| 1. |
- 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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| 2. |
- 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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| 3. |
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| 4. |
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| 5. |
- 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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| 6. |
- 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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| 7. |
- 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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| 8. |
- Schantz, Peter, 1954-, et al.
(författare)
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Can heart rate be used as an indicator of energy demands during commuter walking in a metropolitan area?
- 2016
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Konferensbidrag (refereegranskat)abstract
- IntroductionMeasuring the energetic demands of habitual commuter walking is essential to objectively relate to the impact that walking commuting can have on health. Hence, evaluating methods for such purpose is of great importance. Heart rate (HR) can possibly be used as long as the relationship between oxygen uptake (VO2) and HR is established in laboratory conditions and proven to be valid under field conditions. However, e.g. traffic, noise and exhaust fumes may introduce effects of e.g. stress that change the relationship in the field. Thus, the validity of the HR method needs to be scrutinized.MethodsVO2 and HR measurements during three submaximal exercise intensities on cycle ergometer were performed in the laboratory, as well as during normal commuting walking in the individuals´ normal field setting in Greater Stockholm, Sweden. 20 habitual commuter pedestrians (10 males and 10 females) aged 45 ± 7 yrs (mean ± SD) participated and validated stationary and portable metabolic systems (Rosdahl et al. 2010; 2016; Salier-Eriksson et al. 2012), and HR monitors were used. A comparison of the VO2 – HR relationship was made between the laboratory and field conditions.Results and Discussion Interpreting the heart rate levels during walking commuting from the VO2 – HR relationship in the laboratory resulted in oxygen uptakes that were 13.0 ± 10.6 % lower in males and 10.5 ± 11.5 % lower in females than the correct VO2 values. Thus, the study indicates that systematic differences between the laboratory and field conditions with respect to the VO2 – HR relationship are present in metropolitan conditions. The reason for these differences remains to be elucidated.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. |
- Schantz, Peter, 1954-, et al.
(författare)
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Estimating duration-distance relations in cycle commuting in the general population
- 2018
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Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 13:11
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Tidskriftsartikel (refereegranskat)abstract
- It is important to estimate the duration-distance relation in cycle commuting in the general population since this enables analyses of the potential for various public health outcomes. Therefore, the aim is to estimate this relation in the Swedish adult population of 2015. For that purpose, the first step was to establish it for adult male and female cycle commuters in Greater Stockholm, Sweden. Whether or not the slopes of these relations needed to be altered in order to make them representative of the general population was evaluated by comparing the levels of maximal oxygen uptake in samples of commuter cyclists and the population. The measure used was the maximal oxygen uptake divided by both the body weight and a cycle weight of 18.5 kg. The body weights in the population samples were adjusted to mirror relevant levels in 2015. Age adjustments for the duration–distance relations were calculated on the basis of the maximal oxygen uptake in the population samples aged 20–65 years. The duration-distance relations of the cycle commuters were downscaled by about 24–28% to mirror levels in the general population. The empirical formula for the distance (D, km) was based on duration (T, minutes) x speed (km/min) x a correction factor from cycle commuter to the general population x age adjustment (A, years). For the males in the general population the formula was: D = T x 20.76 km/h x 0.719 x (1.676 – 0.0147 x A). For females, the formula was: D = T x 16.14 km/h x 0.763 x (1.604 – 0.0129 x A). These formulas, combined with distributions of route distances between home and work in the population, enable realistic evaluations of the potential for different public health outcomes through cycle commuting.
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| 10. |
- Schantz, Peter, 1954-, et al.
(författare)
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The Heart Rate Method for Estimating Oxygen Uptake : Analyses of Reproducibility Using a Range of Heart Rates from Cycle Commuting
- 2019
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Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 14:7
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Tidskriftsartikel (refereegranskat)abstract
- Background. Monitoring aerobic exercise intensities of free-living physical activities is valuable for purposes such as education and research. The heart rate (HR) method, based on the linear relation between HR and oxygen uptake (VO2), is potentially valuable for this purpose. Three prerequisites are that the method is reproducible, and valid for the specific form of physical activity executed as well as under field conditions. The aim of this study is to evaluate reproducibility of the heart rate method in the laboratory. Methods. VO2 and HR measurements were made on two different occasions during three submaximal (model 1) plus a maximal exercise intensity (model 2) on a cycle ergometer in the laboratory. 19 habitual commuter cyclists (9 males and 10 females), aged 44 ± 3 years, were measured. The reproducibility of the estimated VO2, based on three levels of HR from commuting cycling and the regression equations from test and retest were analyzed. Differences between the two models were also studied. Results. For both models, there were no significant differences between test and retest in the constituents of the regression equations (y-intercept, slope and r-value). Neither were there any systematic differences in estimated absolute levels of VO2 between test and retest. The relative differences between test and retest, based on estimations from three different levels of HR, were 0.99 ± 11.0 (n.s.), 2.67 ± 6.48 (n.s.) and 3.57 ± 6.24% (p<0.05) for model 1, and 1.09 ± 10.6, 1.75 ± 6.43 and 2.12 ± 5.92% (all n.s.) for model 2. However, some large individual differences were seen in both models. There were no significant differences between the two models in the slopes, intercepts or r-values of the regression equations or in the estimated levels of VO2. Conclusion. The heart rate method shows good reproducibility on the group level in estimating oxygen consumption from HR-VO2 relations in the laboratory, and based on three levels of HR which are representative for cycle commuting. However, on the individual level, some large variations were seen.
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