| 1. |
- Ainegren, Mats, 1963-, et al.
(författare)
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Breathing resistance in automated metabolic systems is high in comparison with the Douglas Bag method and previous recommendations
- 2018
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Ingår i: Proceedings of the Institution of Mechanical Engineers, Part P. - : SAGE Publications. - 1754-3371. ; 232:2, s. 122-130
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Tidskriftsartikel (refereegranskat)abstract
- The purpose of this study was to investigate the resistance (RES) to breathing in metabolic systems used for the distribution and measurement of pulmonary gas exchange. A mechanical lung simulator was used to standardize selected air flow rates ( , L/s). The delta pressure (∆p, Pa) between ambient air and the air inside the equipment was measured in the breathing valve’s mouthpiece adapter for four metabolic systems and four types of breathing valves. RES for the inspiratory and expiratory sides was calculated as RES = ∆p / , Pa/L/s. The results for RES showed significant (p < 0.05) between-group variance among the tested metabolic systems, as well as the breathing valves and between most of the completed . The lowest RES among the metabolic systems was found for a Douglas Bag system, with approximately half of the RES compared to the automated metabolic systems. The automated systems were found to have higher RES already at low in comparison to previous recommendations. For the hardware components, the highest RES was found for the breathing valves while the lowest RES was found for the hoses. Conclusion: The results showed that RES in metabolic systems can be minimized through conscious choices of system design and hardware components.
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| 2. |
- Henriksson, Jan, et al.
(författare)
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Per-Olof Åstrand : Nekrolog
- 2015
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Annan publikation (populärvet., debatt m.m.)abstract
- Nekrolog över Per-Olof ÅstrandProfessor emeritus Per-Olof Åstrand har avlidit i en ålder av 92 år. Hans närmaste anhöriga är makan Irma och barnen Elin och Per med familjer.Per-Olof Åstrand föddes i Bredaryd i Småland den 21 oktober 1922, och avled den 2 januari 2015 i Näsby Park norr om Stockholm. Efter värnplikt och beredskapstjänstgöring i pansartrupperna under andra världskriget kom han 1944 till Kungl. Gymnastiska Centralinstitutet (GCI/GIH) för studier till gymnastiklärare. Vid sluttentamen i fysiologi var hans svar så avancerade att den ansvarige läraren bad professorn, Erik Hohwü Christensen, att rätta dem. Kort därefter fick GCI:s fysiologiska institution en ny amanuens.Efter gymnastikdirektörsexamen 1946 följde läkarstudier, och parallellt med dessa inleddes avhandlingsarbetet ”Experimental studies of physical working capacity in relation to sex and age”, som försvarades 1952. Genom detta utvecklades en metodik för att mäta maximal syreupptagning. Det blev en avgörande variabel att relatera till i hans senare forskning om den cirkulatoriska och respiratoriska anpassningen till fysiskt arbete och träning. Det submaximala konditionstest som P.-O., och hans blivande hustru Irma Ryhming, publicerade år 1954 bidrog till att göra GCI känt över världen. Det finns fog att benämna honom som ”den vetenskapligt baserade konditionsträningens fader”. 1970 blev han professor i kroppsövningarnas fysiologi vid GIH.P.-O. visade tidigt ett stort intresse för undervisning, och många mötte honom i populärvetenskapliga skrifter såsom ”Kondition och hälsa” och ”Bättre kondition”, men det var genom den omfattande läroboken ”Textbook of Work Physiology: Physiological Bases for Exercise”, skriven tillsammans med Kaare Rodahl, som han blev det riktigt stora namnet inom internationell arbetsfysiologi. Där framträdde holisten Åstrand med en bredd och ett djup som ingen förr hade fångat och skrivit fram. Denna bok, P.-O:s pedagogiska förmåga och engagemang har haft avgörande betydelse för många studenter och kolleger.Hans gärningar gjorde honom till ledamot i många lärda sällskap och hedersdoktor vid ett antal universitet ute i världen. Därtill var han en hedersman, med en personlighet präglad av en stor omtanke, slagkraftig humor och generös spiritualitet, ofta med inslag av en särpräglad musikalisk förmåga. För oss som studenter och lärare vid GIH kom samvaron med P.-O. ofta att formas till högtidsstunder. En legendar har nu lämnat oss i djupaste sorg, men också i tacksamhet över allt han bidrog med i våra liv.Jan HenrikssonHans RosdahlPeter SchantzHarriet Wallberg
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| 3. |
- Lövenheim, Boel, et al.
(författare)
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Health risk assessment of reduced air pollution exposure when changing commuting by car to bike
- 2016
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Konferensbidrag (refereegranskat)abstract
- In this study we have assessed the reduction in traffic emissions and population exposure assuming all potential car commuters would switch to biking if they live within 30 minute travel by bike. The scenario would result in more than 100 000 new bikers and due to the reduced traffic emissions 42 premature deaths would be avoided per year. This is almost twice as large effect as the congestion tax in Stockholm. Introduction Regular physical activity has important and wide-ranging health benefits including reduced risk of chronic disease, and physical inactivity is mentioned as perhaps the most important public health problem of the 21st century. At the same time, the direct effects of traffic emissions is a major health problem. Transferring commuting by car to bike will increase physical activity and reduce emissions and reduce population exposure to traffic pollution. The exposure of commuters will also change; new bikers may get higher exposure whilst old bikers and car drivers may get lower exposures, depending on commuting route and distance. Methodology In this study we have calculated the potential number of car-to-bike switching commuters depending on distance, travel time, age of commuters, etc. We have made calculations for a 30-minute biking scenario, i.e. transferring all car commuters to bike if their travel time by bike is less than or equal to 30 minutes. The commuting distance depends on age and sex. For the travel and traffic modelling the LuTrans model was used. It includes all different modes of travel; walking, bicycling, public transport systems and car traffic. The model was developed based on travel survey data and is regularly calibrated using traffic counts. Emissions from road traffic were calculated based on HBEFA 3.2. A Gaussian dispersion model was used estimate exposures over the county of Stockholm. Results The 30 min scenario resulted in 106 881 more bikers, an increase of 2.6 times compared to base scenario. Of all bikers 50% were men and the mean age of all bikers was 42. The traffic emissions of NOx was reduced by up to 7%. Up to 20% reduction in traffic contribution to NOx concentrations was calculated as shown in Figure 1. The mean reduction in concentration for the whole area is 6% and the largest occur were most people live.The population weighted mean NOx concentration for 1.6 million people in Greater Stockholm is estimated to be reduced by 0.41 μg m-3. Assuming that the premature mortality is reduced by 8% per 10 μg m-3 (Nafstad et al., 2004), this corresponds to 42 avoided premature deaths every year or 514 gained life years gained. This is even somewhat more beneficial than the effects of the congestion charge in Stockholm (Johansson et al., 2009), which was estimated to save 27 premature deaths per year. The gain in reduced mortality is almost as large as the gain in health of the increased physical activity. Conclusions Transferring car commuters to bike is not only beneficial for the physical activity, but will also lead to reduced traffic emissions and reduced population exposure. Our estimates show that it may be even more beneficial for mortality due to air pollution exposure than the congestion charge in Stockholm. Acknowledgement This project was funded by the Swedish Research Council for Health, Working life and Welfare. References Johansson, C., Burman, L., Forsberg, B. 2009. The effects of congestions tax on air quality and health. Atmos. Environ. 43, 4843-4854.Nafstad, P., Lund Håheim, L., Wisloeff, T., Gram, G., Oftedal, B., Holme, I., Hjermann, I. and Leren, P. 2004. Urban Air Pollution and Mortality in a Cohort of Norwegian Men. Environ. Health Perspect. 112, 610-615.
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| 4. |
- Nilsson, Johnny, 1950-, et al.
(författare)
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Contribution of leg muscle forces to paddle force and kayak speed during maximal effort flat-water paddling
- 2016
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Ingår i: International Journal of Sports Physiology and Performance. - : Human Kinetics. - 1555-0265 .- 1555-0273. ; 11:1, s. 22-27
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Tidskriftsartikel (refereegranskat)abstract
- The purpose was to investigate the contribution of leg-muscle-generated forces to paddle force and kayak speed during maximal-effort flat-water paddling. Five elite male kayakers at national and international level participated. The participants warmed up at progressively increasing speeds and then performed a maximal-effort, nonrestricted paddling sequence. This was followed after 5 min rest by a maximal-effort paddling sequence with the leg action restricted—the knee joints “locked.” Left- and right-side foot-bar and paddle forces were recorded with specially designed force devices. In addition, knee angular displacement of the right and left knees was recorded with electrogoniometric technique, and the kayak speed was calculated from GPS signals sampled at 5 Hz. The results showed that reduction in both push and pull foot-bar forces resulted in a reduction of 21% and 16% in mean paddle-stroke force and mean kayak speed, respectively. Thus, the contribution of foot-bar force from lower-limb action significantly contributes to kayakers’ paddling performance.
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| 5. |
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| 6. |
- Rosdahl, Hans, et al.
(författare)
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Physiology of canoeing
- 2019. - 1
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Ingår i: Canoeing. - Hoboken, NJ : Wiley-Blackwell. - 9781119097204 ; , s. 47-61
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Bokkapitel (övrigt vetenskapligt/konstnärligt)
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| 7. |
- Rosdahl, Hans, et al.
(författare)
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Validation of data collected with mobile metabolic measurement systems over time during active commuting
- 2016
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Konferensbidrag (refereegranskat)abstract
- IntroductionWith the aim of attaining valid descriptions of metabolic demands during active commuting in greater Stockholm new approaches have been used. We have previously reported evaluations of a mobile metabolic measurement system both in the laboratory (Rosdahl et al. 2010) and during simulated field conditions, including check of stability over time (Salier-Eriksson et al. 2012). However, to be confident with the validity of the metabolic data collected over time during mobile field conditions we have used new approaches. MethodsDuring the period of data collection in the field with the mobile metabolic system (Oxycon Mobile, JLAB 5.21, CareFusion, Germany) this was controlled once by the manufacturer and 11 times in our own laboratory using a commercially available metabolic calibrator (Vacumed, syringe No.1750 and mass flow controller No. 17052, Ventura, CA, USA). On each occasion VO2 and VCO2 were checked between 1 - 4 L/min with the corresponding VE at 40-160 L/minute and tidal volume at 2 L. The calibration information (offset, gain and delay time) from the O2 and CO2 analyzers and volume sensor, being collected pre and post the field commuting tests, was analyzed. Additionally, the results of each experiment was critically examined in several means including an inspection of parallelism in heart rate and VO2. Results and DiscussionAs examined with the metabolic calibrator, all parameters (VO2, VCO2, RER and VE) measured by the mobile metabolic system were in general well within the boundaries of acceptance. Adequate stability of the O2 and CO2 analyzers and volume sensors for the time duration of each experiment was confirmed by small differences in the pre- and post-calibration factors. Based on two researchers´ ocular inspections of heart rate and oxygen uptake recordings during active commuting, all but one were rated as generally parallel, and thus passed this type of check of the field measurements. Overall, the present investigation favors that data collected over time with a mobile metabolic system can be validated by a combination of metabolic calibrator measurements, analyses of calibration information and a critical examination of the variables from each single measurement.ReferencesRosdahl, H., Gullstrand, L., Salier Eriksson, J., Johansson, P. & Schantz, P. 2010. Evaluation of the Oxycon Mobile metabolic system against the Douglas bag method. Eur J Appl Physiol 109 (2):159-71.Salier Eriksson, J., Rosdahl, H. & Schantz, P. 2012. Validity of the Oxycon Mobile metabolic system under field measuring conditions. Eur J Appl Physiol, 112 (1): 345-355.Huszczuk, A., Whipp, B.J and Wasserman, K. 1990. A respiratory gas exchange simulator for routine calibration in metabolic studies. Eur. Respir. J. 3:465-468.
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| 8. |
- Salier Eriksson, Jane, et al.
(författare)
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Relationships between heart rate and oxygen uptake in laboratory conditions and in bicycling commuting
- 2016
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Konferensbidrag (refereegranskat)abstract
- Introduction. Measuring the energetic demands of habitual commuter cyclists is essential to create more accurate methods for measuring active commuting so as to be able to objectively determine the impact that cycle commuting can have on population health.Heart rate (HR) can be used as an indicator of aerobic processes while commuter cycling as long as the relationship between oxygen uptake (VO2) and HR is established in laboratory conditions. However in the field, environmental aspects might introduce effects of stress that change the relationship. Thus measurements need also to be performed in the field in order to explore the HR-VO2 relationship between the two conditions.Methods. Metabolic measurements were performed in the laboratory as well as in the field using 20 habitual commuter cyclists (10 males and 10 females) aged 44 ± 3 yrs. A validated stationary as well as a portable metabolic system was used (Rosdahl et al. 2010; 2016; Salier-Eriksson et al. 2012). A comparison was made between the laboratory and field conditions of the HR-VO2 relationship.Results and Discussion. Based on the average heart rate, the measured oxygen uptake was about 2.5 % lower (n.s.) than the expected levels based on the steady state HR-VO2 relationships in the laboratory. Thus, the results indicate that the HR-VO2 relationships in the field were comparable to those measured in the laboratory on a group level. However, relatively large individual differences were found.ReferencesRosdahl, H., Gullstrand, L., Salier Eriksson, J., Johansson, P. & Schantz, P. 2010. Evaluation of the Oxycon Mobile metabolic system against the Douglas bag method. Eur J Appl Physiol 109 (2):159-71.Rosdahl, H., Salier Eriksson, J. & Schantz, P. 2016. Validation of data collected with mobile metabolic measurement systems over time during active commuting. Proceedings of the 21st Annual Congress of The European College of Sport Sciences, Vienna, Austria, 6-8 July (Abstract). Salier Eriksson, J., Rosdahl, H. & Schantz, P. 2012. Validity of the Oxycon Mobile metabolic system under field measuring conditions. Eur J Appl Physiol, 112 (1): 345-355.
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| 9. |
- Salier Eriksson, Jane
(författare)
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The heart rate method for estimating oxygen uptake in walking and cycle commuting : Evaluations based on reproducibility and validity studies of the heart rate method and a portable metabolic system
- 2018
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Walking and cycling to work can contribute to population health, but more objective knowledge concerning exercise intensities, oxygen uptake and the metabolic demands of this physical activity is needed for this and other evaluations. To attain this, valid and reliable instruments are a requirement. The focus of this thesis was to evaluate whether the heart rate method can be used for this purpose. It involves establishing the relation between heart rate and oxygen uptake during ergometer cycling in laboratory conditions, and thereafter checking if the same relation exists during cycle or walking commuting in a metropolitan area.To accomplish this, a portable metabolic system was tested for validity and reliability in laboratory and field conditions and the reproducibility of the heart rate and oxygen uptake relation in the laboratory was evaluated. Furthermore, the heart rate and oxygen uptake relations during cycle and walking commuting was compared with those attained in the laboratory.The first two studies showed that a portable metabolic system is valid during laboratory and sustained field conditions. Studies 3 and 4 showed that the heart rate method with respect to the heart rate-oxygen uptake relationship is reliable on the group level for both walking and cycling commuters during repeated measures in the laboratory. The last two studies showed that applying the heart rate method during cycle commuting leads to valid levels of oxygen uptake on the group level for both males and females. Contrary to that, the measured levels of oxygen uptake in the field during walking commuting were on average 17% higher for males, and 13% higher for females than the values obtained with the heart rate method. For both walking and cycling commuters, the individual spread around the mean values was rather high, creating somewhat wide confidence intervals for the mean values.In summary, the heart rate method can be used for cycle commuters during their normal commuting conditions, while for pedestrians it is necessary to take into account that oxygen uptake per heart rate is higher while walking than that estimated from ergometer cycling in the laboratory.
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| 10. |
- Schantz, Peter, 1954-, et al.
(författare)
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An Overview, Description and Synthesis of Methodological Issues in Studying Oxygen Consumption during Walking and Cycling Commuting using a Portable Metabolic System (Oxycon Mobile).
- 2018. - 1
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- From the time of the independent discoveries of oxygen by Carl Wilhelm Scheele in Sweden and Joseph Priestly in England in the 1770s, there has been an ongoing chain of methodological developments, from the pioneering ones by Antoine Lavoisier until today, with the aim of measuring oxygen uptake and metabolic processes of man in motion (Mitchell and Saltin 2003). This historical development, has, not least during the last decades, also included both automated stationary and portable open-circuit metabolic measurement systems, which have been thoroughly reviewed recently (Macfarlane 2017; Ward 2018; Taylor et al. 2018). When two of the present authors (PS and HR) were trained as exercise physiologists, the golden standard method in this respect, the Douglas bag method (DBM), was the only, or the predominantly used method at our laboratory. In the 1990s, automated stationary open-circuit metabolic measurement systems started to be used, and HR evaluated some of them using DBM. He noted that it was not apparent that one could rely on the data produced in these “black box” systems. Still they have been used in many laboratories, and possibly there are a number of scientific articles based on them which might hold invalid data. One comment along that line was sent in 2001 as an e-mail from our teacher, professor emeritus Per-Olof Åstrand to an American colleague (Appendix 1). It ended with: “I have observed many odd data in the literature which can be explained as a consequence of uncritical use of modern, fancy electronic equipments without serious and competent evaluation of their accuracy”.For HR, these kind of experiences during the 1990s became an important impetus to develop a refined system for the Douglas bag method at the Laboratory for Applied Sport Sciences at the Swedish School for Sport and Health Sciences, GIH, in Stockholm, Sweden. That process was undertaken in close collaboration with Lennart Gullstrand at the Elite Sports Centre, The Swedish Sports Confederation, Bosön, Lidingö, Sweden. This text builds on that system, and many other developmental steps that have been taken since then. They have been applied to study a number of issues related to walking and cycle commuting, as part of the multidisciplinary research project on Physically Active Commuting in Greater Stockholm (PACS) at GIH. For its overall aims, see: www.gih.se/pacsOne of the aims is to characterize the physiological demands of walking and cycle commuting in relation to absolute and relative demands of oxygen uptake (VO2). This is of interest in itself for understanding the nature of the physical activity during active commuting. Combined with other kinds of data one aim was also to better understand the potential health effects of active commuting. An important issue in this respect was to scrutinize whether the heart rate method for estimating VO2 (Berggren & Hohwü Christensen 1950) would be a reliable and valid method during cycle or walking commuting.To reach these goals we needed to use an automated mobile metabolic system. However, we had to work for a much longer time than expected due to a surprising number of diverse methodological challenges in measurements of both VO2 and heart rate (HR). They had to be considered and evaluated through a series of validity studies and checks. Some of the issues could be foreseen and were rather straight forward to handle, whereas others were unexpected, and the strategies to handle them had to be developed step by step as they appeared during the research process. Here this process will be first introduced, then described in more or less detail, and in cases of less details, we instead refer to issues in more depth in original articles. Finally, a synthesis of all studies and their consequences is elaborated on at the end of this appendix.
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