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Ohio State University Extension


Be Aware of Heat Stress

Small Farm and Gardening Safety and Health Series
Agriculture and Natural Resources
S. Dee Jepsen, Associate Professor and State Safety Leader, Agricultural Safety and Health, Food, Agricultural and Biological Engineering
Jeffery Suchy, Graduate Student and Lecturer, Food, Agricultural and Biological Engineering

Farming and gardening activities involve working outside during the hot summer months. Hard work and warm temperatures can lead to dangerous health conditions. Heat stress is a rise in body temperature due to muscle exertion or a warm working environment. Heat exhaustion and heat stroke occur when the body is unable to cool and maintain a normal body temperature. As the body temperature increases, the heart rate and the blood pressure also rise. These conditions pose an even greater risk for individuals with existing heart conditions, high blood pressure and obesity. A body temperature increase of just 2 degrees Fahrenheit can affect mental functioning, and a 5-degree increase can result in serious illness or death.

During hot weather, heat stress may be an underlying cause of other conditions, including heart attack. Incidents that are seemingly unrelated, such as falls and equipment-related injuries, may occur more frequently in hot weather due to fatigue and discomfort.

Heat Exhaustion Symptoms and First Aid

Heat exhaustion may occur after several days of heat exposure without enough fluid replacement. Symptoms of heat exhaustion include:
• Below normal body temperature.
• Moist, clammy skin.
• Weakness and muscle cramps.
• Headache.
• Dizziness, nausea or vomiting.
• Fainting.
First aid treatment for heat exhaustion includes:
• Moving the victim to a cool place.
• Letting the victim rest, lying down with legs elevated 8 to 12 inches.
• Applying cold packs or wet towels and fan the victim.
• Giving the victim cold water (if conscious).
• Seeking medical attention after 30 minutes if the victim has not improved.

Heat Stroke

The most serious heat-related illness is heat stroke. Side effects of heat stroke can be as mild as heat sensitivity and as severe as brain or kidney damage, coma and death. All age groups are at risk for heat stroke if the working or living environment is too warm. However, children and the elderly are more susceptible to heat stroke than adults. Symptoms of heat stroke include:
• High body temperature.
• Hot, dry skin (not sweaty). Red, flushed appearance.
• Rapid pulse and difficulty breathing.
• Confusion, hallucinations or irrational behavior.
• Agitation, convulsions or seizure.
First aid treatment for heat stroke includes:
• Calling for medical help. All heat stroke victims need hospitalization.
• Moving the victim to a cool place and removing heavy clothing.
• Keeping the victim’s head and shoulders slightly elevated.
• Cooling the victim immediately by any available means:
◦ Applying ice packs to armpits, neck and groin.
◦ Putting the victim in a cool shower or bath.
◦ Applying cool, wet cloths to the victim.
• Preventing hyperthermia by cooling the victim until his/her body temperature drops to 102 degrees Fahrenheit.
• Watching and caring for seizures.
• Not administering aspirin or acetaminophen (Tylenol) to the victim.

Heat Stress Prevention Techniques

Hydrate to help avoid
heat stress.

Recognizing and preventing heat stress is important. Worker safety can be increased by reducing worker impairment and fatigue, which can contribute to injuries. Early recognition allows for treatment before life-threatening conditions occur. Because people work slower and less efficiently when they are suffering from heat stress, increased productivity can be gained.

• If hot weather work/activities are anticipated, start drinking extra water the day before. Urination should be frequent (two to three times per hour) and look white (clear) if properly hydrated.
• Allow for a 10- to 15-minute break every two hours, and drink one liter of water every one to two hours. If possible, carry water to the work area to help prevent dehydration.
Adapt working schedules to the weather:
• Avoid working outside during the hottest parts of the day. Consider moving work times for outdoor activities to mornings and evenings during the hottest months of the year. This will increase efficiency and help prevent chronic dehydration, sunburn and high body temperatures.
Build up a tolerance for working in the heat:
• Heat tolerance is normally built up over a period of one to two weeks. Help workers transition during the spring and early summer by initially scheduling shorter periods of work outside.
Avoid substance abuse and some medications:
• Alcohol and drugs can increase the effects of heat stress due to dehydration, increased pulse and other drug-induced side effects.
• Read medication labels carefully and ask a pharmacist or doctor if the medications will increase sensitivity to sun or heat. Some antibiotics may induce sun sensitivity and cause patients to sunburn very easily.


• Agricultural Tailgate Safety Training: Heat Stress. Columbus, OH: Ohio State University Extension, n.d.

Reviewer: Kent McGuire, CFAES Safety and Health Coordinator, Food, Agricultural and Biological Engineering
Originally posted Nov 12, 2015.