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

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

It is a popular belief that colours impact one's psychological and affective functioning. However, clear-cut scientific evidence is still lacking, largely due to methodological challenges. Virtual reality (VR) enabled us to control and modify the environment. We exposed 60 participants to red or blue environments varying in lightness and saturation. We assessed participants' physiological responses (i.e. arousal) with heart rate and skin conductance measures, and their self-reported levels of valence and arousal in response to the coloured environments. The results revealed physiological effects of lightness and hue. When compared with the baseline measures, heart rate increased, and heart rate variability decreased more in the dark than the medium lightness rooms. Both measures signalled higher arousal in the darker room, irrespective of hue. Also, when compared with the baseline measures, skin conductance increased more in the red than the blue rooms, again signalling higher arousal in the red condition. The difference between the red and the blue conditions was detectable only on some saturation and lightness combinations. We conclude that being immersed in environments of different colours can change physiological arousal. However, not all changes are driven by hue and not all the effects are measurable on all physiological parameters.

Thirty years of telemetry-based data acquisition for cardiovascular drug safety evaluation: Applications and optimization

Conducting safety evaluations of new drugs using conscious animals has been a specialty of our working group for thirty years. In this article, we review the various technical challenges and solutions dealt with over the years to improve both the data quality and the well being of our animal subjects. Of particular interest for us has been the use of telemetry-based data acquisition for conducting studies on cardiovascular (CV) function. This includes the evolving technical aspects of the studies, as well as the development of new applications that take advantage of this technical approach.

The impact of environmental and biological factors on the resting heart rate of dogs as assessed using 20 years of data from safety pharmacology studies

INTRODUCTION

A safety pharmacology study detects and evaluates potential side effects of a new drug on physiological function at therapeutic levels and above and, in most cases, prior to the initiation of clinical trials. The aim of this study was to investigate the effects of environmental and biological factors on resting heart rate (HR), a representative cardiac parameter in cardiovascular safety pharmacology.

METHODS

Over twenty years, 143 dogs (Beagles, Labradors and mongrels) received implanted telemetry transmitters to measure aortic pressure (AP), left ventricular pressure (LVP), Electrocardiogram (ECG) and body temperature. Throughout the 7-h period of data collection, data were continuously recorded without drug treatment and included the range of HRs resulting from spontaneous physiological changes. Statistics and visualizations were calculated using R and Spotfire.

RESULTS

Beagles had a higher HR than the mongrels, while Labradors had a lower HR than mongrels. Labradors were found to have a sex-based difference in HR, with females having a higher HR. A higher HR was observed in young animals of all breeds when they were in contact with humans. The cage system affected the HR of Labradors and mongrels more than Beagles. Larger dogs (e.g. Labrador) have a lower HR than smaller dogs (Beagles). Animals that are younger were found to have more HR variability and have a higher HR than older animals. In addition, older animals reacted less to the application period and human interaction than younger animals. The HR response of animals inside a cage system may depend on the cage system in which they were bred. A familiar cage system typically has less impact on HR.

DISCUSSION

This retrospective data base evaluation has demonstrated the impact of environmental and biological factors on cardiovascular parameters in the context of performing safety pharmacology studies. Breed, sex, age and the type of cage system used affected, at least in some cases, the HR and its variability. They should therefore be carefully considered when designing safety pharmacology studies to have the highest possible test sensitivity.

Effects of Changes in Environmental Color Chroma on Heart Rate Variability and Stress by Gender

With increasing time spent indoors during the coronavirus disease pandemic, occupants are increasingly affected by indoor space environmental factors. Environmental color stimulates human vision and affects stress levels. This study investigated how changing environmental color chroma affected heart rate variability (HRV) and stress. The HRV of nine males and fifteen females was measured during exposure to 12 color stimuli with changes in chroma under green/blue hues and high/low-value conditions, and a stress assessment was performed. The effect of chroma on the HRV of males and females was verified, but the interaction effect between chroma and gender was not. ln(LF) and RMSSD were valid parameters. ln(LF) of males and females decreased as chroma increased under the green hue and low-value conditions; RMSSD was reduced as chroma increased in the blue hue and low-value conditions. ln(LF) decreased as chroma increased under blue hue and high-value conditions in males. Color–stress evaluation revealed that the higher chroma under high-value conditions, the more positive the stress emotion, and the lower the chroma under low-value conditions, the more negative the stress emotion. As chroma increased under low-value conditions, color is a stress factor; for men, this effect was more evident in the blue hue.