(Source: Penn State Ag Safety and Health)
Farmers and ranchers perform job responsibilities in all types of weather conditions including excessive heat and humidity. It is important for agricultural producers to understand risks associated with working in high heat work environments, potential heat-related illnesses, precautionary steps, and appropriate medical responses.
Our body’s primary defense against heat is through sweating. Sweating allows moisture to collect on the skin and evaporate. Sweating happens when the surrounding environment becomes greater than skin temperature. When this occurs, an internal body system called the sympathetic nervous system releases a chemical called acetylcholine which turns on sweat glands in the skin in an area called the dermis. The sweat glands release moisture and move it to the outer surface of the skin for cooling. However, in hot, humid weather, the moisture does not always evaporate and can collect on the skin causing the body to warm up and the heart to pump more blood to the skin. When this happens, the body starts to sweat excessively and depletes the body of water and electrolytes, which can lead to a heat-related illness.
The range for normal body temperature is between 96° to 100°F. Hard exercise, strenuous work, or fever will usually put the body in a range between 101° to 105°F. At 105° to 107°F, cooling treatment or fever therapy may be needed, and at even higher body temperatures, heat exhaustion and heat stroke usually occur. Heat exhaustion and heat stroke indicate a serious impairment to the body's cooling system and is a definite signal for medical assistance. Heat stroke or body temperatures beyond 110°F may result in death.
Everyone is at risk for heat-related illness if they do not follow standard precautionary measures. The following factor(s) can increase the chance for developing one of the five main heat-related illnesses:
There are five heat-related illnesses: heat rash, syncope, cramps, exhaustion, and stroke. Heat exhaustion and heat stroke are typically the most severe and require immediate medical attention. Figure 1 outlines each illness, typical symptoms, and treatment.
|Heat rash||Excessive sweating during humid weather||Red, blotchy skin rash; clusters of pimples or small blisters||Keep the affected area dry, and treat with cornstarch or powder. Work in a cooler, less humid work environment.|
|Heat syncope||Prolonged standing or rising suddenly from a sitting or lying position||Light-headedness, dizziness, or fainting||Move person to a cool place to lie down, elevate the feet, and give liquids to drink.|
|Heat cramps||Loss of body salts and fluids from sweating during strenuous activity||Pain in stomach, arms, and/or legs||Stop activity, drink clear or sports beverage. Massage affected muscles.|
|Heat exhaustion||Excessive loss of body salts and water from sweating||Cool, pale skin, dizziness, headache, cramps, nausea, sweating, weakness, confusion, high body temperature, and unconsciousness||Have the person drink plenty of cool fluids, remove excess clothing, and apply cool compresses. Call for medical attention.|
|Heat stroke||System that regulates body temperature fails and the body temperature rises to critical levels||High temperature, hot dry skin, slurred speech, confusion, loss of consciousness, and seizures||Immediately call for medical assistance. Move the person to a cool place, and slightly elevate the head and shoulders. Remove outer clothing, and cool the body with water, wet towels, or sheets.|
View the Occupational Safety and Health Administration video below to learn about the risk of heat-related illnesses for outdoor workers.
Heat-related illnesses and agricultural producers. (2012) Farm and Ranch eXtension in Safety and Health (FReSH) Community of Practice. Retrieved from http://www.extension.org/pages/62261/heat-related-illnesses-and-agricultural-producers.
Heat stress. (2011). Centers for Disease Control and Prevention. Retrieved from http://www.cdc.gov/niosh/topics/heatstress/.
Jepsen, S.D., McGuire, K. & Poland, D. (2011) Secondary injury prevention: Heat stress. The Ohio State University. Retrieved from http://ohioline.osu.edu/factsheet/AEX-981.4-10.
Murphy, D. & Walker, C. (1994). Heat illness and farm work. Pennsylvania State University College of Agricultural Science Cooperative Extension. Retrieved from http://www.agsafety.psu.edu/factsheets/E38.pdf.
Porth, C.M. (2010). Pathophysiology, 8th ed. Lippincott-Williams.
Protecting workers from the effects of heat. (2011). Occupational Safety and Health Administration Fact Sheet. Retrieved from http://www.osha.gov/OshDoc/data_Hurricane_Facts/heat_stress.pdf.