Effects on Heart Rate Variability of Stress Level Responses to the Properties of Indoor Environmental Colors: A Preliminary Study

Abstract

Color is the most potent stimulating factor affecting human vision, and the environmental color of an indoor space is a spatial component that affects the environmental stress level. As one of the methods of assessing the physiological response of the autonomic nervous system that influences stress, heart rate variability (HRV) has been utilized as a tool for measuring the user’s stress response in color environments. This study aims to identify the effects of the changes of hue, brightness, and saturation in environmental colors on the HRV of two groups with different stress levels—the stress potential group (n = 15) and the healthy group (n = 12)—based on their stress level indicated by the Psychosocial Well-being Index (PWI). The ln(LF), ln(HF), and RMSSD values collected during the subjects’ exposure to 12 environments colors of red and yellow with adjusted saturation and brightness, were statistically analyzed using t-test and two-way ANOVA. The results show that the HRV values in the two groups did not significantly vary in response to the changes in hue, brightness and saturation. The two groups’ stress factors distinguished according to the stress levels by the PWI scale affected the In(LF) parameter, which demonstrates that the PWI index can be utilized as a reliable scale for measuring stress levels. The ultra-short HRV measurement record and the use of a sole In(LF) parameter for stress assessment are regarded as the limitations of this study.

Effects of environmental colours in virtual reality: Physiological arousal affected by lightness and hue

“…Once seated, they were instructed to slowly move their head and freely explore the room for 3 min. This duration is in line with recent studies in the field ( [41,[43][44][45][46][47][48]; table 1). Subsequently, they received instructions on the sustained attention task [67], which they performed for another 3 min, to ensure they were focused at all times.…”

“…Overall, running such well-controlled studies is demanding and it requires high investment in terms of money and time. These numerous methodological challenges probably explain why we found few wellcontrolled empirical studies that could inform us on affective changes in response to colour [7,9,[30][31][32][33]35,[37][38][39][40][41][42][43][44][45][46][47][48]. Among these, even fewer studies used physiological measurements and experimentally manipulated and analysed lightness and/or saturation in addition to hue ([7,41,42]; table 1).…”

“… 2020 red, green, blue + white not controlled NCS simulated rooms in VR ECG 2 min for each colour condition 5 min prior to and in between the testing sessions within-subjects (order counterbalanced) 55 pps (7 women) M = 21.3 Hong Kong, China no effect of hue on ECG [ 44 ] Llinares et al . 2021 four warm and four cold hues For each hue, two levels of chroma; matched in lightness MCS simulated rooms in VR ECG 1.5 min for each colour condition 3 min prior to the testing session between-subjects; each participant saw three rooms 160 pps (67 women); at least 20 pps per colour condition M = 23.6 Spain main effect of cold/warm colours on ECG (cold > warm) [ 45 ] Oh et al . 2021 red, yellow for each hue, two levels of brightness and three levels of chroma MCS laboratory testing spaces (cubicles), colours manipulated by paint ECG 2.5 min for each colour condition prior to the testing session (unreported duration) within-subjects (fixed order) 27 pps (13 women) M = 22.0 Korea no effect of colour on ECG [ 46 ] Bower et al .…”

“…Finally, it is also not an easy task to experimentally immerse participants in coloured spaces, and this can be achieved either by changing colours in physical rooms [ 7 , 30 – 32 , 35 , 37 , 40 , 41 , 45 , 48 ] or by simulating coloured environments in virtual reality (VR; [ 32 , 33 , 43 , 44 , 46 , 47 ]). When it comes to physical spaces, one must be able to change interior colours of the same room in a consistent, reproducible and timely manner.…”

Gender differences between the emotions experienced and those identified in an urban space, based on heart rate variability

“…It has been suggested that the sympathetic activation and parasympathetic withdrawal of autonomic nervous functioning during acute stress can be evaluated using HRV parameters (Spellenberg et al, 2020). However, contradictory and inconsistent results have been reported in the relationship between HRV parameters and stress (Oh et al, 2021). It is not, therefore, possible to assert that certain specific HRV parameters represent stress, although some recent studies have pointed to HRV parameters being highly correlated with stress (Kim et al, 2018).…”