Patient presents with symptoms consistent with heat exhaustion, likely secondary to prolonged exposure to high ambient temperatures and strenuous physical activity earlier today.  The patient reports feeling dizzy, lightheaded, and nauseous, accompanied by profuse sweating, muscle cramps in the calves and thighs, and general weakness.  On examination, the patient exhibits tachycardia, mild hypotension, and cool, clammy skin.  Temperature is elevated at 100.9 degrees Fahrenheit orally.  Mental status is currently alert and oriented, though slightly fatigued.  No signs of heat stroke, such as altered mental status or seizures, are observed.  Diagnosis of heat exhaustion is made based on clinical presentation and history.  Treatment plan includes oral rehydration with electrolyte-containing fluids, placement in a cool environment with active cooling measures like cool compresses, and rest.  Patient education provided on the importance of avoiding further heat exposure, recognizing the signs and symptoms of heat-related illness, and proper hydration techniques.  Patient will be monitored for improvement and reevaluated as needed.  Differential diagnoses considered included dehydration, heat syncope, and viral illness.  ICD-10 code T67.0XXA assigned.  CPT codes for evaluation and management services will be determined based on the complexity of the encounter.