Evidence Informing
the Sapien Principles
RESEARCH & REFERENCES
Sapien Spaces draws from research across environmental health, building science, neuroscience, environmental psychology and human performance, together with established standards and technical guidance.
The references below provide a selected evidence base for the ten Sapien Principles. They are intended to show the research informing our approach rather than represent an exhaustive literature review. Evidence continues to evolve and is interpreted within the specific context of each project.
Browse by Principle
How we use research
No single study, metric or standard determines a Sapien Spaces recommendation. Research is considered alongside the architecture, climate, location, occupants, building systems, operational requirements, budget and objectives of each project.
Evidence is therefore used as a decision-making resource rather than as a universal prescription. Where research is emerging, mixed or context-dependent, this is treated accordingly.
01 Breath
Air quality · ventilation · filtration · moisture
Breath considers the quality of the air people continuously experience indoors. Relevant factors include ventilation, filtration, outdoor-air infiltration, pollutant sources, combustion, moisture, air cleaning and monitoring.
Research supports treating indoor air quality as a system rather than a single measurement. Ventilation and source control can influence pollutant concentrations, while filtration, moisture management and building operation affect how indoor conditions change over time.
SOURCES & REFERENCES
ANSI/ASHRAE Standards 62.1-2025 & 62.2-2025 — Ventilation and Acceptable Indoor Air Quality
Industry standards addressing ventilation, filtration, source control and acceptable indoor air quality.
ASHRAE Standards 62.1 & 62.2
Meta-Analysis of the Effect of Ventilation on Intellectual Productivity (2023)
Meta-analysis examining ventilation rates and measures of task performance.
View study on PubMed
Du et al. (2020). Indoor CO₂ Concentrations and Cognitive Function: A Critical Review. Indoor Air.
DOI: 10.1111/ina.12706
Reviews experimental research on indoor CO₂, ventilation and cognitive outcomes.
View study on PubMed
U.S. Environmental Protection Agency — Indoor Air Quality
Practical information on indoor pollutants, ventilation, combustion and VOCs.
EPA: Care for Your Air
02 Rhythm
Daylight · circadian light · darkness
Rhythm considers how light changes across the day and how architecture influences the light-dark patterns experienced by occupants.
Light supports vision, but it also provides biological timing information. Research examines the timing, intensity, spectrum and duration of ocular light exposure in relation to circadian regulation, alertness and sleep. Daylight access, electric lighting, glare, evening light and darkness at night are therefore considered together rather than independently.
SOURCES & REFERENCES
CIE (2024). Recommending Proper Light at the Proper Time — 3rd Edition.
Current position statement from the International Commission on Illumination regarding biologically relevant light exposure and melanopic EDI.
Read the CIE Position Statement
Lewis et al. (2024). Architecture, Light, and Circadian Biology: A Scoping Review. Science of the Total Environment.
DOI: 10.1016/j.scitotenv.2024.177212
Reviews evidence connecting architectural features, light-dark exposure and circadian biology, while identifying significant research gaps.
View study on PubMed
Brown et al. (2022). Recommendations for Daytime, Evening, and Nighttime Indoor Light Exposure. PLOS Biology.
DOI: 10.1371/journal.pbio.3001571
International expert consensus on light exposure in relation to physiology, sleep and wakefulness.
View study on PubMed
03 Nourishment
Water quality · hydration · food environments
Nourishment considers the built environment around drinking water, hydration and, where relevant, food.
Safe water requires appropriate source management, treatment, distribution, maintenance and monitoring. The design and organization of food and beverage environments can also influence what people see, access and choose. Sapien Spaces therefore considers both environmental quality and the practical conditions that support everyday routines.
SOURCES & REFERENCES
World Health Organization (2026). Guidelines for Drinking-water Quality: Fourth Edition incorporating the first, second and third addenda.
Current WHO reference for health-based drinking-water quality and risk management.
WHO Drinking-water Quality Guidelines
Lindstrom, Tucker & McVay (2023). Nudges and Choice Architecture to Promote Healthy Food Purchases in Adults.
DOI: 10.1037/adb0000892
Review of environmental and choice-architecture interventions affecting food purchasing behaviour.
View study on PubMed
Does Hydration Status Influence Executive Function? A Systematic Review (2021).
Reviews evidence relating hydration status to executive-function outcomes and illustrates that hydration research is not uniform across studies.
View study on PubMed
04 Sensory Comfort
Acoustics · thermal conditions · humidity · sensory load
Human comfort is multisensory. Temperature, radiant conditions, humidity, air movement, acoustics, reverberation, glare and other sensory inputs can interact rather than being experienced independently.
Sensory Comfort considers these conditions in relation to occupant preference, activity and context. The objective is not to prescribe one universally “correct” environment, but to understand the range of conditions that can support comfort, function and appropriate levels of stimulation.
SOURCES & REFERENCES
ANSI/ASHRAE Standard 55-2023 — Thermal Environmental Conditions for Human Occupancy
Technical standard for assessing satisfactory thermal environments.
ASHRAE Standard 55
World Health Organization (2018). Environmental Noise Guidelines for the European Region.
Evidence-based health guidance relating to environmental noise exposure.
WHO Environmental Noise Guidelines
Arsad et al. (2023). Assessment of Indoor Thermal Comfort Temperature and Related Behavioural Adaptations: A Systematic Review.
DOI: 10.1007/s11356-023-27089-9
Shows substantial variation in thermal-comfort conditions according to climate, building type, ventilation and population.
View study on PubMed
Torresin et al. (2018). Combined Effects of Environmental Factors on Human Perception and Objective Performance. Indoor Air.
DOI: 10.1111/ina.12457
Reviews interactions among acoustic, thermal, visual and air-quality conditions.
View study on PubMed
05 Movement
Circulation · ergonomics · mobility · active design
Movement considers how planning, circulation, accessibility and everyday spatial choices can make physical activity easier—or create barriers to it.
The research base spans scales from buildings to neighbourhoods. Within projects, Sapien Spaces considers circulation, stairs, ergonomics, accessibility, destinations and opportunities for incidental movement while maintaining ease, dignity and functionality.
SOURCES & REFERENCES
Pontin et al. (2022). Objectively Measuring the Association Between the Built Environment and Physical Activity: A Systematic Review.
DOI: 10.1186/s12966-022-01352-7
Systematic review of objectively measured built-environment characteristics and adult physical activity.
View study on PubMed
Zhang et al. (2022). The Impact of Interventions in the Built Environment on Physical Activity Levels: A Systematic Umbrella Review.
DOI: 10.1186/s12966-022-01399-6
Synthesizes review-level evidence on built-environment interventions and activity.
View study on PubMed
Prince et al. (2026). Impacts of Built Environment Changes on Physical Activity in Canada: A Systematic Review of Natural Experiments.
Recent Canadian evidence on physical-environment changes and physical activity.
View study on PubMed
06 Materiality
Materials · emissions · durability · transparency
Materials influence a space through more than appearance. They can affect indoor air through chemical emissions, determine maintenance and cleaning requirements, influence durability and provide tactile and sensory information.
Sapien Spaces considers material health alongside architectural intent and performance. Terms such as “natural,” “sustainable” or “low VOC” are not treated as complete evidence on their own; product composition, emissions, intended use and available documentation are considered in context.
SOURCES & REFERENCES
U.S. Environmental Protection Agency — Volatile Organic Compounds’ Impact on Indoor Air Quality.
Current EPA overview of VOC sources, indoor concentrations and exposure considerations.
EPA VOC and Indoor Air Quality Guidance
Liu et al. (2022). Health Effects of Exposure to Indoor Volatile Organic Compounds from 1980 to 2017: A Systematic Review and Meta-analysis. Indoor Air.
DOI: 10.1111/ina.13038
Systematic review and meta-analysis of health evidence associated with indoor VOC exposure.
View study on PubMed
U.S. EPA Indoor AirPlus (2024). How to Find Compliant Building Materials.
Practical guidance concerning lower-emission paints, finishes, flooring, adhesives, insulation and other building materials.
EPA Indoor AirPlus Building Materials Guide
07 Nature
Views · landscape · daylight · outdoor connection
Nature considers meaningful contact with natural environments rather than simply adding decorative planting.
Research has investigated relationships between nature exposure and stress, attention, affect and restoration. Within the built environment, relevant conditions can include views, landscape, access to outdoor space, daylight, natural patterns and the relationship between architecture and its surrounding environment.
SOURCES & REFERENCES
Shuda, Bougoulias & Kass (2020). Effect of Nature Exposure on Perceived and Physiologic Stress: A Systematic Review.
DOI: 10.1016/j.ctim.2020.102514
Reviews physiological and self-reported stress responses associated with nature exposure.
View study on PubMed
Stevenson, Schilhab & Bentsen (2018). Attention Restoration Theory II: A Systematic Review.
DOI: 10.1080/10937404.2018.1505571
Meta-analytic review examining cognitive processes potentially affected by exposure to natural environments.
View study on PubMed
Rhee et al. (2023). Effects of Nature on Restorative and Cognitive Benefits in Indoor Environment. Scientific Reports.
Experimental research specifically examining nature exposure within indoor and semi-indoor settings.
View study on PubMed
08 Restoration
Sleep · privacy · calm · recovery
Restoration considers environmental conditions that allow people to withdraw from stimulation, rest and recover.
Sleep and restorative experience can be influenced by multiple environmental inputs, including light, temperature, noise, ventilation and privacy. Sapien Spaces therefore considers bedrooms and restorative spaces as integrated environments rather than treating any one factor as a complete solution.
SOURCES & REFERENCES
Kretzschmar et al. (2026). The Effect of Exposure to Artificial Light at Night on Sleep Disturbance: A Systematic Review and Meta-analysis. Environmental Research.
DOI: 10.1016/j.envres.2026.123689
Large systematic review and meta-analysis examining nighttime light exposure and sleep disturbance.
View study on PubMed
Troynikov, Watson & Nawaz (2018). Sleep Environments and Sleep Physiology: A Review. Journal of Thermal Biology.
DOI: 10.1016/j.jtherbio.2018.09.012
Reviews environmental and thermal conditions relevant to sleep.
View study on PubMed
Macedo, Ornstein & Elali (2022). Privacy and Housing: Research Perspectives Based on a Systematic Literature Review.
DOI: 10.1007/s10901-022-09939-z
Reviews privacy as a psychological, social and spatial aspect of residential environments.
View study on PubMed
09 Technology
Controls · automation · monitoring · digital environments
Technology considers how building systems can respond to occupants without creating unnecessary complexity.
Sapien Spaces evaluates controls, automation, monitoring and digital systems in relation to usability, personal agency, environmental performance and privacy. Technology is treated as a supporting layer of the built environment—not as an objective in itself.
SOURCES & REFERENCES
Lechner et al. (2021). Does Thermal Control Improve Visual Satisfaction? Interactions Between Occupants’ Self-perceived Control, Visual, Thermal and Overall Satisfaction. Indoor Air.
DOI: 10.1111/ina.12851
Research showing the importance of perceived occupant control in environmental satisfaction.
View study on PubMed
From Occupants to Occupants: A Review of Occupant Information for HVAC Occupant-centric Control (2021).
Review of occupant-centric HVAC systems and the use of real-time occupant information to improve environmental responsiveness.
View study on PubMed
Indoor Air Quality Monitoring Systems Based on Internet of Things: A Systematic Review (2020).
Reviews connected sensing and monitoring systems used to identify indoor-air-quality conditions.
View study on PubMed
10 Connection
Belonging · interaction · accessibility · adaptability
Connection considers how environments support participation, belonging, accessibility, interaction and choice.
Design can create opportunities for social contact while also respecting privacy and individual preference. Accessibility and adaptability are equally important: environments should accommodate different bodies, abilities, routines and stages of life wherever practicable.
SOURCES & REFERENCES
Bower et al. (2023). The Impact of the Built Environment on Loneliness: A Systematic Review and Narrative Synthesis. Health & Place.
DOI: 10.1016/j.healthplace.2022.102962
Synthesizes research on housing, neighbourhood design, greenspace and loneliness.
View study on PubMed
Watchorn et al. (2019). An Integrated Literature Review of the Current Discourse Around Universal Design in the Built Environment.
Review of universal design, inclusion and social participation within built environments.
View study on PubMed
A Scoping Review of Public Building Accessibility (2021).
Reviews research on accessibility, environmental features and participation in public buildings.
View study on PubMed
Core standards & guidance referenced
In addition to peer-reviewed research, Sapien Spaces consults recognized technical standards, public-health guidance and established built-environment frameworks where relevant to the project.
International WELL Building Institute — WELL v2
Air, Water, Nourishment, Light, Movement, Thermal Comfort, Sound, Materials, Mind and Community.
WELL v2 Overview
ASHRAE — Standards 62.1 & 62.2
Ventilation and acceptable indoor air quality.
ASHRAE 62.1 & 62.2
ASHRAE — Standard 55
Thermal environmental conditions for human occupancy.
ASHRAE Standard 55
World Health Organization — Drinking-water Quality
Health-based water-quality guidance.
WHO Drinking-water Guidelines
World Health Organization — Environmental Noise Guidelines
Public-health guidance concerning environmental-noise exposure.
WHO Environmental Noise Guidelines
International Commission on Illumination — CIE
Scientific and technical guidance concerning light and integrative lighting.
CIE Proper Light at the Proper Time
U.S. Environmental Protection Agency — Indoor Air Quality
Public guidance relating to indoor pollutants, VOCs and lower-emission materials.
EPA Indoor Air Quality Resources
Research evolves
Research concerning human health, behaviour and the built environment continues to evolve. Findings may vary according to population, exposure, methodology, building type and environmental context. Associations reported in research do not necessarily establish causation, and individual responses may differ.
Sapien Spaces uses research and technical guidance as inputs within a broader project-specific advisory process. The information presented on this website is for general educational purposes and does not constitute medical, architectural, engineering or other regulated professional advice.
From research
to project decisions.
Sapien Spaces translates relevant research into project-specific considerations for private residences, major renovations, multi-family developments, hospitality, commercial and institutional environments.
Monica Dabrowski has completed training in the WELL Building Standard. Sapien Spaces is an independent consultancy and is not affiliated with, endorsed by or certified by the International WELL Building Institute. WELL™, the WELL Building Standard™ and related marks are trademarks of the International WELL Building Institute pbc. Completion of WELL-related training does not constitute the WELL AP credential.