Moderate physical activity, including walking or cycling, offers a range of benefits for health and well-being [
1,
2]. However, until recently, where the physical activity took place received little attention. Although ecological models of health behavior consider characteristics of the physical environment, these tend to be defined very broadly, e.g., in terms of place of residence and accessibility of dedicated sports facilities such as swimming pools [
3]. However, research is lacking that compares the effect of exercise taking place in different settings. Simultaneously, there has been increasing recognition in the field of Environmental Psychology that exposure to natural environments such as parks and woodlands (“green environments”) and rivers and coastlines (“blue environments”) benefits health and well-being [
4,
5,
6,
7]. Given these two strands of evidence, efforts have begun to explore the potential benefits of undertaking physical activity in various settings. Put simply, might physical activity in natural settings be more beneficial than similar exercise in indoor gyms or urban settings? This question relates keenly to a recent paradigm shift that emphasises the role of affect in exercise behavior as opposed to cognitive factors [
8,
9]. While these researchers focus on the affect arising directly from the experience of physical exercise, the present paper extends this reasoning by investigating whether positive affect from exercise varies by the setting of the exercise.
1.1. Evidence of Interactive Effects
In a pioneering study, Pretty and colleagues [
10] investigated the interactive effects of viewing different (simulated) environments (pleasant and unpleasant, urban and natural, scenes) while engaging in physical activity in a laboratory setting, on a range of physiological and psychological outcomes. Results suggested that, compared to a control condition (a blank wall), viewing a pleasant rural scene while exercising on a treadmill led to a significant decrease in mean arterial blood pressure, whereas viewing an unpleasant urban scene led to a significant increase. Moreover, self-esteem was significantly higher following exercise while viewing pleasant rural and urban scenes than control exercise, suggesting that both physiological and psychological outcomes may be affected by the setting in which exercise takes place.
Since 2005 a sufficient body of work has been conducted to result in two systematic reviews of the potential interactive effects of physical activity across different environments. Thompson Coon
et al. [
11] compared the impacts on physical and mental wellbeing of physical activity indoors, mostly on treadmills, with physical activity undertaken in outdoor natural settings. A second review by Bowler
et al. [
12] focused more broadly on natural
versus non-natural settings, including indoor and outdoor urban environments, and active and passive exposure. Both reviews concluded that few studies in this area were well conducted, but they nonetheless came to broadly the same two conclusions.
First, they agreed that there was support for the notion that exposure to, and especially practice of physical activity in, natural environments leads to better affective outcomes, including increased feelings of revitalization, positive engagement and energy, and decreased negative affect, tension, confusion, anger and depression. This is consistent with earlier suggestions that natural environments promote stress reduction [
13,
14,
15,
16]. Second, there was little prior evidence of interactive effects of nature and physical activity on either physiological outcomes (e.g., heart rate or blood pressure) or cognitive processes (e.g., attention tasks).
Importantly, the reviews identified a number of gaps in the literature that require further research. For instance, most studies were conducted with convenience samples, primarily: “
college students, adult males, and physically active adults, and are not representative” ([
12], p. 7). Levels of physical activity and cardiovascular fitness tend to be highest in this age group [
17] and consequently it may be difficult to detect environmental effects on physiological outcomes. There is also evidence that connectedness with natural environments is lowest during adolescence and early adulthood [
18,
19] and therefore any effects of different environments might be weaker and less evident among this demographic.
Further, both reviews had difficulty identifying exactly what environments were being compared, both within and across studies: “
There is a limited variety of types of outdoor space utilized for physical activity and little descriptive information on the outdoor space provided in most papers” ([
11], p. 1764). Most studies were on “university campuses”, which presumably contain a mixture of buildings, roads and green space, while others were simply described as being “outdoors”. These limited descriptions, added to a small number of environment types used as comparators, make it difficult to construct a picture of the relative impacts of specific environments.
While examining physical activity across different environments, most studies also only monitored outcomes pre and post exercise (although see [
20,
21]). This is unfortunate as key changes may occur during the exercise period itself, but dissipate by the time of post-testing. Building on the circumplex model of affect [
22], which argues that affective states fall along the perimeter of a circle with two dimensions characterized by valence (positive-negative) and arousal/activation, Ekkekakis and colleagues [
23] developed a method for monitoring affective responses in terms of both valence and arousal at several times before, during and after exercise. Using this approach, Focht [
20] investigated changes in affect before, during and after a 10 min walk, either in the laboratory or “outdoors”, among a cohort of young female volunteers. Although both walks resulted in improvements in positive affect during and after the walks, the outdoor walk had a larger impact
during the walk.
Focht [
20] also asked participants how much they enjoyed the walk and their willingness to walk in “similar settings” in the future. These evaluative and intention related items are important in understanding how affective experiences during physical activity might translate into future behaviour, especially intentions to engage in further physical activity. As predicted, “outdoor” walking resulted in more positive evaluations and intentions to walk in similar settings again. However, as “outdoor” was defined as “a standardized route on sidewalks and walking paths in the area immediately surrounding the building” (p. 614) it remains unclear whether all kinds of outdoor environment have the same impact.
Although not explicitly mentioned in either review, none of the studies considered time perception during bouts of exercise in the different environments. The idea that people can experience a sense of flow [
24] during exercise is not new [
25]. What is novel is the possibility that it is easier to experience flow and lose track of time while exercising in a natural settings than in an indoor “Gym”. If natural settings are intrinsically fascinating and pleasurable [
26], and time passes more quickly when experiencing positive affective states [
27], then it should be easier for the mind to lose track of time in natural environments. A similar process might also apply for perceptions of effort, as measured by the Rate of Perceived Exertion scale (RPE, [
28,
29]). If people become immersed in an environment, not only might they lose track of time but they might also lose track of effort. This could be crucial because if people are likely to become more immersed in some environments than others, they may continue exercising for longer and harder without realizing it, with resulting benefits for health.
1.2. Current Research
Our aim was to explore the potential interactive effects between physical activity and various natural and non-natural settings by: (a) using a non-student sample of post-menopausal women; (b) using a laboratory study design to compare a range of simulated “outdoor” Urban (Grey), Countryside (Green) and Coastal (Blue) environments with a neutral indoor “Control” environment; (c) monitoring physiological and psychological outcomes before, during and after, exercise; and (d) examining whether physical activity in different simulated environments is associated with different time and physical effort perceptions.
Post-menopausal women are an important demographic for this research because compared to the usual samples of students they are: (a) older and possibly more sensitive to environmental contexts [
30]; (b) tend to engage in less physical activity [
31] and therefore may show more physiological heterogeneity in their responses to physical activity in different environments; and (c) because they tend to engage in less physical activity, they are a key target group for physical activity promotion interventions [
32]. Identifying the optimal environment for physical activity among this demographic could facilitate more targeted health promotion programmes. Finally, a previous study, using a similar cohort, found that affect (as measured by the Positive and Negative Affect Scale) improved more following a 60 min walk “outdoors” than on an indoor treadmill, demonstrating the importance of context for physical activity for this demographic [
33].
In addition to exploring the role of (simulated) natural environments on exercise outcomes by using a countryside (Green) setting, we also included a coastal (Blue) setting. Aquatic (blue) spaces are associated with a range of positive outcomes, over and above green spaces [
34,
35,
36]. Moreover, people who live near the coast are more likely to engage in physical exercise than those living inland [
3,
37,
38]. This may explain why coastal inhabitants have higher overall levels of self-reported health and well-being ([
7,
39], although see [
40]). Consequently, if the opportunity is available to undertake physical activity near water it may be particularly beneficial. By also examining the potential interactive effects of physical activity and Blue environments, we again extend investigations in this area. Including a simulated urban (Grey) environment in the study design enabled us to examine whether any video of an outdoors environment would be more beneficial than a neutral indoor Control setting.
Following Teas
et al. [
33], a repeated measures, cross-over experimental design was used, involving a sample of post-menopausal women. Following Pretty
et al. [
10], the role of natural environments during physical activity was investigated in a laboratory setting using projections of different environments (in this case videos) onto the wall in front of participants while they engaged in exercise on stationary equipment. An obvious disadvantage with simulated environments is reduced ecological validity [
41] although laboratory approaches are widely used in exercise research [
32]. Although Bowler
et al. [
12] only reviewed studies involving direct exposure to natural environments, they nonetheless acknowledged that controlled laboratory simulations are useful for reducing biases that may be present in field testing, and Kerr and colleagues [
42] found the difference in responses to physical activity between laboratory and outdoor conditions to be minimal (see also [
43]).
Stationary cycling was used as the form of physical activity in the study for several reasons. First, it was a lower impact form of exercise for our cohort of middle to older aged women, compared to say jogging. Second, in their study of green exercise
in situ, Mackay and Neill [
44] found that road and mountain biking were better at reducing anxiety compared to outdoor pursuits involving running or jogging. Although the authors offer no explanations for these results, it may be that the opportunity to free wheel and lower impact on joints may play a role. Finally, by using a stationary bike in a laboratory setting, rather than on roads outside, a much greater level of control could be applied to the study, for instance there were no traffic, gradient or weather issues (see also [
45]). This not only ensured that all participants experienced identical environmental stimuli, it was also much physically safer (something the ethics committee were concerned about with our cohort).
1.3. Hypotheses and Research Questions
Our hypotheses focused on comparing the outcomes of physical activity undertaken in the two simulated natural environment settings (“Green” and “Blue”) with the neutral “Control” environment to examine whether there were any additional benefits of exercising in these settings over simply the exercise per se. The simulated urban “Grey” environment was used as an additional control setting to see whether any distraction, even a busy urban one, during physical activity could have positive effects. The Control-Urban comparisons were thus more exploratory in nature.
Specifically, and building directly on Pretty
et al. [
10], we predicted that compared to physical activity in the neutral Control condition, activity in the simulated natural setting conditions (Green and Blue) would be associated with: (H1) more positive physiological outcomes (
i.e., greater pre-post drops in Mean Arterial Blood Pressure and Heart Rate) after exercise; (H2) better affective responses (
i.e., more positive valence and lower arousal) both during and after exercise; (H3) shorter perceptions of time and lower perceptions of effort during exercise; and (H4) more positive global evaluations (
i.e., greater enjoyment and willingness to repeat) post exercise. Further, also following Pretty
et al. [
10], we predicted that: (H5) the Urban (Grey) condition may result in worse physiological and psychological outcomes than the Control condition and thus support the contention that any benefits from watching natural scenes are not merely due to the distraction effects of viewing any simulated environment while engaging in stationary exercise, but are instead associated with the specific environments encountered.