By Jenni VanDeree, LAT, ATC
Injury Prevention and Ergonomics Specialist, Fit For Work
Key Insights
- Early warning signs of heat illness may seem minor, but they can escalate quickly.
- The effects of heat illness can increase the risk of accidents in the workplace.
- Develop a plan to mitigate heat risks before high temperatures occur.
- Encourage supervisors and employees to know their normal and recognize changes.
Heat illness occurs when the body cannot properly regulate temperature in hot conditions and can develop quickly, so it is essential to recognize the early warning signs. Prompt action and early recognition can prevent progression from the early stages—heat rash and heat cramps—to serious conditions such as heat exhaustion and heat stroke.
10 Early Warning Signs of Heat Illness
Supervisors and employees should be aware of the following 10 early signs of heat illness:
- Muscle pain or cramps, usually in the arms or legs
- Dark or reduced urine output, instead of healthy output that is usually pale yellow or nearly clear
- Headaches that progress to an intense, pounding sensation
- Rapid heart rate or elevated body temperature as the heart works harder, moving blood to the skin to cool the body
- Excessive thirst, indicating significant dehydration
- Excessive sweating, signaling that the body is struggling to regulate temperature
- Nausea or vomiting as blood flow to the stomach is reduced, slowing digestion to prioritize cooling
- Increasing weakness and fatigue as the body struggles to cool itself
- Confusion or difficulty concentrating due to the brain sending blood to major organs for temperature regulation, reducing normal blood flow and function
- Dizziness or fainting, caused by blood pressure dropping due to dehydration and increased load on the heart
If an employee exhibits any of these symptoms, stop and assess the situation. Ask about hydration, recent activity, and how they are feeling. Early intervention is often the most effective way to prevent heat exhaustion or heat stroke.
Safety Risks of Ignoring Early Heat Illness Symptoms
The earliest signs of heat illness are often easy to ignore, but doing so can come at a serious cost. Acting early can mean the difference between an employee requiring a brief cool-down or experiencing a serious medical emergency. Increasing severity of early symptoms signals progression into heat exhaustion, which requires prompt cooling and hydration to avoid rapid escalation to the final stage of heat illness. Heat stroke is life-threatening and can cause permanent damage to vital organs.
The symptoms above also create other hazards. Dizziness, fainting, confusion, and muscle weakness are not only indicators of progressing heat illness; they also put the individual and those around them in danger. In some cases, a heat-related injury can contribute to a secondary event such as a fall, struck-by incident, vehicle accident, or equipment error caused by fatigue, slowed reaction time, or impaired decision-making. Awareness of this increased risk emphasizes how important it is for employers to take a proactive approach toward heat illness prevention.
How Supervisors Can Prevent Heat Illness Before It Escalates
Plan Ahead
What’s the best way to manage and prevent heat illness? Create an action plan before heat hazards occur.
- Understand applicable OSHA regulations and criteria for heat hazards. The Heat National Emphasis Program is creating greater emphasis on heat exposure and heat injury prevention protocols.
- Be aware of weather forecasts and heat advisories. The OSHA-NIOSH Heat Safety Tool is an app that allows workers and supervisors to calculate the heat index for their worksite, and based on the heat index, displays a risk level to outdoor workers.
- Coordinate with leadership on additional resources needed for high temperatures such as water stations, electrolyte packets, shade tents for outdoor work, and additional breaks.
- Plan communication to employees regarding changes or recommendations for work during hot weather.
- Use controls, such as system shutoffs, to ensure employees are taking adequate breaks.
- Establish an acclimatization process for new employees and those returning from extended time away from work. Employees are often at highest risk during their first days back in hot conditions.
- Develop protocols for handling signs of heat illness to promote quick, effective responses to symptoms.
Remember, if an employee is experiencing heat illness, cooling them down quickly is key. Move them to a cooler area and provide water in small, frequent quantities. Removing extra layers of clothing, including shoes and socks, is important. Ice packs or cool cloths applied to the head, neck, chest, and underarms can dramatically improve cooling.
Milder symptoms should show improvement within 30 minutes. However, if symptoms persist or worsen, call 911. When in doubt, treat heat illness as a serious medical emergency.
Know Their Normal
When considering some early signs, it is important to encourage employees to know what is normal for them in order to recognize concerning changes. Some individuals may be prone to sweating more heavily than others, so excessive sweating may look markedly different for them than someone who typically sweats less.
It is also advisable for supervisors to be familiar with what normal looks like for their team members. Be present in work areas and make a point of interacting with employees regularly to keep an eye out for concerning changes.
Educate
Education provides employees with the information and tools to recognize signs of heat illness and take steps to prevent escalation.
- Educate employees about the early warning signs of heat illness during toolbox talks (brief safety meetings focused on a specific workplace hazard) and pre-shift meetings.
- Place signage highlighting the signs of heat illness in prominent areas. For example, post reminders about dark or decreased urine output in or near restrooms.
- Share guidelines on appropriate clothing choices during hot weather; light, looser-fitting garments that allow the skin to breathe and sweat are best.
- Issue reusable water bottles with a hydration handout covering appropriate urine color and best practices for staying hydrated.
- Increase awareness of physical risk and pharmacological risk factors.
Some employees may not realize that they are at higher risk of heat illness due to physical factors or medication. Age, pregnancy, body mass index (BMI), and chronic conditions like high blood pressure, diabetes, or asthma can increase susceptibility to heat illness. Insulin and some pharmaceuticals for treatment of mental health conditions also cause heightened sensitivity to heat. If employees are concerned about being at increased risk, recommend that they consult their healthcare provider.
Conclusion
Heat illness poses a severe risk in the workplace, but acknowledging the early warning signs gives employees the best chance to address heat illness before it becomes a serious medical emergency. Proper planning, awareness of individual norms, and strong educational efforts all contribute to increased awareness and improved risk mitigation. Supervisors who take a strong proactive approach are key to keeping employees safe when working in hot conditions.
Concerned about heat risks in your workplace? Contact Fit For Work to discuss strategies to help protect your workforce and reduce the risk of heat-related injuries.
Jenni VanDeree is an Injury Prevention and Ergonomics Specialist at Fit For Work, where she helps organizations improve workforce health and safety through proactive, data-driven solutions. Based in the Northeast, she is also a member of the Fit For Work continuing education team, contributing to the development of best practices and educational resources across the organization.
Since joining Fit For Work in 2021, Jenni has primarily supported clients in grocery distribution, helping reduce workplace injuries and improve ergonomic outcomes through targeted interventions, employee education, and onsite support. She earned a Bachelor of Science in athletic training from Marist College and is passionate about creating safer, more sustainable work environments through injury prevention and ergonomics excellence.
