Beat the Heat, Prevent Exhaustion and Stroke

Beat the Heat, Prevent Exhaustion and Stroke

Hard-working Nebraskans need to heed the perils of summer heat. Preventative measures are all in a day’s work, which could otherwise lead to exhaustion or stroke.

US Department of Labor statistics for 2017-2018 show 40 heat-related deaths. Fatalities nationwide included landscapers, roofers, vegetable harvesters, and a host of other laborers; last year Nebraska had one heat fatality in a detasseling field.

A man wearing light-colored clothing standing with a water bottle in the shade of a tree
Figure 1. When working in the heat, follow these tips: Take frequent breaks and rest in the shade. Wear a wide-brimmed hat, light colored clothing, sunscreen, and sunglasses. Drink water every 15 minutes, or about four cups of water per hour when the heat index is moderate. (PSEP Photo)

Knowing the signs of heat-related illness can be a lifesaver. Do you know the danger threshold when it comes to outdoor heat? Do you know why certain recommendations are in place?

Be informed to prevent yourself, your family, coworkers, and employees from heat cramping, exhaustion, and stroke. The OSHA Quick Card, Protecting Workers from Heat Stress, has valuable information.

Body Overheating

When working in a hot environment, the body must get rid of excess heat to maintain a stable internal temperature. It does this mainly through circulating blood to the skin and through sweating.

When air temperature is close to or warmer than normal body temperature, cooling of the body becomes more difficult. Blood circulated to the skin cannot lose its heat; sweating then becomes the main way the body cools off. Sweating is effective only if the humidity level is low enough to allow evaporation, and if lost fluids and salts are adequately replaced.

A body that cannot get rid of excess heat will store it. Then the core body temperature rises, and the heart rate increases. As the body continues to store heat, the person begins to lose concentration and has difficulty focusing on a task, may become irritable or sick, and often loses the desire to drink. The next stage is most often fainting and even death if the person is not cooled.

Excessive exposure to heat can cause a range of heat-related illnesses, from heat rash and heat cramps to heat exhaustion and heat stroke. Heat stroke requires immediate medical attention because it can result in death.

Exposure to heat can also increase the risk of injuries because of sweaty palms, fogged-up safety glasses, dizziness, and burns from hot surfaces or steam.

Heat Index

Heat IndexRisk LevelProtective Measures
Less than 91°F Lower (Caution) Basic heat safety and planning
91°F to 103°F Moderate Implement precautions and heighten awareness
103°F to 115°F High Additional precautions to protect workers
Greater than 115°F Very High to Extreme Triggers even more aggressive protective measures

Source: US Department of Labor Occupational Safety and Health Administration

The danger of heat is higher when combined with humidity (generally relative humidity of 40% or more); this threat level is measured by the heat index. The higher the heat index, the hotter the weather feels, and the less sweat can evaporate and cool the skin.

Working in direct sunlight can add up to 15 degrees to the heat index. Moderate heat-related health risk occurs any time the heat index is at least 91-103°F. Workers new to outdoor jobs generally are most at risk for heat-related illnesses, notes information from the Occupational Safety and Health Administration (OSHA). It is important to gradually increase the workload or allow more frequent breaks to help new workers acclimate to hot conditions.

Preventative Measures in the Heat

Heat stroke occurs when the body loses its ability to regulate temperature, which may reach 104°F or more. Wear sunscreen to avoid sunburn; sunburn reduces the skin's ability to release excess heat so it becomes more susceptible to heat-related illness.

Anyone working in the heat should drink water every 15 minutes, even if not thirsty. A rule of thumb is to drink about four cups of water per hour when the heat index is moderate. Water temperature should be 50-60°F. While flavored water is OK, avoid beverages that dehydrate such as sugary sodas, caffeinated drinks, and alcohol.

Follow these suggestions, compiled from OSHA and AgriSafe:

  • Take breaks frequently and rest in shade to cool down, especially if there is no air movement.
  • Wear a wide-brimmed hat, light-colored clothing, and sunglasses.
  • Apply sunscreen every hour if skin is sweating.
  • Learn the signs of heat illness and what to do in an emergency.
  • Keep an eye on fellow workers.
  • Ease into the first few days of working in the heat. Your body needs to get used to it.

Symptoms and Care for Heat Exhaustion and Heat Stroke

Symptoms of Heat Exhaustion

  • Skin that is pale, flushed, cool, and/or clammy
  • Headaches
  • Abdominal cramping, nausea
  • Weakness, lethargy, confusion
  • Elevated body temperature

Symptoms of the More Serious Heat Stroke

  • Skin is hot, dry; sweating may be absent
  • Body temperature is 104°F or more
  • Rapid heart rate
  • Chills
  • Confusion, dizziness, possible seizures
  • Possible slurred speech
  • May lose consciousness

Immediate Care for Heat Exhaustion/Heat Stroke

  • Move to a cool, shady area
  • Remove restrictive clothing
  • Cool the body with wet towels or compresses
  • Fan the person
  • Do not leave the person alone
  • Heat stroke is fatal if not treated immediately — call 911 or other emergency number

Site- and Time-Specific Heat Indices

Several digital tools can help you staying informed and safe from the heat. The National Institute for Occupational Safety and Health (NIOSH) offers Heat Safety apps for mobile phones:

The National Weather Service also offers heat index information by the hour for specific sites. Check this “how-to” guide for accessing the data.

Worker Protection Standards

Where pesticides are concerned, employers must keep employees safe as required by the federal Worker Protection Standard. When a WPS-labeled pesticide product requires the use of personal protective equipment for a handler activity (mixing, loading, application, etc.), appropriate measures must be taken to prevent heat-related illness. This may include knowing the heat and humidity of work conditions, altering time of work hours to avoid or limit working in the hottest/most humid situations, providing adequate water breaks and cool-down periods, allowing removal of PPE when not required, etc.

In addition to providing drinking water, ensure that clean water is available for decontamination if a product gets into eyes or on the body.


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