There appears to be synergistic benefits in adopting physical exercises while exposed to nature. This is called ‘green exercise’. It has been found that green exercises improved
mood and self-esteem, as well as decreased anxiety and blood pressure. The mechanism of green exercise benefits is not clear. A study showed that the benefits might be due to the color green, because
it can make people calm. However, human perception is a whole, that is, the shape and color are synthetically together when people see a tree in the natural environments. Does the shape of tree
(object perception) also play a role on the benefits of green exercise? Therefore, this study attempts to explore the effect of color and object perception on green exercise benefits.
This study is a 2*2 between-subject experimental design. Independent variables are color (green versus gray) and object perception (with tree versus without tree). Dependent variables are blood
pressure, self-esteem, mood and cognition function. Seventy-six healthy participants were divided into four groups: Green-tree (color and object perception), Gray-tree (Object perception), Green (only
color perception) and Gray (control condition). Participants were required to do incremental cycling meanwhile watching a picture of green-tree, gray-tree, color green on the curtain, or watching a
blank curtain. All dependent variables were tested before and after cycling. According to World Health Organization training program, the incremental cycling test began at an intensity of 25 watt and
increased at 2 watt every two minutes, until reached level 12 (Fairly) of RPE (Rating of Perceived Exertion), and kept the intensity for 20 minutes. The whole test was about 30 minutes. Multivariate
analysis of variance (MANOVA) was performed to identify differences between groups, and main effect or/ simple effect analysis were performed when necessary.
The results showed : (a) There were no significant differences among groups in blood pressure (F3,72=1.290, p=0.285 for systolic blood pressure, F3,72=0.996, p=0.400 for diastolic blood pressure). (b)
There were main effects of object perception on tension (F1,72=4.334, p=0.041), vigor (F1,72=4.109, p=0.046), self-esteem (F1,72=6.426, p=0.013), total mood disturbance (TMD) (F1,72=5.651, p=0.020)
and choice RT (F1,72=5.538, p=0.021). Compared to no tree condition, the object perception (Green-tree and Gray-tree) groups were higher in vigor (p=0.044) and self-esteem (p=0.012), lower in tension
(p=0.041), TMD (p=0.021) and choice RT (p=0.020). (c) There were main effects of color perception on anger (F1, 72=4.897, p=0.030). Green (Green-tree and Green) groups have lower anger than gray
(Gray-tree and Gray) groups (p=0.033). (d) There was significant interaction between color and object perception on selective attention score (F1,72=5.288, p=0.024). Green-tree group was better in
selective attention score than Green group (F1,72=5.56, p=0.021).
The results indicated that the object perception of nature might be one of the potential reasons for green exercise benefits.