Can a text message save lives in a heat wave?

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria: The Heat Smart randomized controlled trial study will recruit patients and primary care providers (PCPs) from Eastern Ontario. The inclusion criteria ensure that the intervention reaches at-risk individuals while being scalable across different patient populations: Primary Care Patients: * Adults (18 years and older) * Patients must be registered with a participating PCP. * They must have had at least one visit with their PCP in the past two years to ensure active engagement. * Participants must have an active email, cell phone or messaging service (SMS) to receive Heat Smart digital messages. * Patients must be able to understand and consent to participate in the study. * Patients must be able to communicate in at least one of the official languages (English, French). * Participants will be recruited from PCP located in two Eastern Ontario public health districts: the Eastern Ontario Health Unit and Ottawa Public Health (including urban, rural, and Indigenous communities such as Akwesasne). Primary Care Providers: * Must be a licensed Family Physician (FP) or Nurse Practitioner (NP) in a practice of at least 2 PCPS. * The providers must be offering comprehensive primary care to a panel of patients (not solely urgent care or walk-in services). * Must work in a computerized primary care clinic with an electronic medical record system. * Must expect to remain in practice for at least 24 months. * Must be located in Eastern Ontario. * Must be willing to use the Canadian Primary Care Information Network (CPIN) to deliver Heat Smart messages and surveys. * Must be using Cliniconex or Qualtrics as a practice tool for communication enabling outreach before the patients are invited to consent to participate in the study. Exclusion Criteria: Patients who do not read French or English will be excluded from the study as they will not be able to give informed consent or to fill out the surveys. Patients who do not have an email address or text messaging service will be excluded for the same reason. Minors, patients with dementia and people who cannot read and write in English or French will not be eligible because the automated approach to surveying patients makes it impractical to properly obtain their consent.