Saliva and facial expressions highlight stress levels, Japanese aerospace and Shiseido research finds

Using a closed-off chamber environment (isolation chamber) simulating the International Space Station (ISS), Shiseido and National Research and Development Agency JAXA have conducted their latest research project.

What is being analysed?​

To analyse how the circadian rhythm of stress hormone is disrupted when placed under stress, along with the distortion in facial expressions, the duo used the training facility in JAXA's Tsukuba Space Centre.

Together, they specifically monitored a “disruption in the circadian rhythm of salivary stress hormone (cortisol)”​ along with an “increased distortion in facial expression during the stay in the isolation chamber”,​ Shiseido revealed in a recent press release.

The research team’s efforts and consequential results indicate the potential to conduct efficient stress self-assessment through observing and identifying changes in saliva and facial expressions.

Test inspiration​

Following these outcomes, this ongoing research will now see Shiseido concentrate on evolving its beauty products and services to limit the effects of stress on both the skin and body. JAXA will focus on developing a stress-assessment technique for astronauts in the ISS.

Without the access to regular professional physical assessments on both their mental and physical health, JAXA has focused on the possibility of creating biomarkers for stress self-assessments to enable astronauts to monitor their stress levels themselves.  

This recent research saw JAXA control the experiment conditions and watch participant's reactions and behaviours while in the isolation chamber.

While in the test environment, eight participants remained in the isolation chamber for two weeks. Baseline data was collected before entering and once exiting the chamber.

The science behind the results​

1. Salivary cortisol​

Optimally performing cortisol follows an already-identified pattern called the “cortisol curve”​. A healthy curve displays cortisol levels as high in the morning and then reduces throughout the day and evening.

During this test, the duo measured the salivary cortisol level four times a day (in the morning, at noon, in the afternoon and at night). The results of the three latter tests showed a distortion in the circadian rhythm of cortisol at the beginning of their time in the isolation chamber and one day before the end of their stay, showing that their stress levels rose. These stress levels returned to normal after leaving the isolation chamber.

2. Facial distortion​

Shiseido analysed facial distortion levels after looking at the symmetry of facial expressions. The findings revealed that facial distortion was developed during the time the participants spent in isolation.

Next steps​

On 2nd March 2018, Dr Junichi Hosoi, Shiseido’s researcher, who has been dedicated to research on the relationship between stress and skin/immune system, will demonstrate the results of this research at I-ISEF (ISEF for Industries), part of the 2nd International Space Exploration Forum (ISEF) programme.

Sponsoring the International Space Exploration Forum (ISEF) event, which aims to highlight international collaboration in space exploration, Shiseido will also showcase the joint research presented at the 63rd Annual Meeting of Japan Society of Aerospace and Environmental Medicine, along with making product introductions and sampling Shiseido's Ultimune Power Infusing Concentrate.

Shiseido will now also highlight the applicability of these test results by adding a stress indicator to existing solutions. Its Smile app, for example, which takes images of the user before quantifying, evaluating the expression and recording the data, will also soon incorporate a stress measuring function.