Perceived exertion can be lower when exercising in field versus indoors.

PURPOSE: Studies indicate that the rated perceived exertion (RPE) during physical exercise can be lower in field environments than indoors. The environmental conditions of those studies are explored. Furthermore, we study if the same phenomenon is valid when cycling indoors versus in cycle commuting environments with high levels of stimuli from both traffic and suburban-urban elements. METHODS: Twenty commuter cyclists underwent measurements of heart rate (HR) and oxygen uptake ([Formula: see text]O2) and RPE assessments for breathing and legs, respectively, while cycling in both laboratory and field conditions. A validated mobile metabolic system was used in the field to measure [Formula: see text]O2. Three submaximal cycle ergometer workloads in the laboratory were used to establish linear regression equations between RPE and % of HR reserve (%HRR) and %[Formula: see text]O2max, separately. Based on these equations, RPE from the laboratory was predicted and compared with RPE levels at the participants' individual cycle commutes at equal intensities. The same approach was used to predict field intensities and for comparisons with corresponding measured intensities at equal RPE levels. RESULTS: The predicted RPE levels based on the laboratory cycling were significantly higher than the RPE levels in cycle commuting at equal intensities (67% of HRR; 65% of [Formula: see text]O2max). For breathing, the mean RPE levels were; 14.0-14.2 in the laboratory and 12.6 in the field. The corresponding levels for legs were; 14.0-14.2 and 11.5. The range of predicted field intensities in terms of %HRR and %[Formula: see text]O2max was 46-56%, which corresponded to median differences of 19-30% compared to the measured intensities in field at equal RPE. CONCLUSION: The cycle commuters perceived a lower exertion during their cycle commutes compared to ergometer cycling in a laboratory at equal exercise intensities. This may be due to a higher degree of external stimuli in field, although influences from other possible causes cannot be ruled out.

Pedestrians' Perceptions of Motorized Traffic Variables in Relation to Appraisals of Urban Route Environments.

It is important to examine how motorized traffic variables affect pedestrians along a gradient from rural to inner urban settings. Relations between pedestrians' perceptions of four traffic variables and appraisals of route environments as hindering-stimulating for walking as well as unsafe-safe for reasons of traffic, were therefore studied in the inner urban area of Stockholm, Sweden (n = 294). The pedestrians rated their perceptions and appraisals with the Active Commuting Route Environment Scale (ACRES). Correlation, multiple regression, and mediation analyses were used to study the relationships between the traffic variables and the outcome variables. Noise related negatively to both hindering-stimulating for walking, and to unsafety-safety for traffic reasons. Vehicle speed related negatively to unsafety-safety for traffic reasons. Furthermore, vehicle speed protruded as an important origin of the deterring effects of traffic among those who commute by foot. The study shows the value of both partial and simultaneous analyses of the effect of all four traffic variables in relation to outcome variables relevant for walking.

Perspectives on exercise intensity, volume, step characteristics and health outcomes in walking for transport.

Background: Quantification of movement intensity and energy utilization, together with frequency of trips, duration, distance, step counts and cadence, is essential for interpreting the character of habitual walking for transport, and its potential support of health. The purpose of the study is to illuminate this with valid methods and novel perspectives, and to thereby provide a new basis for characterizing and interpreting walking in relation to health outcomes. Methods: Habitual middle-aged commuting pedestrians (males = 10, females = 10) were investigated in the laboratory at rest and with maximal treadmill and cycle ergometer tests. Thereafter, levels of oxygen uptake, energy expenditure, ventilation, heart rate, blood lactate, rated perceived exertion, cadence, number of steps, duration, distance, and speed were recorded during the normal walking commute of each participant in Greater Stockholm, Sweden. The number of commutes per week over the year was self-reported. Results: Walking in the field demanded about 30% more energy per km compared to level treadmill walking. For both sexes, the walking intensity in field was about 46% of maximal oxygen uptake, and energy expenditure amounted to 0.96 kcal · kg- 1 · km- 1. The MET values (males: 6.2; females: 6.5) mirrored similar levels of walking speed (males: 5.7; females: 5.9 km · h- 1) and levels of oxygen uptake (males: 18.6; females: 19.5 mL · kg- 1 · min- 1). The average number of MET-hours per week in a typical month was 22 for males and 20 for females. This resulted in a total weekly energy expenditure of ~1,570 and 1,040 kcal for males and females, respectively. Over the year, the number of walking commutes and their accumulated distance was ~385 trips and 800 km for both sexes. Conclusion: Walking in naturalistic field settings demands its own studies. When males and females walk to work, their relative aerobic intensities and absolute energy demands for a given distance are similar. It is equivalent to the lower part of the moderate relative intensity domain. The combination of oxygen uptake, trip duration and frequency leads to high and sustained levels of MET-hours as well as energy expenditure per week over the year, with a clear health enhancing potential. Based on this study we recommend 6000 transport steps per day, or equivalent, during five weekdays, over the year, in order to reach optimal health gains.

Interchangeability and optimization of heart rate methods for estimating oxygen uptake in ergometer cycling, level treadmill walking and running.

BACKGROUND: The heart rate (HR) method enables estimating oxygen uptake (V̇O2) in physical activities. However, there is a paucity in knowledge about the interchangeability of this method when applied to cycling, walking and running. Furthermore, with the aim of optimization, there is a need to compare different models for establishing HR-V̇O2 relationships. METHODS: Twenty-four physically active individuals (12 males and 12 females) participated. For each participant, two models of HR-V̇O2 relationships were individually established in ergometer cycling, level treadmill walking and running. Model 1 consisted of five submaximal workloads, whereas model 2 included also a maximal workload. Linear regression equations were used to estimate V̇O2 at seven intensity levels ranging between 25 and 85% of heart rate reserve (HRR). The estimated V̇O2 levels were compared between the exercise modalities and models, as well as with data from a previous study. RESULTS: A high level of resemblance in estimated V̇O2 was noted between running and cycling as well as between running and walking, with both model 1 and model 2. When comparing walking and cycling, the V̇O2 levels for given intensities of %HRR were frequently slightly higher in walking with both models (range of significant differences: 5-12%). The variations of the estimated individual V̇O2 values were reduced when using model 2 compared to model 1, both between and within the exercise modalities. CONCLUSION: The HR method is optimized by more workloads and wider ranges. This leads to overall high levels of interchangeability when HR methods are applied in ergometer cycling, level treadmill walking and running.

Pedestrians' perceptions of route environments in relation to deterring or facilitating walking.

Background: Every walk takes place in a route environment, and it can play an important role in deterring or facilitating walking, and will always affect the environmental unwell-well-being of pedestrians. The aim of this study is to illuminate which the important route environmental variables are in this respect. The focus is, therefore, on pedestrians' perceptions of route environmental variables and how they relate to overall appraisals of route environments as hindering-stimulating for walking and unsafe-safe for reasons of traffic. Methods: Commuting pedestrians in the inner urban area of Stockholm, Sweden (n = 294, 49.5 ± 10.4 years, 77% women), were recruited via advertisements. They evaluated their commuting route environments using a self-report tool, the Active Commuting Route Environment Scale (ACRES). Correlation, multiple regression, and mediation analyses were used to study the relationships between the variables and the outcome variables. Results: Aesthetics and greenery appear to strongly stimulate walking, whereas noise, a proxy for motorized traffic, hinders it. Furthermore, aesthetics is positively related to traffic safety, whereas conflicts have the opposite role. Conflicts is an intermediate outcome, representing several basic environmental variables, some of which were directly and negatively related to unsafe-safe traffic. Conclusion: Route environmental variables appear to be potent factors in deterring or facilitating walking. This knowledge is of importance for policymakers and urban planners when designing route environments with the aim of attracting new pedestrians, and simultaneously stimulating those who already walk to keep on.

Overall health impacts of a potential increase in cycle commuting in Stockholm, Sweden.

AIMS: To estimate the overall health impact of transferring commuting trips from car to bicycle. METHODS: In this study registry information on the location of home and work for residents in Stockholm County was used to obtain the shortest travel route on a network of bicycle paths and roads. Current modes of travel to work were based on travel survey data. The relation between duration of cycling and distance cycled was established as a basis for selecting the number of individuals that normally would drive a car to work, but have a distance to work that they could bicycle within 30 minutes. The change in traffic flows was estimated by a transport model (LuTrans) and effects on road traffic injuries and fatalities were estimated by using national hospital injury data. Effects on air pollution concentrations were modelled using dispersion models. RESULTS: Within the scenario, 111,000 commuters would shift from car to bicycle. On average the increased physical activity reduced the one-year mortality risk by 12% among the additional bicyclists. Including the number of years lost due to morbidity, the total number of disability adjusted life-years gained was 696. The amount of disability adjusted life-years gained in the general population due to reduced air pollution exposure was 471. The number of disability adjusted life-years lost by traffic injuries was 176. Also including air pollution effects among bicyclists, the net benefit was 939 disability adjusted life-years per year. CONCLUSIONS: Large health benefits were estimated by transferring commuting by car to bicycle.

Heart Rate Methods Can Be Valid for Estimating Intensity Spectrums of Oxygen Uptake in Field Exercise.

PURPOSE: Quantifying intensities of physical activities through measuring oxygen uptake (V̇O2) is of importance for understanding the relation between human movement, health and performance. This can in principle be estimated by the heart rate (HR) method, based on the linear relationship between HR and V̇O2 established in the laboratory. It needs, however, to be explored whether HR methods, based on HR-V̇O2 relationships determined in the laboratory, are valid for estimating spectrums of V̇O2 in field exercise. We hereby initiate such studies, and use cycle commuting as the form of exercise. METHODS: Ten male and ten female commuter cyclists underwent measurements of HR and V̇O2 while performing ergometer cycling in a laboratory and a normal cycle commute in the metropolitan area of Stockholm County, Sweden. Two models of individual HR-V̇O2 relationships were established in the laboratory through linear regression equations. Model 1 included three submaximal work rates, whereas model 2 also involved a maximal work rate. The HR-V̇O2 regression equations of the two models were then used to estimate V̇O2 at six positions of field HR: five means of quintiles and the mean of the whole commute. The estimations obtained were for both models compared with the measured V̇O2. RESULTS: The measured quintile range during commuting cycling was about 45-80% of V̇O2max. Overall, there was a high resemblance between the estimated and measured V̇O2, without any significant absolute differences in either males or females (range of all differences: -0.03-0.20 L⋅min-1). Simultaneously, rather large individual differences were noted. CONCLUSION: The present HR methods are valid at group level for estimating V̇O2 of cycle commuting characterized by relatively wide spectrums of exercise intensities. To further the understanding of the external validity of the HR method, there is a need for studying other forms of field exercises.

Potential for reduced premature mortality by current and increased bicycle commuting: a health impact assessment using registry data on home and work addresses in Stockholm, Sweden.

OBJECTIVES: The study aims to make use of individual data to estimate the impact on premature mortality due to both existing commuter bicycling and the potential impact due to increased physical activity through shifting transport mode from car commuting to bicycling. METHODS: Using registry data on home and work addresses for the population of Stockholm County the shortest bicycling route on a network of bicycle paths and roads was retrieved. Travel survey data were used to establish current modes of commuting. The relation between duration of bicycling and distance bicycled within the general population in 2015 was established as a basis for identifying individuals that currently drive a car to work but were estimated to have the physical capacity to bicycle to work within 30 min. Within this mode-shift scenario from car-to-bike the duration of bicycling per week was estimated, both among current and potential bicycle commuters. The health impact assessment (HIA) on mortality due to bicycle commuting physical activity was estimated using the same relative risk as within the WHO Health Economic Assessment Tool. RESULTS: The current number of bicycle commuters were 53 000, and the scenario estimated an additional 111 000. Their mean bicycle distances were 4.5 and 3.4 km, respectively. On average these respective amounts of physical activity reduced the yearly mortality by 16% and 12%, resulting in 11.3 and 16.2 fewer preterm deaths per year. CONCLUSION: The HIA of transferring commuting by car to bicycle estimated large health benefits due to increased physical activity.

Perspectives on Exercise Intensity, Volume and Energy Expenditure in Habitual Cycle Commuting.

Background: Knowledge about exercise intensity and energy expenditure combined with trip frequency and duration is necessary for interpreting the character and potential influencing capacity of habitual cycle commuting on e.g., health outcomes. It needs to be investigated with validated methods, which is the purpose of this study. Methods: Ten male and 10 female middle-aged habitual commuter cyclists were studied at rest and with maximal exercise tests on a cycle ergometer and a treadmill in the laboratory. During their normal commute in the Stockholm County, Sweden, their oxygen uptake, heart rate, energy expenditure, ventilation, blood lactate, rated perceived exertion, number of stops, durations, route distances and cycling velocities were monitored with validated methods. The frequency of trips was self-reported. Results: The relative exercise intensity was 65% of maximal oxygen uptake, and the energy expenditure was 0.46 kcal per km and kg body weight for both sexes. Sex differences in MET-values (men, 8.7; women 7.4) mirrored higher levels of cycling speed (20%), body weight (29%), oxygen uptake (54%) and ventilation (51%) in men compared to women. The number of METhours per week during peak cycling season averaged 40 for the men and 28 for the women. It corresponded to a total energy expenditure of about 3,500 and 1,880 kcal for men and women, respectively. The number of trips per year was about 370, and the annual distance cycled was on average 3,500 km for men and 2,300 for women. Conclusion: Cycle commuting is characterized by equal relative aerobic intensity levels and energy requirements for a given distance cycled by men and women. Based on an overall evaluation, it represents a lower range within the vigorous intensity category. The combined levels of oxygen uptake, durations and trip frequencies lead to high levels of METhours and energy expenditure in both men and women during both peak cycling season as well as over the year. Overall, the study presents a novel basis for interpreting cycle commuting in relation to various health outcomes.

Are heart rate methods based on ergometer cycling and level treadmill walking interchangeable?

INTRODUCTION: The heart rate (HR) method is a promising approach for evaluating oxygen uptake ([Formula: see text]), energy demands and exercise intensities in different forms of physical activities. It would be valuable if the HR method, established on ergometer cycling, is interchangeable with other regular activities, such as level walking. This study therefore aimed to examine the interchangeability of the HR method when estimating [Formula: see text] for ergometer cycling and level treadmill walking in submaximal conditions. METHODS: Two models of [Formula: see text] regression equations for cycle ergometer exercise (CEE) and treadmill exercise (TE) were established with 34 active commuters. Model 1 consisted of three submaximal intensities of ergometer cycling or level walking, model 2 included also one additional workload of maximal ergometer cycling or running. The regression equations were used for estimating [Formula: see text] with seven individual HR values based on 25-85% of HR reserve (HRR). The [Formula: see text] estimations were compared between CEE and TE, within and between each model. RESULTS: Only minor, and in most cases non-significant, average differences were observed when comparing the estimated [Formula: see text] levels between CEE and TE. Model 1 ranged from -0.4 to 4.8% (n.s.) between 25-85%HRR. In model 2, the differences between 25-65%HRR ranged from 1.3 to -2.7% (n.s.). At the two highest intensities, 75 and 85%HRR, [Formula: see text] was slightly lower (3.7%, 4.4%; P < 0.05), for CEE than TE. The inclusion of maximal exercise in the [Formula: see text] relationships reduced the individual [Formula: see text] variations between the two exercise modalities. CONCLUSION: The HR methods, based on submaximal ergometer cycling and level walking, are interchangeable for estimating mean [Formula: see text] levels between 25-85% of HRR. Essentially, the same applies when adding maximal exercise in the [Formula: see text] relationships. The inter-individual [Formula: see text] variation between ergometer cycling and treadmill exercise is reduced when using the HR method based on both submaximal and maximal workloads.

The heart rate method for estimating oxygen uptake: analyses of reproducibility using a range of heart rates from commuter walking.

BACKGROUND: The heart rate method, based on the linear relation between heart rate and oxygen uptake, is potentially valuable to monitor intensity levels of physical activities. However, this depends not least on its reproducibility under standard conditions. This study aims, therefore, to evaluate the reproducibility of the heart rate method in the laboratory using a range of heart rates associated with walking commuting. METHODS: On two different days, heart rate and oxygen uptake measurements were made during three submaximal (model 1) and a maximal exercise intensity (model 2) on a cycle ergometer in the laboratory. 14 habitual walking commuters participated. The reproducibility, based on the regression equations from test and retest and using three levels of heart rate from the walking commuting, was analyzed. Differences between the two models were also analyzed. 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 for either model. However, some rather large individual differences were seen in both models. Furthermore, no significant differences were seen between the two models in slopes, intercepts and r values of the regression equations or in the estimated VO2. CONCLUSION: The heart rate method shows good reproducibility on the group level in estimating oxygen consumption from heart rate-oxygen uptake relations in the laboratory, and based on three levels of heart rate which are representative for walking commuting.

The heart rate method for estimating oxygen uptake: Analyses of reproducibility using a range of heart rates from cycle commuting.

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. 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. 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. 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.

Correction: Estimating duration-distance relations in cycle commuting in the general population.

[This corrects the article DOI: 10.1371/journal.pone.0207573.].

Correction: Correction: Estimating duration-distance relations in cycle commuting in the general population.

[This corrects the article DOI: 10.1371/journal.pone.0218221.].

Estimating duration-distance relations in cycle commuting in the general population.

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 establishit 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) · speed (km/min) · a correction factor from cycle commuter to the general population · age adjustment (A, years). For the males in the general population the formula was: D = T · 20.76 km/h · 0.719 · (1.676-0.0147 · A). For females, the formula was: D = T · 16.14 km/h · 0.763 · (1.604-0.0129 · 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.

Distance, Duration, and Velocity in Cycle Commuting: Analyses of Relations and Determinants of Velocity.

Background: The distance, duration, and velocity of cycling for transport purposes are used in health economic assessments, epidemiological studies, traffic modelling, and planning. It is therefore of value to determine relevant levels for them, and analyze how they relate, as well as to what extent other relevant variables may affect cycling velocities. 1661 cycle commuters (34% males) in Greater Stockholm, Sweden have been studied for that purpose. Methods: The participants were recruited with advertisements. They received questionnaires and individually adjusted maps to draw their normal cycling route. Route distances were measured by a criterion method. Age, sex, weight, height, and cycling durations to work were self-reported. The commuting routes were positioned in relation to inner urban and/or suburban-rural areas. Linear multiple regression analyses were used. Results: Cycling speeds were positively related to commuting distances or durations, being male, of younger age, having higher body weight but lower body mass index (BMI), and using the last digits 1-4 or 6-9 in duration reports (as compared to 0 and 5), as well as cycling in suburban (versus inner urban) areas. Conclusions: The study provides new knowledge about how distance and duration, as well as other factors, relate to the velocity of commuter cycling. It thereby enables the use of more appropriate input values in, for instance, health economic assessments and epidemiological health studies.

Impacts on air pollution and health by changing commuting from car to bicycle.

Our study is based on individual data on people's home and work addresses, as well as their age, sex and physical capacity, in order to establish realistic bicycle-travel distances. A transport model is used to single out data on commuting preferences in the County Stockholm. Our analysis shows there is a very large potential for reducing emissions and exposure if all car drivers living within a distance corresponding to a maximum of a 30min bicycle ride to work would change to commuting by bicycle. It would result in >111,000 new cyclists, corresponding to an increase of 209% compared to the current situation. Mean population exposure would be reduced by about 7% for both NOx and black carbon (BC) in the most densely populated area of the inner city of Stockholm. Applying a relative risk for NOx of 8% decrease in all-cause mortality associated with a 10µgm-3 decrease in NOx, this corresponds to >449 (95% CI: 340-558) years of life saved annually for the Stockholm county area with 2.1 million inhabitants. This is more than double the effect of the reduced mortality estimated for the introduction of congestion charge in Stockholm in 2006. Using NO2 or BC as indicator of health impacts, we obtain 395 (95% CI: 172-617) and 185 (95% CI: 158-209) years of life saved for the population, respectively. The calculated exposure of BC and its corresponding impacts on mortality are likely underestimated. With this in mind the estimates using NOx, NO2 and BC show quite similar health impacts considering the 95% confidence intervals.

Active Commuting Behaviors in a Nordic Metropolitan Setting in Relation to Modality, Gender, and Health Recommendations.

Active commuting between home and place of work or study is often cited as an interesting source of physical activity in a public health perspective. However, knowledge about these behaviors is meager. This was therefore studied in adult active commuters (n = 1872) in Greater Stockholm, Sweden, a Nordic metropolitan setting. They received questionnaires and individually adjusted maps to draw their normal commuting route. Three different modality groups were identified in men and women: single-mode cyclists and pedestrians (those who only cycle or walk, respectively) and dual-mode commuters (those who alternately walk or cycle). Some gender differences were observed in trip distances, frequencies, and velocities. A large majority of the commuting trip durations met the minimum health recommendation of at least 10-minute-long activity bouts. The median single-mode pedestrians and dual-mode commuters met or were close to the recommended weekly physical activity levels of at least 150 minutes most of the year, whereas the single-mode cyclists did so only during spring-mid-fall. A high total number of trips per year (range of medians: 230-390) adds to the value in a health perspective. To fully grasp active commuting behaviors in future studies, both walking and cycling should be assessed over different seasons and ideally over the whole year.

Exploring bikeability in a suburban metropolitan area using the Active Commuting Route Environment Scale (ACRES).

BACKGROUND AND AIM: Commuting by bicycle could contribute to public health, and route environments may influence this behaviour. Therefore, the aim of this study is to assess the potential associations between appraisals of the overall route environment as hindering or stimulating for bicycle commuting, with both perceptions of commuting route environmental factors in a suburban area and background factors. METHODS: The Active Commuting Route Environment Scale (ACRES) was used for the assessment of bicycle commuters' perceptions and appraisals of their route environments in the suburban parts of Greater Stockholm, Sweden. A simultaneous multiple regression analysis was used to assess the relationship between the outcome variable whether the overall route environment hinders or stimulates bicycle commuting and environmental factors (e.g., exhaust fumes, speeds of motor vehicles, greenery), as well as background factors (sex, age, education, income) as predictor variables. RESULTS AND CONCLUSIONS: The results indicate that in suburban areas, the factors aesthetics, greenery and bicycle paths seem to be, independently of each other, stimulating factors for bicycle commuting. On the other hand, flows of motor vehicles, noise, and low "directness" of the route seem to be hindering factors. A comparison of these results with those obtained from an inner urban area points to the importance of studying different types of built-up areas separately.

Physical activity and the perceived neighbourhood environment - looking at the association the other way around.

The association between physical activity (PA) and variables of the perceived environment mainly originate from cross-sectional studies that introduced the idea that the environment influences the PA level of residents. However, the direction of cause and effect has not been solved with finality. The aim of this study was to investigate whether residents' perception of their proximate environment differs depending on their level of PA in transport and recreation. We conducted a cross-sectional survey with residents of six different parts of the city of Cologne, Germany. The sample of 470 adults (52.8% females; mean age = 35.5 ± 13.8 years) filled in the Global Physical Activity Questionnaire (GPAQ), as well as the European Environmental Questionnaire ALPHA. To distinguish between residents with "low" and "high" PA, we split the samples into two on the basis of the specific median in transport- and recreation-related PA. In the "high" vs. "low" PA group of the overall sample, we noted 4%-16% more "PA favourable" environmental perceptions in seven of the 15 environmental variables. Multiple linear regression analyses were performed to investigate associations of socio-demographic correlates and transport- and recreation-related PA on the dependent variables of the environmental perception. In this case, levels of PA were significant predictors for eight of the 15 items concerning environmental perceptions. Thus, the present study introduces the idea that residents with higher levels of transport and recreational PA may perceive their environment in a more "PA-favourable" way than residents with lower levels.