What is heat stress?

Safety takes many forms. Shielding from particulate, detection of noxious gases, and shielding from debris among others. Often left out is one of the most widespread and pervasive dangers – heat stress. Although heat stress is not a danger on every worksite, it is on a great many. Any job in the sun, many in confined spaces, or indoors around heavy equipment, may pose a heat stress danger which can lead to ailments such as heat cramps, heat exhaustion, heatstroke, and perhaps death.

Heat sickness can take many distinct forms, of various levels of severity. Excessive sweating causing skin irritation will cause the mildest form of heat sickness, heat rash. You can treat heat rash by keeping the troubled area completely dry. When the muscles deplete their electrolytes you can develop heat cramps. Heat syncope, which is characterized by dizziness, light-headedness, and maybe fainting, is brought on by dehydration. Although typically not serious, heat cramps have the potential to be life-threatening in those who have heart problems or are on a low sodium diet. On the more severe side are heat exhaustion and heat stroke. If you find yourself in either situation you should seek medical care promptly. Heat exhaustion is most common in the elderly or those with high blood pressure. It is identified by nausea, headaches, dizziness, general weakness, heavy breathing, and irritability as well as an increased body temperature. Heat stroke is the gravest illness caused by heat stress and can cause confusion, seizures, loss of consciousness, and if left untreated, death.

What conditions are most likely to cause heat stress? What can I do to prevent it? The two factors most people know about are environment and hydration. This means keeping cool by drinking plenty of fluids, wearing proper clothing, and staying out of the sun when possible. It also means shunning carbonated or brewed drinks like coffee. Over time all people will acclimate to hot temperatures and this affects the amount of work you can do before you need to rest. It is based solely on background and your body’s capacity to adapt to certain conditions. Because of this there may be laws or guidelines which require a certain amount of rest for a given amount of work at a specified heat level. The only way to acclimate is through increased experience. Other factors exist, such as your health, prior heat stress, age, and recent drug or alcohol usage. You should take all these factors in to account when looking to prevent heat stress from turning in to heat exhaustion.

In order to better track the heat, the humidity, and the dangers related to heat stress TSI manufactures a series of Heat Stress Monitors. Heat is monitored using a series of sensors. Depending on the model of monitor these sensors could include a dry bulb thermometer, a wet-bulb thermometer, a black-globe sensor. The dry bulb thermometer is a sensor isolated from moisture and radiation. It is the same type of device used in homes and workplaces to measure temperature. A wet-bulb thermometer uses a water-soaked cloth to measure humidity. At 100% humidity, the wet-bulb thermometer will read the same as the dry bulb thermometer. As humidity goes down so does the temperature. The black-globe sensor is used to measure a weighted mean temperature of surrounding objects – or the mean radiant temperature. In addition to monitoring the heat, this data is recorded. Using the recorded data, the amount of heat stress workers undergo can be measured and quantified, preventing anyone from overexerting themselves in the heat.

If someone is showing signs of heat stress, they should stop any work they are doing, find a cool place to rest, and drink plenty of fluids. Sports drinks are best if they are available, as they have electrolytes. When someone shows symptoms of heat exhaustion you should take them to see a doctor as soon as possible. But if someone has heat stroke it means their body is no longer able to balance their core temperature. You should call 911 right away, as lasting damage can happen in as little as half an hour. While waiting for emergency services to arrive you should work to cool the body as much as possible. Remove any excess gear, douse them in ice water and apply wet towels to the body.