MNRF-AFFES has developed a heat stress guideline called the “Heat Illness Prevention Guide” and Hot Weather Plan. However, that relies largely on educational training about heat stress, and supervisor or individual self-monitoring for heat stress symptoms, which is not an optimal prevention strategy according to the hierarchy of controls. Further, it is recognized that individual variations (including sex differences) cause different people to experience the risk of health stress illnesses differently despite the same level of heat stress. The current Guide cannot take account of these considerations. In 2022, CROSH created a Report for AFFES summarizing the measurements and devices used to detect heat strain in wildland Firefighters. This report identified opportunities for continuous monitoring and periodic screening in the context of the current Guide and ACGIH guidelines Five Summary Recommendations were presented from this Report. Based upon discussion with AFFES/MNRF, recommendations two were believed to have the largest potential to effect change, without inducing undue burden to AFFES finances, human resources, or legal expertise (i.e., relating to personal data management). Therefore, the current project aims to develop an AFFES-Specific approach to personal monitoring, which if successful, would be used to modify the AFFES Heat Illness Prevention Guide, to incorporate personal, periodic, Heart Rate (HR) Monitoring and Symptom monitoring into the Hot Weather Plan.