
Oxygen Uptake ◽  
Intermittent Exercise ◽  
Venous Blood ◽  
Area Under The Curve ◽  
Peak Oxygen Uptake ◽  
Moderate Intensity ◽  
Oral Glucose ◽  
Moderate Intensity Exercise ◽  
Blood Samples

This study examined the effect of 2 forms of exercise on glucose tolerance and the concurrent changes in markers associated with the interleukin (IL)-6 pathways. Fifteen sedentary, overweight males (29.0 ± 3.1 kg/m2) completed 2 separate, 3-day trials in randomised and counterbalanced order. An oral glucose tolerance test (OGTT; 75 g) was performed at the same time on each day of the trial. Day 2 of each trial consisted of a single 30-min workload-matched bout of either high-intensity intermittent exercise (HIIE; alternating 100% and 50% of peak oxygen uptake) or continuous moderate-intensity exercise (CME; 60 % of peak oxygen uptake) completed 1 h prior to the OGTT. Venous blood samples were collected before, immediately after, 1 h after, and 25 h after exercise for measurement of insulin, C-peptide, IL-6, and the soluble IL-6 receptors (sIL-6R; soluble glycoprotein 130 (sgp130)). Glucose area under the curve (AUC) was calculated from capillary blood samples collected throughout the OGTT. Exercise resulted in a modest (4.4%; p = 0.003) decrease in the glucose AUC when compared with the pre-exercise AUC; however, no differences were observed between exercise conditions (p = 0.65). IL-6 was elevated immediately after and 1 h after exercise, whilst sgp130 and sIL-6R concentrations were reduced immediately after exercise. In summary, exercise was effective in reducing glucose AUC, which was attributed to improvements that took place between 60 and 120 min into the OGTT, and was in parallel with an increased ratio of IL-6 to sIL-6R, which accords with an increased activation via the “classical” IL-6 signalling pathway. Our findings suggest that acute HIIE did not improve glycaemic response when compared with CME.

scholarly journals Acute effect of exercise intensity and duration on acylated ghrelin and hunger in men

2017 ◽  
Vol 232 (3) ◽  
pp. 411-422 ◽  
Author(s):  
David R Broom ◽  
Masashi Miyashita ◽  
Lucy K Wasse ◽  
Richard Pulsford ◽  
James A King ◽  
...  
Keyword(s):  
Oxygen Uptake ◽  
Exercise Intensity ◽  
Acute Exercise ◽  
Acute Effect ◽  
Peak Oxygen Uptake ◽  
Moderate Intensity ◽  
Acylated Ghrelin ◽  
Gut Hormone ◽  
Vigorous Intensity ◽  
Healthy Males

Acute exercise transiently suppresses the orexigenic gut hormone acylated ghrelin, but the extent to which exercise intensity and duration determine this response is not fully understood. The effects of manipulating exercise intensity and duration on acylated ghrelin concentrations and hunger were examined in two experiments. In experiment one, nine healthy males completed three, 4-h conditions (control, moderate-intensity running (MOD) and vigorous-intensity running (VIG)), with an energy expenditure of ~2.5 MJ induced in both MOD (55-min running at 52% peak oxygen uptake (V.O2peak)) and VIG (36-min running at 75% V.O2peak). In experiment two, nine healthy males completed three, 9-h conditions (control, 45-min running (EX45) and 90-min running (EX90)). Exercise was performed at 70% V.O2peak. In both experiments, participants consumed standardised meals, and acylated ghrelin concentrations and hunger were quantified at predetermined intervals. In experiment one, delta acylated ghrelin concentrations were lower than control in MOD (ES = 0.44, P = 0.01) and VIG (ES = 0.98, P < 0.001); VIG was lower than MOD (ES = 0.54, P = 0.003). Hunger ratings were similar across the conditions (P = 0.35). In experiment two, delta acylated ghrelin concentrations were lower than control in EX45 (ES = 0.77, P < 0.001) and EX90 (ES = 0.68, P < 0.001); EX45 and EX90 were similar (ES = 0.09, P = 0.55). Hunger ratings were lower than control in EX45 (ES = 0.20, P = 0.01) and EX90 (ES = 0.27, P = 0.001); EX45 and EX90 were similar (ES = 0.07, P = 0.34). Hunger and delta acylated ghrelin concentrations remained suppressed at 1.5 h in EX90 but not EX45. In conclusion, exercise intensity, and to a lesser extent duration, are determinants of the acylated ghrelin response to acute exercise.

Changes in Ventilation, Oxygen Uptake, and Carbon Dioxide Output during Recovery from Isoflurane Anesthesia

1989 ◽  
Vol 70 (5) ◽  
pp. 737-741 ◽  
Author(s):  
M. J. Clofolo ◽  
F. Clergue ◽  
C. Devillers ◽  
M. Ben Ammar ◽  
P. Viars
Keyword(s):  
Carbon Dioxide ◽  
Oxygen Uptake ◽  
Carbon Dioxide Output ◽  
Isoflurane Anesthesia

Dependence of mitosis and respiration in roots upon oxygen tension

1961 ◽  
Vol 154 (954) ◽  
pp. 109-129 ◽  
Keyword(s):  
Carbon Dioxide ◽  
Oxygen Uptake ◽  
Oxygen Tension ◽  
Oxygen Requirement ◽  
Anaerobic Conditions ◽  
Root Tips ◽  
Carbon Dioxide Output ◽  
Lower Oxygen ◽  
Oxygen Tensions ◽  
The Relationship

Excised pea-root tips were incubated for 4 h in gas mixtures containing 0.00001 to 100% oxygen, in order to determine the effect upon mitosis. Below 0.0005% oxygen, mitosis was completely arrested. Between 0.001 and 0.02% oxygen, cells initially in mitosis completed division, but no more cells started dividing. Between 0.05 and 0.2% oxygen, cells initially in interphase entered division, but did not finish. Above 0.5% oxygen, all cells not prevented from dividing by excision finished division within 4 h. After exposure to 0.05% oxygen for 4 h, an excessive proportion of cells was found in prophase; in 0.1% oxygen an excess of metaphases, and in 0.2% oxygen an excess of telophases resulted. The oxygen uptake and carbon dioxide output of root tips were measured in a range of oxygen tensions and in anaerobic conditions. The relationship between oxygen uptake and oxygen tension was hyperbolic; a half maximum rate of oxygen uptake was obtained at about 10% oxygen. It was concluded that the respiration of root tips was limited by slow diffusion of oxygen through the tissue. From the carbon dioxide output it was estimated that the amount of energy available to isolated root tips under anaerobic conditions was about 1% of that available under aerobic conditions. Possible mechanisms whereby extreme oxygen-lack could arrest mitosis were considered. It was shown that the arrest was not due to abolition of a gross supply of energy. No evidence was obtained as to what other mechanism might be operative. An hypothesis was formulated in an attempt to explain the complicated relationship between mitosis and oxygen tension. It was assumed that the visible phases of mitosis are immediately preceded by a phase with a higher requirement for oxygen than mitosis, and that preceding this is an earlier phase with a lower oxygen requirement than mitosis.

Sign in / Sign up

Export Citation Format

Share Document