Lighting and acoustics matter for better work environments in ICUs

November 11, 2025

Workers in intensive care units were dissatisfied with the lack of natural light and high noise levels

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A 3 months study conducted in the intensive care unit (ICU) in Japan, revealed that healthcare workers experience reduced environmental satisfaction and concentration due to lack of natural light and excessive ambient noise. When designing ICUs, architects should focus on increasing natural light and mitigating noise. These factors could help enhance healthcare worker satisfaction, productivity, and quality of patient care.

Factors Affecting Healthcare Workers’ Perceptions of the Indoor Environment Quality (IEQ) in Intensive Care Units (ICUs)

Most people would agree that worker productivity is affected by the environmental characteristics of a workplace—noise, temperature, lighting, air quality, and more. This is especially true for healthcare workers in intensive care units (ICUs). ICUs are noisy due to life-support machines and healthcare workers moving rapidly to attend to patients, all of which create a stressful and fatiguing environment. Reducing workplace stress could improve healthcare workers’ productivity, reduce the likelihood of mistakes, and thus improve outcomes for patients.

Since April 2024, the Japanese Ministry of Health, Labor, and Welfare has been enforcing work-style reforms for physicians to improve the well-being of healthcare workers. While the reforms focus on capping work hours to prevent exhaustion due to overwork, improving the indoor environmental quality (IEQ) in ICUs is also an important aspect of limiting healthcare workers’ exhaustion. The Japanese Society of Intensive Care Medicine (JSICM) has created a set of guidelines to reduce patient discomfort in ICUs, which could indirectly reduce stress on healthcare workers as well. These guidelines specify a minimum recommended illuminance, an upper limit for ambient noise, and comfortable ranges for temperature and humidity. With regard to air quality in closed indoor spaces, the Ministry of Health, Labor, and Welfare recommends that adequate fresh air be supplied to keep CO₂ levels below 1,000 ppm, as a precaution against airborne SARS-CoV-2 transmission. Additionally, the World Health Organization recommends a maximum limit for particulate matter (PM_2.5).

A team of researchers from Institute of Science Tokyo (Science Tokyo), Japan, has studied the IEQ of a university hospital’s ICU in Tokyo, Japan, employing objective measurements and subjective assessments using questionnaires. This research project was led by Assistant Professor Wataru Umishio and Associate Professor Takuya Oki of the School of Environment and Society, Science Tokyo, together with Professor Kenji Wakabayashi, Associate Professor Nobuyuki Nosaka, Lecturer Ayako Noguchi, and Lecturer Yoshiki Sento of the Intensive Care Unit, Science Tokyo Hospital. Their findings were made available online on October 15, 2025, and will be published in Volume 92 of the journal Intensive and Critical Care Nursing on February 01, 2026.

“Field measurements were conducted across four IEQ domains—thermal, lighting, acoustic, and air quality—and paired with questionnaire responses from ICU healthcare professionals,” says Umishio, as he described the study, which ran between July and September 2023, adding, “The study explores associations between multi-domain IEQ and overall environmental satisfaction and perceived work productivity.”

Field measurements over 3 months showed that air quality metrics were within the recommended maxima for CO₂ and PM_2.5. While light illuminance exceeded the JSICM-recommended minimum, there was a significant degree of variation between areas that received adequate natural daylight and those with limited daylight access. Noise levels were entirely outside the JSICM guideline range, and temperatures in single-bed rooms were approximately 3 °C below the recommended values.

These observations aligned with responses to the survey questionnaire, with well over 60% of respondents saying they were at least slightly dissatisfied with the ICU’s overall IEQ. Umishio adds, “Satisfaction levels with thermal, lighting, and acoustic environments were significantly lower. Notably, for the acoustic environment, there were no positive responses, and approximately three-quarters of respondents expressed dissatisfaction.”

Respondents were particularly dissatisfied with the noise from medical equipment and the lack of natural light. Clearly, poor IEQ was impacting the productivity of healthcare workers in the university hospital’s ICU.

These findings provide directions for future ICU designs that improve healthcare worker satisfaction and productivity. As Umishio says, “Prioritizing daylight/circadian-supportive lighting and robust acoustic mitigation—implemented through coordinated efforts between architectural environmental engineering and critical care teams—offers a practical pathway to enhance staff experience and productivity while maintaining patient-centered care.”

Reference

Authors:: Wataru Umishio¹*, Nobuyuki Nosaka^2,3, Ayako Noguchi^2,4, Takuya Oki¹, Yoshiki Sento^2,5, and Kenji Wakabayashi^2,3
*Corresponding author
Title:: Multi-domain indoor environmental quality in intensive care units from a healthcare worker perspective: An observational study in Japan
Journal:: Intensive and Critical Care Nursing
DOI:: 10.1016/j.iccn.2025.104257
Affiliations:: ¹ Department of Architecture and Building Engineering, Institute of Science Tokyo, Japan
² Intensive Care Unit, Institute of Science Tokyo Hospital, Japan
³ Department of Intensive Care Medicine, Institute of Science Tokyo, Japan
⁴ Department of Disaster and Critical Care Nursing, Track of Nursing Innovation Science, Institute of Science Tokyo, Japan
⁵ Department of Anesthesiology, Institute of Science Tokyo, Japan