An Evidence-Based Wearable Intervention to Improve Sun-Safety Awareness and Support Overall Cognitive Well-Being
ABSTRACT
This three-phase study presents the systematic design and validation of a wearable Ultraviolet (UV) monitoring and awareness intervention designed to bridge the gap between sun safety knowledge and protective behaviors. Phase 1 surveyed 98 adolescents, revealing that despite 60.2% reporting sunscreen use, only 25.4% reapplied as recommended, with forgetfulness and texture concerns as primary barriers. These findings informed Phase 2 in which we developed the UV Tracker, a wearable device that measures real-time UV exposure and translates it into an estimated Vitamin D value. Phase 3 surveyed 30 participants, finding low confidence in UV exposure estimation (M = 3.07/7) and minimal tracking behaviors (M = 2.47/7) despite high UV knowledge (M = 5.93/7) gaps directly addressed by the UV Tracker. Device acceptance was moderate (40% positive), with validation being critical for adoption. This evidence-based approach demonstrates how the proposed wearable UV-monitoring intervention influences behavioral barriers related to UV exposure and supports skin-health practices associated with skin-cancer prevention and overall cognitive well-being.
INTRODUCTION.
Regular sunscreen use is one of the most effective preventive measures against Ultraviolet (UV) induced skin damage and skin cancer development.1,2 The American Academy of Dermatology recommends using broad-spectrum sunscreen with a sun protection factor (SPF) of at least 30, applying it 15-30 minutes prior to sun exposure, with reapplication every two hours or after swimming or sweating to maintain effective photoprotection.3 However, despite decades of clear guidelines and widespread public health campaigns, sunscreen adherence among adolescents remains suboptimal on a global scale.4,5
Adolescence represents a developmentally critical period for establishing lifelong health behaviors. Yet, individuals in this age group frequently exhibit low perceived personal susceptibility to skin cancer and prioritize immediate concerns such as appearance over long-term health outcomes. Previous research has identified various barriers to sunscreen use, including cost, poor sensory attributes (e.g., texture, residue, scent), forgetfulness, and limited access to suitable products. However, there is a continued lack of detailed behavioral data characterizing sunscreen usage patterns among adolescents aged 14-18 years in the United States, particularly focusing on the specific obstacles that prevent consistent use.
These behavioral and product-related barriers highlight a critical gap between knowledge and action. Although many adolescents are aware of sun-safety recommendations, they often fail to consistently apply sunscreen due to factors such as forgetfulness, inconvenience, and dissatisfaction with product characteristics. Phase 1 of this study further supports this gap, with 60.2% of participants reporting sunscreen use but only 25.4% reapplying it at recommended intervals.
Ultraviolet exposure differs from many other health risks in that it occurs continuously throughout daily activities rather than as a single isolated event. Although UV index forecasts are widely available, these measurements represent generalized environmental conditions across a broad geographic area and may not accurately reflect an individual’s real-time exposure based on their exact location, movement, and behavior. As a result, individuals often lack personalized feedback regarding their cumulative UV exposure during the day. Wearable UV monitoring technologies provide an opportunity to address this limitation by offering real-time, location-specific exposure information that can support more informed sun-protection decisions.6
Ultraviolet (UV) exposure is strongly associated with skin cancer, which remains the most common form of cancer in the United States, with approximately 5.4 million cases of basal cell and squamous cell carcinomas diagnosed each year. Melanoma—the deadliest form of skin cancer—accounts for over 100,000 new cases annually.7 UV radiation exposure, particularly during childhood and adolescence, is a well-established risk factor for developing skin cancer later in life. Beyond dermatological outcomes, UV exposure also plays a broader role in overall health through its contribution to Vitamin D synthesis.8 Adequate Vitamin D levels are increasingly linked to cognitive functioning, with emerging evidence suggesting associations between Vitamin D deficiency and an elevated risk of cognitive impairment, including dementia and other neurodegenerative conditions.9 Thus, understanding and managing UV exposure has important implications not only for skin-cancer prevention but also for supporting long-term cognitive well-being.
To address these behavioral and product-related barriers, this study proposes a wearable UV-monitoring device designed to provide real-time, personalized exposure feedback. Unlike generalized UV index forecasts, which do not reflect individual movement and behavior, this device continuously tracks actual UV exposure throughout daily activities. By directly addressing barriers such as forgetfulness and lack of real-time awareness, the device reduces reliance on memory-based sunscreen use and enables more informed sun-protection decisions.
This study builds upon identified behavioral and product-related barriers by integrating engineering design with user-centered evaluation. First, this study identifies key barriers that contribute to inconsistent sunscreen use among adolescents. Second, it presents the design and development of a wearable device capable of measuring real-time UV exposure to overcome these barriers. Third, it evaluates the performance and accuracy of the device. Finally, it examines user acceptance and whether real-time feedback can improve UV awareness and sun-protection behaviors.
METHODS.
This study employed a three-phase design integrating behavioral analysis with engineering development. Phase 1 identified behavioral and product-related barriers to sunscreen use through adolescent surveys. Phase 2 focused on the iterative design and construction of a wearable UV monitoring device. Phase 3 evaluated device performance and user acceptance through deployment and validation testing.
Hardware Design of the UV Tracker.
The UV Tracker was developed through multiple iterative hardware design cycles within a user-centered design framework, as illustrated in Figure 1. Each iteration addressed limitations identified in previous designs while targeting key behavioral barriers, including forgetfulness and the lack of real-time awareness of UV exposure.
The initial iteration consisted of a conceptual paper prototype used to evaluate ergonomic placement and exposure consistency (Figure 1a). Testing revealed that natural wrist movement caused partial sensor obstruction, limiting the device’s ability to capture continuous UV exposure and reducing measurement reliability.
The second iteration introduced a low-fidelity electronic prototype integrating the ESP32-S3 Zero microcontroller and LTR390 UV sensor (Figure 1b). While this configuration enabled real-time data collection, initial testing demonstrated variability in UV readings of approximately ± 1.2 UV index units, primarily due to inconsistent sensor orientation and environmental interference.
Subsequent refinements focused on improving sensor positioning and stability. In the third iteration, the sensor was repositioned to the upper surface of the wristband to maximize direct exposure to ambient UV radiation. This modification reduced obstruction effects and improved measurement consistency, decreasing variability to approximately ± 0.5 UV index units.
Final iterations emphasized durability, structural stability, and sustained exposure accuracy under real-world conditions (Figure 1c). The resulting design ensured continuous, unobstructed UV detection during daily activities while maintaining user comfort and wearability, directly supporting the goal of providing reliable real-time feedback to overcome behavioral barriers.
The UV Tracker prototype was designed as a wrist-mounted wearable device intended to measure real-time ultraviolet exposure during daily outdoor activities. Sensor placement was carefully considered to maximize direct exposure to ambient sunlight while minimizing obstruction from clothing or natural arm movement. The LTR390 ultraviolet sensor was positioned on the upper surface of the wristband to reduce shadowing effects and ensure consistent exposure to environmental UV radiation. The ESP32-S3 Zero microcontroller manages sensor communication, data processing, and wireless transmission to a cloud-based interface where users can view their UV exposure data.
Software Design.
The UV Tracker was programmed using Arduino IDE on an ESP32-S3 Zero microcontroller,10 selected for its compact size, low power consumption, and integrated Wi-Fi capabilities, making it well-suited for continuous wearable operation.
The system was designed to collect ultraviolet (UV) measurements at 3-second intervals, process sensor data, and convert raw outputs into standardized UV index values. These values are then transmitted via Wi-Fi to a cloud-based database, enabling real-time data access through a web-based dashboard interface. Compared to alternative platforms such as Raspberry Pi, the ESP32 provides efficient real-time processing with significantly lower power requirements, allowing for extended device operation without compromising portability or thermal stability.
The device operates through a continuous sensing loop: it acquires UV sensor readings, converts the data into UV index values, compares exposure levels against predefined thresholds, and activates corresponding LED indicators (green for low, orange for moderate, and purple for high exposure). Simultaneously, data are transmitted wirelessly for remote monitoring and user access. This process is implemented as a continuous loop-based system for real-time data acquisition and feedback.
Calibration and Validation.
Controlled calibration experiments were conducted to evaluate the accuracy of the UV Tracker sensor readings relative to reference UV measurements, as shown in Figure 2. During testing, the wearable UV sensor was exposed to varying ultraviolet light intensities while simultaneously recording readings from a reference UV measurement system. The LED feedback system was calibrated by iteratively adjusting threshold values used to map sensor readings to UV index categories. These adjustments ensured that the color-coded LED indicators corresponded to recognized UV index exposure ranges and improved the clarity of real-time exposure feedback.
The calibrated system demonstrated strong agreement with reference UV measurements, with a correlation coefficient exceeding 0.90 and an average deviation of approximately ± 0.5 UV index units.
Deployment.
The UV Tracker devices were deployed to participants for field testing. Participants were instructed to wear the device during outdoor activities and were provided training on device operation, charging procedures, and data interpretation. Device measurements demonstrated strong agreement with reference UV index values (r > 0.90).
Survey Methods.
A structured questionnaire was developed to assess multiple dimensions of sunscreen use behavior. Participants were recruited from a high school community in Las Vegas, Nevada, a region characterized by high annual ultraviolet exposure. Participants were asked to provide demographic information, including age, gender, and race/ethnicity. Sunscreen usage was measured regarding current use, while education was assessed by determining whether participants had received instruction on proper sunscreen application. Sun exposure was evaluated by asking participants to report their average daily hours outdoors during peak UV periods on both weekdays and weekends. The survey also explored application habits, including frequency, timing, and amount of sunscreen applied, as well as the typical sun protection factor of the sunscreen used. Finally, participants were asked to indicate the primary barriers to prevent or limit their sunscreen use.
Both descriptive and inferential statistics were calculated for all variables, including frequencies, percentages, means, and standard deviations where appropriate. In addition, categorical responses were grouped thematically to identify patterns in barriers to sunscreen use.
RESULTS.
The UV Tracker demonstrated strong agreement with reference UV measurements across testing conditions. The device achieved a correlation coefficient exceeding 0.90 when compared to standard UV index measurements. Measurement variability was reduced from approximately ± 1.2 UV index units in early prototypes to ± 0.5 UV index units in the final design. The device was able to continuously capture real-time UV exposure during outdoor activities and provide immediate feedback through LED indicators and a cloud-based interface.
Behavioral Findings.
Despite 60.2% of participants reporting sunscreen use, only 25.4% reapplied at recommended intervals, indicating a significant gap between knowledge and behavior.
Barriers to Sunscreen.
Participants identified a range of barriers to sunscreen use, with the most reported shown in Table 1. Notably, sensory concerns, including texture, smell, and discomfort accounted for 38.8% of all reported barriers, suggesting that product formulation and sensory properties are key determinants of sunscreen adherence among adolescents.
| Table 1. Reported Barriers to Sunscreen Use (n = 98). | ||
| Barrier/Reason | n (%) | Description |
| Texture/Feel issues | 23 (23.5%) | Dislike of texture, concerns about white cast or residue, complaints that sunscreen does not rub in properly |
| Forgetfulness/Laziness | 20 (20.4%) | Forgetting to apply, laziness, insufficient time, or simply not wanting to apply |
| Unavailability of sunscreen | 12 (12.2%) | Sunscreen was not accessible when needed |
| Discomfort/Pain | 10 (10.2%) | Discomfort or pain in the eyes or on skin |
| Perceived unnecessary | 7 (7.1%) | Belief that sunscreen is not needed due to limited sun exposure, not burning easily, or wanting to tan |
| Smell | 5 (5.1%) | Objecting to the scent of sunscreen products |
| Regular users | 9 (9.2%) | Indicating regular sunscreen use with no barriers |
Overall, the findings demonstrate that the UV Tracker provides accurate and reliable real-time UV measurements while identifying key behavioral barriers to sunscreen use among adolescents.
DISCUSSION.
The results demonstrate that the UV Tracker is capable of accurately measuring real-time UV exposure and providing reliable feedback to users. The strong agreement with reference UV measurements (r > 0.90) supports the technical validity of the device as a wearable monitoring tool.
Survey findings identified several behavioral barriers to sunscreen adherence among adolescents, including sensory concerns, forgetfulness, and limited accessibility. These findings highlight a persistent gap between sun-safety knowledge and consistent protective behaviors. The identification of these barriers directly informed the design of the UV Tracker, which provides real-time exposure feedback to support more informed sun-protection decisions.
The integration of real-time UV monitoring provides a practical approach to addressing behavioral barriers such as forgetfulness and lack of awareness. Unlike traditional educational interventions, which rely on memory and self-motivation, the UV Tracker offers continuous feedback that enables users to make immediate and informed decisions about sun protection.
Participants reported moderate acceptance of wearable UV monitoring technology, with 40% expressing positive sentiment toward device accuracy. While this suggests openness to adopting such technology, it also highlights the importance of establishing trust in measurement reliability for widespread use.
By providing real-time UV exposure feedback, the device has the potential to reduce reliance on memory-based sunscreen application and improve reapplication behaviors. This approach directly addresses the gap between knowledge and action identified in the study and may support more consistent sun-protection practices over time.
While UV exposure contributes to Vitamin D synthesis, uncertainty regarding optimal exposure levels suggests a need for balanced sun-protection strategies. The UV Tracker may support this balance by providing individualized exposure data.
These findings demonstrate that integrating wearable UV monitoring with behavioral insights provides a promising approach to improving sun-safety awareness and addressing limitations of traditional prevention strategies.
CONCLUSION.
This study investigated behavioral and product-related barriers to sunscreen use among adolescents and developed a wearable UV monitoring device to address these challenges. The findings demonstrate that the UV Tracker is capable of accurately measuring real-time UV exposure, with strong agreement to reference UV measurements (r > 0.90), while also addressing key barriers such as forgetfulness and lack of awareness.
By integrating behavioral insights with real-time feedback, the device provides a practical approach to improving sun-protection behaviors and reducing reliance on memory-based sunscreen applications. These results highlight the potential of wearable technology to bridge the gap between knowledge and action in preventive health practices. Future work should focus on long-term deployment, expanded user testing, and further refinement of device accuracy and usability to support broader adoption and sustained behavioral impact.
LIMITATIONS.
Several limitations of this study should be acknowledged. First, the use of a sample may limit the generalizability of the findings to broaden adolescent populations. Second, the reliance on self-reported data introduces the potential for social desirability bias, which may lead to overestimation of actual sunscreen use. Third, the cross-sectional design of the study prevents assessment of causality or temporal relationships. Additionally, although calibration experiments demonstrated strong agreement with reference UV measurements, further validation across diverse environmental conditions and longer deployment periods is necessary to fully evaluate the performance and usability of the wearable UV monitoring system.
ACKNOWLEDGMENTS.
The author thanks all participants for their willingness to contribute their time and responses to this project.
REFERENCES.
- Green, G. M. Williams, V. Logan, G. M. Strutton, Reduced melanoma after regular sunscreen use: randomized trial follow-up. Journal of Clinical Oncology. 29, 3, 257–263 (2011).
- Petersen, H. Wulf, Application of sunscreen theory and reality. Photodermatology. Photoimmunology & Photomedicine. 30, 96–101 (2014).
- American Academy of Dermatology, Sunscreen FAQs. American Academy of Dermatology, 2024. Accessed November 1, 2025. https://www.aad.org/media/stats-sunscreen
- Køster, C. Thorgaard, A. Philip, I. Clemmensen, Prevalence of sunburn and sun-related behavior in the Danish population: a cross-sectional study. Scandinavian Journal of Public Health. 38, 5, 548–552 (2010).
- K. Robinson, D. S. Rigel, R. A. Amonette, Trends in sun exposure knowledge, attitudes, and behaviors: 1986 to 1996. Journal of the American Academy of Dermatology. 37, 2 Pt 1, 179–186 (1997).
- G. Parsons, E. S. Nagelhout, A. P. Wankier, et al., Reactivity to UV radiation exposure monitoring using personal exposure devices for skin cancer prevention: longitudinal observational study. Journal of Medical Internet Research.9,9 (2021).
- Holman, Z. Berkowitz, G. Guy Jr, et al., The association between demographic and behavioral characteristics and sunburn among U.S. adults: National Health Interview Survey, 2010. Preventive Medicine. 63, 6–12 (2014).
- R. Webb, B. R. DeCosta, M. F. Holick, Sunlight regulates the cutaneous production of vitamin D3 by causing its photodegradation. Journal of Clinical Endocrinology and Metabolism. 68, 882-887 (1989).
- F. Holick, Vitamin D deficiency. The New England Journal of Medicine. 357, 266-281 (2007).
- Shedboy71, LTR390 UV Light Sensor and ESP32 Board Example. Accessed October 9, 2025. https://www.esp32learning.com/code/ltr390-uv-light-sensor-and-esp32-board-example.php.
Posted by buchanle on Thursday, May 14, 2026 in May 2026.
Tags: Adolescents, barriers to adherence, health behaviors, skin cancer prevention, sunscreen use