Assessing the Effect of Cool Roofs on Health Using Smartwatches in Niue

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.

Pacific Islands and other small island developing states 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 Niue are exposed to heat and humidity year-round. The Pacific Islands have a large burden of non-communicable diseases (NCDs), with nearly three-quarters of deaths due to NCDs. The combined burden of heat and NCDs places Pacific Island populations 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 Niue.

The trial will quantify whether cool roofs are an effective passive home cooling intervention with beneficial health effects for vulnerable populations in Niue. Findings will inform regional and global policy responses on scaling cool roof implementation to protect people from increasing heat exposure driven by climate change.

Inclusion criteria

Participant criteria:

• Consenting adult aged 18 years and over.
• Expected to be available to participate in the study for at least nine months in the next 12 months.
• Willing and able to wear a smartwatch.

Household criteria:

• House has a metal roof.
• House is single-story.

Exclusion criteria

Participant criteria:

• One participant per household
• Does not have a smartphone with an internet connection that can connect to the smartwatch.

Household criteria:

• Unstable house structure that does not permit the application of cool roof materials.
• Inaccessible by the research team.
• Significant roof damage defined as any penetrative roof defect that results in a hole in the roof OR over 25% of the roof rusted.