Beat the Heat: Recognize Signs of Heat Illness

Several types of heat-related illnesses can affect workers and symptoms may be non-specific. When a worker is performing physical labor in warm environments, any unusual symptom may be a sign of heat illness. The chart below from OSHA outlines symptoms and signs that may indicate heat stress. Note that common signs and symptoms include muscle pain, weakness or fatigue, dizziness, heavy sweating, and rapid heart rate. 

Heat-Related Illness 

Symptoms and Signs 

Heat stroke 

  • Confusion 
  • Slurred speech 
  • Unconsciousness 
  • Seizures 
  • Heavy sweating or hot, dry skin 
  • Very high body temperature 
  • Rapid heart rate 
Heat exhaustion 
  • Fatigue 
  • Irritability 
  • Thirst 
  • Nausea or vomiting 
  • Dizziness or lightheadedness 
  • Heavy sweating 
  • Elevated body temperature or fast heart rate 
Heat cramps 
  • Muscle spasms or pain 
  • Usually in legs, arms, or trunk 
Heat syncope 
  • Fainting 
  • Dizziness 
Heat rash 
  • Clusters of red bumps on skin 
  • Often appears on neck, upper chest, and skin folds 
Rhabdomyolysis (muscle breakdown) 
  • Muscle pain 
  • Dark urine or reduced urine output 
  • Weakness 

 

Employers and workers should become aware of symptoms related to heat stress and heat illness. In addition, knowing what to do when someone is showing signs of heat illness is very important. This resource from NIOSH describes the appropriate first aid for each of these illnesses. Prompt action to provide first aid can make a difference in recovery of persons with heat illness. Multiple heat-related illnesses can occur together, and time is of the essence.  

When in doubt, place the worker in a cool environment and call 911.