You Can Solve a Lot of Problems With a Good Night’s Sleep

The State of Arizona, 50% of which is desert, presents unique challenges for unhoused populations that extend far beyond what is understood in more temperate climates. Phoenix’s extreme heat season now spans nearly half the year [7], with heat-related deaths among unhoused individuals reaching record levels. In 2023 and 2024, Maricopa County reported over 600 heat-associated deaths in each year [8]. In 2024, 49% (n=298 ) of these individuals were experiencing homelessness at the time of death [9].

Heat does not just threaten survival—it systematically undermines sleep [10], [11]. The human body’s thermoregulatory mechanisms operate within a “narrow functional range of 35∘C to 41∘C ” [12], with a drop in core temperature required to initiate and maintain sleep [13]. This is almost impossible when ambient temperatures remain above 90∘F throughout the night, which, as illustrated by Figure 1, is a common occurrence through the Phoenix summer.

Figure 1.Average temperatures in Phoenix, Arizona, by month. National Oceanic and Atmospheric Administration. (2020). United States climate normals 2020: Phoenix, AZ [Dataset]. NOAA National Centers for Environmental Information. https://www.ncei.noaa.gov/ products/land-based-station/us-climatenormals; data visualization Claude (Anthropic) (2024). Phoenix, Arizona, average temperatures by month [data visualization]. https://claude.ai

For unhoused individuals in Phoenix, even finding shade during daytime hours for rest becomes a matter of survival rather than comfort. Phoenix’s landscape is dominated by concrete and asphalt, making it one of the largest urban heat islands in the country. Figure 2 shows an image of Downtown Phoenix. During the summer, sidewalks and roads can register temperatures up to 175∘F [14]. While the City of Phoenix operates a robust system of cooling centers, these indoor spaces do not allow sleeping. For those who secure overnight shelter beds, relief is often partial at best, as many congregate shelters in Maricopa County lack adequate cooling capacity. Individuals are then left with the choice to sleep outside in the heat or inside in a crowded setting, neither of which provides for a good night’s sleep.

Figure 2.Downtown Phoenix features a light rail system and moderate urban development with little green space. (Photo credit: Dan Terrell of Terrell Photography (Terrellphotography.art; e-mail: photos@terrellphotography.art).)

While temperature and physical discomfort represent obvious barriers to sleep, the psychological dimension of housing instability may be even more fundamental. Sleep requires a basic sense of safety—a normal expectation for people who are stably housed, but for people who are unsheltered or sleeping in a congregate setting with strangers, feeling safe is a luxury that they cannot afford.

For those sleeping rough, hypervigilance is a fundamental survival strategy. The risks are documented and pervasive: theft of their few possessions, physical assault, sexual violence, and harassment by both other unhoused individuals and the housed population [15]. Studies consistently show that unhoused individuals experience victimization at rates far exceeding the general population [16], [17]. In this context, deep sleep represents vulnerability. Many unhoused individuals report sleeping in brief intervals, remaining in a state of heightened alertness, or taking turns with trusted companions to maintain watch over their personal safety and belongings [15]. This protective hypervigilance extracts an enormous toll physically and mentally.

Congregate shelter environments, while offering protection from the heat and providing some security benefits, introduce their own barriers to sleep. Dozens or potentially hundreds of individuals in shared sleeping spaces create noise, disruption, and a need for continued vigilance. For individuals with mental illness or substance use disorders—overrepresented among chronically homeless populations [18]—the behavioral disruptions in congregate settings further fragment sleep for everyone present. Fig. 3 shows a congregate dormitory, and Fig. 4 depicts the shelter environment as rendered by an artist based on shelter client input.

Figure 4.Artist’s rendering of the congregate shelter dormitory environment depicting light-, sound-, safety-, and comfort-related barriers to restful sleep as informed by shelter client input. (Artistic credit: Nick Shekerjian.)

 

Congregate shelter environments, while offering protection from the heat and providing some security benefits, introduce their own barriers to sleep.

Understanding sleep deprivation among unhoused populations in Phoenix and other cities around the world requires examining the structural conditions that create and perpetuate homelessness in the city. While national factors in the United States, like affordable housing shortages, inflation, and inadequate mental health services contribute everywhere [19], Phoenix and its neighboring cities face additional challenges.

The region has experienced explosive population growth, with the city of Phoenix having increased from 1.3 million in 2000 to 1.6 million in 2025 [20] in a metro region population of nearly 5 million. This growth has put pressure on housing costs, with wage stagnation for most low-income workers, creating an impossible affordability challenge for those in the rental market and an explosion in the number of evictions annually [21].

The criminalization of homelessness in the United States following the Supreme Court’s decision in City of Grants Pass v. Johnson, 603 U.S. 520 (2024) compounds these difficulties. Anti-camping ordinances, restrictions on sleeping in vehicles, and enforcement sweeps, such as that which occurred at “The Zone” in Phoenix, destroyed personal property, any sense of community, and exacerbated displacement [22]. The resulting cycle of citations, fines, and warrants creates legal barriers to employment and housing, even when individuals access those opportunities.

The connection between sleep deprivation and prolonged homelessness creates a vicious cycle that existing service systems are poorly designed to interrupt. As explained by Buguet et al. [10], the physiological impacts cascade: chronic heat exposure and sleep deprivation impair cognitive function, decision-making capacity, and emotional regulation—precisely the mental and physical capacities required to navigate the complex bureaucratic systems necessary to secure housing, employment, health care, and other vital services.

Consider the typical path to resolving homelessness in the current U.S. system: an individual must maintain shelter attendance while meeting with case managers, attending mandatory appointments with multiple agencies, completing extensive paperwork (which may or may not be in their native language), maintaining access to documentation, including forms of identification, and often participating in treatment programs or job training. Missing appointments or failing to submit completed documents in a timely fashion can result in loss of housing assistance and/or shelter access.

How do we ensure that technology interventions in shelter settings respect the dignity and autonomy of residents who have limited power to consent or refuse?

For an individual operating on chronic sleep dep-rivation—with cognitive function equivalent to legal intoxication in many cases [23]—successfully managing this complex system becomes nearly impossible. Sleep-deprived individuals are more likely to miss appointments, make poor decisions, are more likely to experience conflict with service providers or potential employers, and struggle with their emotional regulation.

The employment barrier is particularly acute. Job interviews require cognitive sharpness, appropriate social presentation, and emotional control-all severely compromised by sleep deprivation. For those who secure employment, maintaining job performance and attendance while managing homelessness and sleep deprivation proves unsustainable for many. The night shift work, often available to individuals with limited qualifications, can further disrupt sleep patterns and eliminate access to services, the majority of which are only offered during usual business hours.

Moreover, sleep deprivation may compound existing disabilities. Mental health conditions worsen without restorative sleep [24]. Chronic pain intensifies. Diabetes, cardiovascular disease, and other physical health conditions become harder to manage [25].

Given the scale of homelessness and its documented impacts on sleep, health, and functioning, the absence of technological innovation focused on improving conditions for unhoused populations is striking. While the public and private sector [26], [27], [28], [29] has invested billions of dollars to design solutions to reduce homelessness, and the commercial sectors have invested significant sums in sleep optimization technologies—from smart mattresses to sleep tracking apps and sound machines—there is a clear absence of parallel innovation targeting the sleep needs of unhoused individuals.

This gap reflects broader patterns in how technology innovation follows economic incentives rather than social needs, particularly related to vulnerable populations. Yet, the potential for technology to address environmental barriers to sleep in congregate settings or support harm reduction in unsheltered contexts remains largely unexplored.

Sound masking technology offers one example of how existing commercial technologies might be repurposed for shelter environments. These systems, widely deployed in office buildings and call centers to reduce distractions and increase privacy, are an example of how an existing technology could be positively repurposed to address noise disruptions within a shelter space. Rather than attempting to reduce all noise—an impossible goal in congregate settings—sound masking has the potential to create a consistent ambient sound that minimizes the startle effect of sudden noises while making conversations less intelligible, thereby reducing disruption and the anxiety of overhearing conflicts or distressing conversations. Moreover, environmental sound masking technologies do not introduce personal security concerns for individuals who have a history of trauma and must maintain sensory alertness.

Other technologies similarly merit exploration. Climate control systems, such as evaporative cooling systems and radiant cooling panels, optimized for the sleeping environment rather than generic temperature control, could improve sleep quality in shelter dormitories at a lower cost than whole-building air conditioning. Modular privacy solutions, such as curtain systems and panels, that provide acoustic and visual separation without the expense and inflexibility of permanent walls could allow congregate settings to reduce some security anxieties while still providing for staff supervision. Smart lighting systems that support circadian rhythm regulation could help counter the sleep disruption from bright lighting in 24-hour facilities. Some have explored sleeping pods as a solution to privacy and sound concerns. However, such pods are untenable for congregate shelter settings due to hygiene and security concerns, space limitations to shelter growing numbers of people, and economic constraints that characterize the homelessness services reality.

The key questions are not primarily technical but relate to deployment, ethics, and scientific evidence. How do we ensure that technology interventions in shelter settings respect the dignity and autonomy of residents who have limited power to consent or refuse? Who should conduct the pilot studies that provide the evidence of effectiveness—or not—widespread implementation? How can the perspectives of the clients be genuinely incorporated into the research studies rather than assumed? And fundamentally, how do we create incentive structures that direct innovation toward populations defined by a lack of resources rather than an abundance of them?

Recognizing sleep as a fundamental need for individuals trying to escape the vicious cycle of homelessness should reshape how we design and evaluate homeless services.

Recognizing sleep as a fundamental need for individuals trying to escape the vicious cycle of homelessness should reshape how we design and evaluate homeless services. Several principles emerge:

• Environmental optimization. Rather than treating sleep quality as a luxury, shelter design and operation should prioritize conditions that enable restorative sleep. This includes adequate cooling in hot climates, noise reduction strategies, sufficient space between beds, lighting that supports healthy sleep-wake cycles, and policies that allow extended sleep for those who need it.
• Trauma-informed approaches to security. Addressing the hypervigilance that prevents sleep requires creating environments that are genuinely safe. This suggests rethinking shelter design that promotes safety and provides a greater degree of privacy and autonomy.
• Research and innovation focus. The disparity between resources devoted to sleep optimization for housed versus unhoused populations should be addressed through dedicated research funding, incentives for technology companies to experiment and adapt existing solutions, and partnership models that bring together service providers, technology companies, and the research community.
• Climate adaptation strategies. As climate change intensifies heat in Phoenix and Southwestern states more generally, homeless services must develop heat-specific adaptations. This includes extended hours for cooling centers, priority shelter access during extreme heat, investment in cooling technology, and recognition that extreme heat is the leading weather-related cause of death.

Sleep is not a luxury but a fundamental necessity. Yet, the principal approach to homelessness within the United States has been to treat sleep as incidental—a byproduct of having a bed rather than appreciating the importance of the infrastructure to health and well-being.

For unhoused individuals, the inability to get restorative sleep results from the intersection of environmental extremes, institutional design, socioeconomic marginalization, and the psychological toll of insecurity. Addressing this complex interplay requires acknowledging that sleep is both a right and a necessity, while being fundamental to their ability to navigate the complex systems designed to get them rehoused.

Multiple technologies exist to improve sleep quality that merit exploration for congregate settings where personal safety and mitigating hypervigilance are of paramount importance to promote restful sleep as a key component to resolving homelessness. The knowledge exists to design environments that encourage sleep. What has been lacking is the will to apply resources and innovation to a population that cannot advocate for itself. Changing this paradigm requires recognizing that investing in sleep for unhoused individuals is not charity but rather an investment in bolstering individual capacity to support resolving homelessness.

As homelessness continues to rise, exacerbated by intensifying climate change, the need for technological innovation to support social and structural change is becoming increasingly urgent. The question is whether our technological society will extend the benefits of innovation to those who need it most, or whether sleep optimization will remain another amenity available only to those who already have secure housing and the disposable income to access technologies designed to enhance restful sleep. If technology leaders are willing to make investments for segments of society who are often silent in the consumer technology marketplace, we have the opportunity to profoundly impact homelessness by attending to a foundational human need-a good night’s sleep-that is a key component to resolving homelessness.