Can architecture really heal, and can we measure the health outcomes of design strategies? Architects all have the intention of making the environments they design capable of aiding healing, but this may not always be the case. With construction costs rising and patients becoming increasingly demanding about quality of care, hospital administrators are understandably wary of unproven assumptions about the effects of light, colour and design on patient health.

In the US, there is a relatively new but growing movement towards “evidence-based design practice”, in which goals are established at the outset and research is conducted to illuminate the link between design and its impact on owners and user groups. With research data, hospitals could be commissioned using quantifiable goals – for example, length of stay, medical errors and amount of medication – and specific design strategies demonstrated to relate to whatever those goals might be.

The challenge is that, despite many years of environmental design research, many important elements remain relatively overlooked. Lighting and colour are of particular importance, as both are considered to have an effect on healing. There is a long-standing belief that light has healing qualities, to the point where some forms of traditional medicine have incorporated sunlight within certain therapies. The question is, do we really know how to use light and colour in design achieve specific health outcomes?


In June of 2005, the College of Fellows of the American Institute of Architects acknowledged the importance of an evidence-based approach to hospital design by awarding the biannual Latrobe Fellowship to a tripartite team consisting of a practicing architectural firm (Chong Partners Architecture), a healthcare system (Kaiser Permanente) and a university research community (University of California, Berkeley). This team is researching the impacts of lighting and colour on health outcomes to provide solid data that hospital architects and administrators could potentially use to make well-informed decisions about the design of their patient environments.

The most compelling part of this research is set to be completed in mid-2007. It comprises two major primary research efforts, one of which is a very large database study linking room design attributes, patient surveys and patient medical records across 30 hospitals. Its significance is the size of the database, which will add credibility to the results. The second is a laboratory experiment exploring cognitive and physiological responses to lighting, notable by linking specific lighting attributes to physiological measures known to indicate health outcomes.

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“There is a long-standing belief that light has healing qualities.”

Several literature reviews and meta-analyses that include lighting and colour research have recently been published. Collectively, these reveal some fascinating connections between light and health. A wealth of additional empirical data from biomedical research further illuminates behavioural and physiological responses to electrical lighting, daylight and solar orientation.

What do we know about lighting and health with enough certainty and specificity that a hospital administrator could actually apply the knowledge to decisions about facilities? Ideally, designers would want guidelines on intensity, spectrum, timing and controls. Unfortunately, the research does not yet provide sufficient evidence for that level of definitive guidance.

Schweitzer et al¹ conclude that most of the relevant research has been concentrated on a limited number of settings and is not a sufficient basis for design guidelines for the physical elements of an optimal healing environment. Nevertheless, there is a great deal of related research that, while not directly applicable, does provide strong indications of which qualities are important, why and to what effect.


In 2002, David Berson et al identified photoreceptor cells in the retina connected to the suprachiasmatic nucleus of the hypothalamus and the pineal gland. Light reaching these cells affects the body’s circadian cycles, including the production of the hormones that regulate sleep (melatonin) and alertness (cortisol).

Circadian cycles influence health and human performance in numerous ways, including sensitivity to drugs, hormone secretion, sleeping, feeding, growth, reproductive systems and immune responses². Hospital environments provide varying degrees of exposure to natural daylight and often use electrical lighting systems that are visually functional but biologically not sensitive to circadian cycles. The levels of lighting needed for vision may be much lower than those required for biological stimulation.

Brightness, spectrum, timing and duration seem to affect circadian rhythms. Rhythms are stronger in a bright-day environment than in a dim-day environment. Blue light may be the most productive for the circadian system. Some research (Beauchemin KM & Hays P, 1996) strongly suggests that bright light in the morning is more effective for reducing depression than bright light in the evening.

Many studies show that stress responses change rhythmically with diurnal and electrical lighting modulation. Specific patient populations respond to light therapeutically. Bright light reduces depression in patients with bipolar disorder and seasonal affective disorder (SAD.) This is especially true if the light exposure is in the morning.

Research results such as these show that lighting is more than just illumination. Biological processes that affect health can be kickstarted by different types of lighting and it can be therapeutic in some circumstances, notably ageing and depressed patient populations.


Hospital administrators might want to understand the economic implications of design choices. Sunny rooms have been shown to lower the length of stay of depressed patients. In 1998, Beauchemin & Hays found that female patients in a cardiac ICU had a shorter length of stay in sunny rooms.

A 2005 study by Walch JM et al showed that patients residing in a brighter area of the hospital were exposed to 46% higher intensity sunlight on average and took 22% less analgesic medicine than their counterparts with the same medical condition on the darker side of the hospital. This equated to a 21% cost differential.

There is a need for more lighting research, like that being done for the Latrobe Fellowship, which directly links lighting attributes in design settings to measurable health outcomes. In the interim, however, we have strong indications that lighting is important in terms of affecting mood and the circadian system, and therefore well-being.


Research suggests that it is very important to provide direct access to natural daylight. When electrical light is used instead, it might be preferable for it to simulate a natural light spectrum cycle. Research might also support the concept of inboard toilet rooms with a maximum window perimeter, as well as single occupancy rooms that allow greater access to available daylight for all patients. Solar orientation is important as a means of extending duration of daylight penetration, especially in winter. The ability to vary light intensity may be significant, with bright light in the morning and lower intensity restful light at night.

Lighting design needs to balance consideration of these biological needs with colour rendition of the patient’s skin and adequate lighting for the medical staff, to minimise medical errors. Lighting controls may provide the variation needed for this range of requirements.

“Sunny rooms have been shown to lower the length of stay of depressed patients.”


We know less about colour. In a 2004 study, Tofle et al3 reviewed 3,000 citations on colour to identify supportable design implications for the use of colour in healthcare design. They concluded that the literature is insufficient to support causal relationships between colour and health outcomes. They also claimed that colour’s influence on emotional states and behavioural activities is unsubstantiated by proven results.

There are, however, demonstrable impressions of colour that can affect the experience and performance of people in particular environments. A sense of spaciousness, for example, can be evoked by colour, although brightness is a more important factor than hue.

For hospital design, perhaps the most important finding is that associations between colour and mood exist; these are not a one-to- one relationship between colour and emotion, but culturally learned associations, as well as effects of peoples’ physiological and psychological make up. As we strive to accommodate more cultural diversity within our hospitals, the ability to cost-effectively adapt colour to suit cultural preferences and avoid cultural taboos will become increasingly important.

The process of research is one in which knowledge is created, which in turn serves as a basis for further research. Design demands application of the best available information at the time. Current research provides some indicators about lighting and colour design that demand attention. The answers are not as clear-cut as some may claim but there is enough evidence to suggest that lighting in a hospital environment really matters.

1. Schweitzer M, Arch M, Gilpin L MFA RN, and Frampton, S PhD, ‘Healing
Spaces: Elements of Environmental Design That make an Impact on
Health’.Journal of Alternative and Complementary Medicine, Vol. 10,
Supplement 1, 2004, ppS71–83.
2. Eve Edelstein PhD. ‘Translational design: The Relevance of Neuroscience
to Architecture’. ASHE Proceedings. 2006.
3. Tofle RB, Schwartz B, Yoon S-Y, Max-Royale A. ‘Color in Healthcare
Environments: A Critical review of the Literature’. Coalition for Health
Environments Research (CHER). 2004.

Research contributed by the 2005 Latrobe Fellowship team
– Gordon Chong, FAIA; Eve Edelstein, PhD, Barbara Denton,
Assoc AIA; Robert Mangel, PhD; Galen Cranz, PhD; W.Mike
Martin, FAIA, PhD.