Synergistic effects of edible plants with light environment on the emotion and sleep of humans in long-duration isolated environment

The emotion and sleep-related problems of humans who are on mission of deep-space and deep-sea exploration are topics of special interest because of the isolated environment. Effective regulatory approaches should be developed to manage the positive emotions and sleep quality in a long-duration isolated environment. The results reported that emotion and sleep were closely linked to each other because plants could significantly regulate humans’ emotion and sleep through their own color and fragrance. Additionally, the light conditions prevailing in that location also had significant influence on humans’ emotion and sleep. There have been few reports on the synergistic effects of plants with light environment on humans’ physical and mental health. In this research, three species of edible plants and three color temperature levels that were commonly used in people's living environment were selected. Then orthogonal tests were conducted in the cabins of “Lunar Palace I” in the middle of the third phase of the “Lunar Palace 365″ experiment, and salivary cortisol levels, emotion, and sleep conditions of the volunteers were measured. The results showed that in the long-duration isolated environment, strawberry had a better effect than purple rape and coriander on improving positive emotion. Exposure to coriander before bedtime might help people to rapidly go to sleep, increase sleep integrity, and sleep efficiency in the isolated environment. Moreover, there appeared to be a positive synergistic effect of edible plants with light environment on micro-awakening index and sleep efficiency. These results provided a scientific basis for improving the physiological and psychological health of people in the long-duration isolated environment by changing the light environment with appropriate plants.