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Assessing the Effect of Cool Roofs on Health Using Smartwatches in Colima, Mexico

A Randomized Controlled Trial (RCT) Evaluating the Effects of Cool Roofs on Health Outcomes Using Smartwatches in Colima, Mexico

Status
Not yet recruiting
Phases
Unknown
Study type
Interventional
Source
ClinicalTrials.gov
Registry ID
NCT06831006
Acronym
REFLECT
Enrollment
800
Registered
2025-02-17
Start date
2026-04-01
Completion date
2027-09-01
Last updated
2026-03-11

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Active Minutes, All-day Steps, Awake Duration, Distance Walked, Heart Rate, Moderate-intensity Activity Minutes, Sleep Quantity, Sleep Score, Time in Sleep Stages, Vigorous-intensity Activity Duration

Keywords

Hot Temperature, Humidity, Housing, Wearable, Smartwatch, Heart rate, Cardiovascular, Physical activity, Sleep, Cool roof, Heat stress

Brief summary

Ambient air temperatures in Mexico have broken record highs in 2024. Solutions are needed to build heat resilience in communities and adapt to increasing heat from climate change. Sunlight-reflecting cool roof coatings may passively reduce indoor temperatures and energy use to protect home occupants from extreme heat. Occupants living in poor housing conditions in the northern zone of Mexico are susceptible to increased heat exposure. Heat exposure can instigate and worsen numerous physical, mental and social health conditions. The worst adverse health effects are experienced in communities that are least able to adapt to heat exposure. By reducing indoor temperatures, cool roof use may promote heart health, sleep and physical activity in household occupants. The long-term research goal of the investigators is to identify viable passive housing adaptation technologies with proven health benefits to reduce the burden of heat stress in communities affected by heat in Mexico. To meet this goal, the investigators will conduct a randomized controlled trial to establish the effects of cool roof use on heart rate, sleep and physical activity in Colima, Mexico.

Detailed description

Increasing heat exposure from climate change is causing and exacerbating heat-related illnesses in millions worldwide - particularly in low-resource settings. June 2024 was the 13th consecutive hottest month on record globally - shattering previous records. Heat exposure can instigate and worsen health conditions, including cardiovascular, metabolic, endocrine and respiratory disease, heat-related illnesses, pregnancy complications, and mental health conditions. Adaptation is essential for protecting people from increasing heat exposure. The built environment, especially homes, is ideal for deploying interventions to reduce heat exposure and accelerate adaptation efforts. However, there currently is a lack of evidence on a global scale - generated through empirical studies - guiding the uptake of interventions to reduce heat stress in low-resource settings. Cities and towns of LMIC are among the most vulnerable to the adverse impacts of climate change and are likely to experience increases in ambient air temperature over the coming decades. People in Colima are exposed to heat and low humidity year-round. The combined burden of heat and NCDs places Colima's population at greater risk of adverse health effects from heat extremes. Sunlight-reflecting cool roof coatings passively reduce indoor temperatures and lower energy use, offering protection to home occupants from extreme heat. The investigators therefore aim to conduct a randomized controlled trial investigating the effects of cool roofs on heart rate, sleep and physical activity using smartwatches in Colima. The trial will quantify whether cool roofs are an effective passive home cooling intervention with beneficial health effects for vulnerable populations in Colima. Findings will inform regional and global policy responses on scaling cool roof implementation to protect people from increasing heat exposure driven by climate change.

Interventions

Cool roofs are a heat-reflecting material that can be applied to existing household roofing in the form of a liquid-applied membrane. Cool roofs work by increasing solar reflectance (the ability to reflect the visible wavelengths of sunlight, reducing heat transfer to the surface) and thermal emittance (the ability to radiate absorbed solar energy) thereby reducing the amount of heat transferred into the home.

Sponsors

University of Auckland, New Zealand
Lead SponsorOTHER
Heidelberg University
CollaboratorOTHER
London School of Hygiene and Tropical Medicine
CollaboratorOTHER
Rutgers University
CollaboratorOTHER
Labfront
CollaboratorINDUSTRY
Wellcome Trust
CollaboratorOTHER
EPS
CollaboratorUNKNOWN
Universidad de Colima
CollaboratorOTHER

Study design

Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
PREVENTION
Masking
DOUBLE (Investigator, Outcomes Assessor)

Masking description

Trial participants will be aware of the intervention to which they have been allocated, and the research fieldworkers will be aware of the intervention allocation. The trial steering committee members and trial statistician will remain blinded until the end of trial period and data collection.

Eligibility

Sex/Gender
ALL
Age
18 Years to No maximum
Healthy volunteers
Yes

Inclusion criteria

* Permanent household resident

Exclusion criteria

* Roof damage, inaccessible or instability of roof adversely affecting cool roof coating application. * Participant unable to provide written/verbal informed consent. Participants will be excluded if they are not willing or able to wear a smartwatch. * Participants will be excluded if they do not have a smartphone with an internet connection that can connect to the smartwatch. * Only one participant per household.

Design outcomes

Primary

MeasureTime frameDescription
Heart rateSmartwatches will be worn for two consecutive weeks per month. Eight measurement points will be taken: one at baseline and seven over 12 months, covering three consecutive hottest months and four alternate months.Heart rate in beats per minute measured at 15-second intervals using Garmin Vivosmart 5 devices.

Secondary

MeasureTime frameDescription
All-day stepsSmartwatches will be worn for two consecutive weeks per month. Eight measurement points will be taken: one at baseline and seven over 12 months, covering three consecutive hottest months and four alternate months.The number of steps measured daily using Garmin Vivosmart 5 devices.
Active minutesSmartwatches will be worn for two consecutive weeks per month. Eight measurement points will be taken: one at baseline and seven over 12 months, covering three consecutive hottest months and four alternate months.The total number of minutes of active exercise daily using Garmin Vivosmart 5 devices.
Distance walkedSmartwatches will be worn for two consecutive weeks per month. Eight measurement points will be taken: one at baseline and seven over 12 months, covering three consecutive hottest months and four alternate months.The total distance walked daily using Garmin Vivosmart 5 devices.
Moderate-intensity activity minutesSmartwatches will be worn for two consecutive weeks per month. Eight measurement points will be taken: one at barements will be taken continuously for 12 months. Participants will be asked to wear their smartwatch for at least two weeks every month.The total number of minutes of moderate-intensity activity daily using Garmin Vivosmart 5 devices.
Vigorous-intensity activity durationSmartwatches will be worn for two consecutive weeks per month. Eight measurement points will be taken: one at baseline and seven over 12 months, covering three consecutive hottest months and four alternate months.The total number of minutes of vigorous-intensity activity daily using Garmin Vivosmart 5 devices.
Sleep quantitySmartwatches will be worn for two consecutive weeks per month. Eight measurement points will be taken: one at baseline and seven over 12 months, covering three consecutive hottest months and four alternate months.The number of hours spent asleep each night using Garmin Vivosmart 5 devices.
Time in sleep stagesSmartwatches will be worn for two consecutive weeks per month. Eight measurement points will be taken: one at baseline and seven over 12 months, covering three consecutive hottest months and four alternate months.The number of hours spent in sleep stages each night using Garmin Vivosmart 5 devices.
Awake durationSmartwatches will be worn for two consecutive weeks per month. Eight measurement points will be taken: one at baseline and seven over 12 months, covering three consecutive hottest months and four alternate months.The number of hours spent awake during sleep time each night using Garmin Vivosmart 5 devices.
Sleep scoreSmartwatches will be worn for two consecutive weeks per month. Eight measurement points will be taken: one at baseline and seven over 12 months, covering three consecutive hottest months and four alternate months.The Garmin sleep score (0-100) each night using Garmin Vivosmart 5 devices. A higher score means a better outcome.

Countries

Mexico

Contacts

CONTACTAditi Bunker, Dr
aditi.bunker@uni-heidelberg.de+49 6221 565344
CONTACTCollin Tukuitonga, Sir. Dr.
collin.tukuitonga@auckland.ac.nz+6493737599
PRINCIPAL_INVESTIGATORCollin Tukuitonga, Sir. Dr.

University of Auckland, New Zealand

Outcome results

None listed

Source: ClinicalTrials.gov · Data processed: Mar 12, 2026