Heat Illness in the Workplace: What Employers and Employees Need to Know

By: Dr. Pamela Rizza, Chief Medical Officer

As temperatures climb this summer across Colorado, Arizona, and Nevada, heat-related illness becomes one of the most serious and preventable occupational health risks workers face. Just look at the consequences of the recent heat-wave in Europe to understand the dangers involved when temperatures rise and adequate policies and understanding of the risks are lacking. 

Whether your team works outdoors under direct sun or inside a facility without adequate cooling, heat exposure can escalate quickly from discomfort to a medical emergency. 

Understanding how to prevent heat illness, recognize its warning signs, and respond appropriately is essential for maintaining a safe, productive workforce. 

Heat-related illnesses occur when the body cannot cool itself effectively. They exist on a spectrum, ranging from mild conditions like heat cramps and heat exhaustion to life-threatening emergencies like heat stroke. Understanding where a person falls on that spectrum is critical to delivering an appropriate response. 

Heat Cramps 

Painful muscle spasms, usually in the legs or abdomen, that occur during or after strenuous activity in the heat. Often a sign that the body is losing fluids and electrolytes faster than they are being replaced. 

Heat Exhaustion 

A more serious condition characterized by heavy sweating, weakness, cold or pale skin, a fast and weak pulse, nausea, and possible fainting. Heat exhaustion requires prompt intervention, including moving the affected person to a cool area, removing excess clothing, and providing fluids. Taking action in this stage can help prevent more serious health consequences from occurring.  

Heat Stroke 

The most severe form of heat illness, heat stroke is a medical emergency. Symptoms include a core body temperature above 103 degrees Fahrenheit, altered level of consciousness ranging from confusion to becoming unresponsive, hot/dry/reddened skin, and a rapid bounding pulse. Call 911 immediately if heat stroke is suspected. Attempt to relocate to a cooler environment and begin cooling measures as described below. Do not leave the affected person unattended. Failure to respond rapidly to signs of heat stroke can result severe medical consequences including kidney failure, neurologic damage and eventually death.  

Employers are responsible for providing a work environment that does not pose a recognized hazard to employee health and safety. When it comes to heat, that responsibility is both a legal and a practical one. High-heat environments in states like Arizona and Nevada, or during Colorado summers, require deliberate, documented prevention strategies. 

Employers are responsible for providing a work environment that does not pose a recognized hazard to employee health and safety. When it comes to heat, that responsibility is both a legal and a practical one. High-heat environments in states like Arizona and Nevada, or during Colorado summers, require deliberate, documented prevention strategies. 

Develop a Written Heat Illness Prevention Plan 

A heat illness prevention plan should outline procedures for cool fluids and shade access, rest schedules, emergency response, and how supervisors will monitor conditions throughout the day. The plan should be reviewed and updated before the start of high-heat season each year. 

Prioritize Acclimatization for New and Returning Workers 

The body needs time to adjust to working in hot conditions, a process called acclimatization. The body takes roughly 2 weeks to maximize its self-cooling mechanisms when exposed to significant changes in climate. New employees and workers returning from extended leave are at significantly higher risk during their first days on the job. OSHA recommends a gradual ramp-up schedule, starting with shorter exposures to heat and increasing duration over seven to fourteen days. 

Enforce Water, Rest, and Shade Protocols 

The foundation of any heat illness prevention program is straightforward: water, rest, and shade. Employers should ensure: 

• Workers have access to cool drinking water at all times, ideally one quart per hour during high-heat conditions 

• Rest breaks are scheduled regularly and are not skipped during peak heat hours 

• Shade or cooled indoor areas are available and accessible without barriers 

Train Supervisors to Recognize and Respond to Heat Illness 

Supervisors are often the first to observe signs of heat illness in a worker. Training should cover how to identify symptoms at each stage, how to initiate emergency response, and how to document incidents for both OSHA recordkeeping and workers’ compensation purposes. Simply put, severe fatigue and altered mental status in a laborer working in the heat is a heat illness event until proven otherwise. Partnering with an occupational health provider like MBI ensures your supervisors have access to current, evidence-based guidance. 

Understand State-Specific Compliance Requirements 

Heat illness regulations vary by state. Arizona and Nevada have specific heat safety guidelines that employers in industries like construction, agriculture, and logistics should follow. Colorado employers should stay current with the guidance from neighboring states, particularly during extended heat events. HR teams and safety managers should review these requirements annually and consult an occupational health partner for support navigating documentation and reporting obligations. 

Even when employers have strong heat safety programs in place, individual workers are at the forefront of protecting themselves and their coworkers. Knowing the risk, recognizing symptoms early, and speaking up when something feels wrong can prevent a minor heat reaction from becoming a serious medical event. 

Know Your Personal Risk Factors 

Some individuals are more vulnerable to heat illness than others. Risk factors include: 

• Being new to working in hot environments or returning after time away 

• Certain medications that affect sweating or hydration (stimulants, decongestants) 

• Underlying health conditions such as heart disease, diabetes, or obesity 

• Alcohol consumption, even the night before a shift 

• Poor sleep or dehydration coming into a shift 

• Recent illness or infection, especially causing fever 

Stay Hydrated Before, During, and After Your Shift 

Do not wait until you are thirsty to drink water. By the time thirst sets in, you are likely already mildly dehydrated. Drink water consistently throughout your shift, avoid sugary or caffeinated beverages as your primary source of hydration, and consider electrolyte replacement like a low sugar sports drink during extended high-heat exposure. 

Recognize Early Warning Signs and Act on Them 

Do not dismiss early symptoms like headache, dizziness, mental fogginess, muscle cramps, or feeling unusually fatigued. These are signals that your body is struggling to manage heat. Report how you are feeling to a supervisor immediately, move to a shaded or cooled area, and hydrate. Working through early heat illness symptoms without intervention significantly increases the risk of progressing to heat exhaustion or heat stroke. 

Look Out for Your Coworkers 

Heat illness can impair judgment, which means a person experiencing it may not recognize how serious their condition has become. If you notice a coworker who seems confused, unusually pale, and is either sweating excessively or has stopped sweating in high heat, do not assume they are fine. Alert a supervisor and encourage them to get out of the heat and seek care immediately. Start simple cooling measures including applyting cool packs to the underarms and groin, splashing cool water over skin surfaces and fanning, and if the individual is alert, encourage them to drink cool liquids. 

Know When and Where to Seek Medical Care 

If symptoms do not improve with rest, shade, and hydration within a short period, it is time to seek medical attention. Heat exhaustion that is not properly treated can progress to life threatening heat stroke rapidly. MBI Clinics offers walk-in occupational health care with no appointment needed, ensuring workers across Colorado, Arizona, and Nevada can access prompt evaluation and treatment for mild to moderate heat illness symptoms. Severe symptoms, including altered level of consciousness, require activating emergent care via 911.

An occupational health provider understands the work environment, can assess fitness for duty, communicate work restrictions to employers clearly, and document incidents in a way that supports workers’ compensation and OSHA compliance. After suffering a heat related injury, workers need a structured return to work plan that will decrease the risk of another event occurring after returning to duty.

At MBI Clinics, our providers are trained in workplace injury and illness care. We understand the demands of physically intensive work environments across the industries we serve. For employers, we provide same-day communication on restrictions and return-to-work guidance. For employees, we deliver compassionate, evidence-based care focused on a full recovery. 

Whether your workforce is on a construction site in Phoenix, a warehouse floor in Las Vegas, or an oil and gas facility along Colorado’s Front Range, MBI has locations positioned to support your team. Learn more about our work injury care services and full suite of occupational health services available at our clinics.

Summer does not wait, and neither should your preparation. If your organization wants to strengthen its heat illness prevention program or needs to establish one, contact MBI today to work with our medical exports to design heat safety protocols for your company. With walk-in availability, extended hours, and locations across three states, we are ready to support your workforce when heat illness events occur. 

Find a clinic near you to learn how MBI keeps workforces healthy, compliant, and productive.