What is the most important reason that firefighters must be physically fit?

Firefighters must be physically fit primarily because emergencies are unpredictable and can happen at any time. This unpredictability necessitates that firefighters maintain a high level of physical readiness to respond effectively and efficiently to crises. In such situations, their physical fitness directly impacts their ability to perform demanding tasks, such as carrying heavy equipment, maneuvering through hazardous environments, and executing rescue operations under stressful conditions.

While coordination and physical fitness requirements are relevant to the job, the critical factor is the necessity to be prepared for emergencies as they arise. The nature of firefighting demands readiness; thus, a firefighter's physical preparedness can mean the difference between life and death, both for them and those they are trying to save. Simply having guidelines or requirements does not substitute for the need for a state of constant physical readiness.