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Carriage of Oxygen in Blood
Published in Peter Kam, Ian Power, Michael J. Cousins, Philip J. Siddal, Principles of Physiology for the Anaesthetist, 2020
Peter Kam, Ian Power, Michael J. Cousins, Philip J. Siddal
The partial pressures and contents of oxygen and carbon dioxide in arterial and venous blood are indicated in Table 18.1. The normal oxygen consumption per minute is 250 mL; the total amount of oxygen in the body is only approximately 1.5 L, and less than half is immediately available for use. Carbon dioxide production is 200 mL/min, and the total body content amounts to 120 L.
Oxygen Supply to Malignant Tumors
Published in Hans-Inge Peterson, Tumor Blood Circulation: Angiogenesis, Vascular Morphology and Blood Flow of Experimental and Human Tumors, 2020
Acute oxygen shortages were produced by removal of RBCs in tumor-bearing animals.2 Under these conditions, the malignant tumors improved the O2 removal ratios from the blood; however, the overall utilization of oxygen decreased. During a chronic shortage of O2 due to anemia or low blood flow, the oxygen consumption declined in proportion to the oxygen available.
Methods of nutritional assessment and surveillance
Published in Geoffrey P. Webb, Nutrition, 2019
The simplest way of measuring oxygen consumption (and carbon dioxide evolution) is to use a Douglas bag. This is a large plastic bag fitted with a two-way valve so that the subject who breathes through a mouthpiece attached to the valve sucks in air from the atmosphere and then blows it out into the bag. All of the expired air can be collected over a short period of time and then the volume and composition of this expired air can be measured. Knowing the composition of the inspired atmospheric air means that the subject’s oxygen consumption and carbon dioxide evolution can be calculated. Note that the collection period is limited to a few minutes even if the capacity of the bag is large (100 L).
Association between physical and mental health variables among software professionals working at home: a secondary analysis
Published in International Journal of Occupational Safety and Ergonomics, 2022
Prabhu Muniswamy, Irene Grace Peter, Varadayini Gorhe, Baskaran Chandrasekaran
The baseline characteristics including the demographicvariables and physical and mental health variables are presented in Table 1. Fifty-two (65%) respondents were male. Males had an average maximal oxygen consumption of 46.05 ± 4.17 ml/kg/min while females had 39.82 ± 4.20 ml/kg/min. Females were found to have a lower maximal oxygen consumption (−6.23 [−8.17 to −4.28] ml/kg/min) than males. We found that majority of the participants (n = 76, 95%) did not meet the global guidelines of 30 min of PA per day. Average daily sitting time was found to be 9.58 ± 2.5 h regardless of work or non-work day. We did not observe statistical difference in the average daily sitting time, PA levels or sleep duration between males and females. We found a significant difference (t = −10.17; p < 0.001) in total daily sitting time between work days (417.82 ± 87.08 min) and non-work days (593.51 ± 151.67 min) whereas we did not find a significant difference in PA levels between work days (16.02 ± 4.18 min) and non-work days (15.76 ± 2.63 min). Total daily sitting time during non-work days was –175.69 ± 154.50 min higher than total daily sitting time during work days. We found a higher prevalence of stress (n = 43, 53.75%), anxiety (n = 60, 75%) and depression (n = 49, 61.25%) in the study participants. Females were found to have higher levels of stress (10%), anxiety (11%) and depression (6%) when compared to males. The baseline physical and mental health variables are presented in Table 1.
Energy consumption and cost during walking with different modalities of assistance after stroke: a systematic review and meta-analysis
Published in Disability and Rehabilitation, 2020
Nina Lefeber, Sam De Buyzer, Nikkie Dassen, Emma De Keersmaecker, Eric Kerckhofs, Eva Swinnen
The energy requirements of walking can be assessed by respiratory gas analysis [4]. After a few minutes of submaximal walking at constant workload, the amount of oxygen consumption reaches a plateau and achieves a steady-state condition. At this point, the oxygen consumption measured expresses the energy consumption required for walking – expressed in millilitres oxygen per kilogram bodyweight per minute (ml/kg/min), or converted to Joules per kilogram bodyweight per minute (J/kg/min). Since energy consumption depends on the walking speed (e.g., comfortable walking speed [CWS] or maximal walking speed [MWS]) [5,6], another common expression is energy cost. Energy cost refers to the amount of oxygen consumed per distance walked, and is obtained by dividing energy consumption by walking speed (ml/kg/m or J/kg/m) [1]. Both outcomes can be expressed as gross (total amount) or net (amount above resting level) measures.
Energy expenditure estimation of a moderate-intensity strength training session
Published in Cogent Medicine, 2020
Gustavo Allegretti João, Daniel Rodriguez, Lucas D. Tavares, Roberta L. Rica, Nelson Cavas Júnior, Victor M. Reis, Francisco L. Pontes Junior, Julien S. Baker, Danilo S. Bocalini, Aylton Figueira Júnior
Brown et al. (1994) analyzed the oxygen consumption associated with EE during the deadlift exercise. The regression equation developed (R = 0.90) was used to predict oxygen consumption (liters of oxygen) during exercise. Other studies have also used oxygen uptake converted to calories to predict EE. Byrd et al. (Byrd et al., 1998) examined the relationship between work done and EE during bench press exercise and the parallel squat exercise (Byrd et al., 1996). Oxygen consumption was measured by standard open-circuit spirometry, with conversion to caloric equivalents. The regression equation was calculated with external workload (kgm = multiplying the weight lifted (kg) x amount of repetitions (rep) x vertical distance of the bar). In summary, the prediction equation produced values of between R 0.91–0.95. Robergs et al. (2007) analyzed oxygen consumption using two exercises squat and bench press, in which a 5 minute steady-state per exercise set was performed and allowed for the development of 2 predictive equations, one for the bench press (R2 = 0.72) and one for the squat exercise (R2 = 0.65). Robergs et al. (2007) used intensities below 40% 1-RM with 21 repetitions and then extrapolated the values to higher intensities using the O2 deficit method as repeated by Reis et al. (Reis et al., 2017).