Heat exhaustion

Source excerpt

# Does everyone react to heat the same way? (cont.) ## What are the illnesses caused by heat exposure? (cont.) Heat cramps are sharp pains in the muscles that may occur alone or in combination with one of the other heat stress disorders. Cramps are caused by a salt imbalance from heavy sweating. Salt can build up in the body if water lost through sweating is not replaced. Inadequate fluid intake often contributes to this problem. The worker should move to a cooler area and hydrate. Heat exhaustion is caused by the loss of body water and salt through excessive sweating. Signs and symptoms of heat exhaustion include: heavy sweating, weakness, dizziness, visual disturbances, intense thirst, nausea, headache, muscle cramps, breathlessness, palpitations, and skin which is pale, cool, and moist. Do not leave the worker alone. Get medical attention, move to a cool area, and have the person drink cool water if they are able. Can lead to heat stroke if left untreated. Heat syncope is heat-induced dizziness and fainting induced by temporarily insufficient flow of blood to the brain while a person is standing. It can also be caused by vigorous physical activity for 2 or more hours before the fainting happens. It occurs mostly among unacclimatized people. It is caused by the loss of body fluids through sweating, and by lowered blood pressure due to pooling of blood in the legs. Recovery is rapid after rest in a cool area. Heat stroke is the most serious type of heat illness. It is a medical emergency. Signs of heat stroke include having a high body temperature (often greater than 40°C) and complete or partial loss of consciousness. There can also be confusion, irrational behaviour, convulsions, and hot, dry skin. Sweating is not a good sign of heat stress as there are two types of heat stroke — non-exertional or "classical" where there is little or no sweating (usually occurs in children, persons who are chronically ill, and the elderly), and "exertional" where the body te…

Source excerpt

# How do I use the heat stress exposure table (Table 1)? (cont.) ## Personal Protection (cont.) Eye protection that absorbs radiation is needed when the work involves very hot objects, such as molten metals and hot ovens. Work that requires the wearing of impermeable clothing presents an add itional heat burden as the clothing reduces the body's ability to dissipate heat. Under such circumstances, it is often necessary to adjust the WBGT value to account for the additional heat burden. <table><tr><th colspan="2">Table 3 Summary of Control Measures</th></tr><tr><td>Methods of Control</td><td>Actions</td></tr><tr><td>Engineering controls</td><td></td></tr><tr><td>Reduce body heat production</td><td>Mechanize or automate tasks.</td></tr><tr><td>Stop exposure to radiated heat from hot objects</td><td>Insulate hot surfaces. Use reflective shields, aprons, and remote controls.</td></tr><tr><td>Reduce convective heat gain</td><td>Lower the air temperature. If the air temperature is below 35°C, increase the airspeed. Increase ventilation. Provide cool observation booths.</td></tr><tr><td>Increase sweat evaporation</td><td>Reduce humidity. Use a fan to increase air speed (movement).</td></tr><tr><td>Clothing</td><td></td></tr><tr><td></td><td>Wear loose clothing that permits sweat evaporation but stops radiant heat. Use cooled protective clothing for extreme conditions.</td></tr><tr><td>Administrative controls</td><td></td></tr><tr><td>Acclimatization</td><td>Allow sufficient acclimatization period before full workload.</td></tr><tr><td>Duration of work</td><td>Shorten exposure time and use frequent rest breaks.</td></tr><tr><td>Rest area</td><td>Provide cool (air-conditioned) rest areas.</td></tr><tr><td>Water</td><td>Provide cool drinking water.</td></tr><tr><td>Pace of Work</td><td>If practical, allow workers to set their own pace of work.</td></tr><tr><td>First aid and medical care</td><td>Develop and implement emergency procedures. Assign one person trained in first…

Source excerpt

# Does everyone react to heat the same way? No. The risk of heat-related illness varies from person to person. A person's general health influences how well the person adapts to heat (and cold). Those with extra weight often have trouble in hot situations as the body has difficulty maintaining a good heat balance. Age (particularly for people about 45 years and older), poor general health, and a low level of fitness will also make people more susceptible to feeling the extremes of heat. Medical conditions can also increase how susceptible the body is. People with heart disease, high blood pressure, respiratory disease and uncontrolled diabetes may need to take special precautions. In addition, people with skin diseases and rashes may be more susceptible to heat. Other factors include circulatory system capacity, sweat production and the ability to regulate electrolyte balance. Substances -- both prescription or otherwise -- can also have an impact on how people react to heat. The National Institute for Occupational Safety and Health (NIOSH) reports that several studies comparing the heat tolerances of men and women have concluded that women are less heat tolerant than men. While this difference seems to diminish when such comparisons take into account cardiovascular fitness, body size, and acclimatization, women tend to have a lower sweat rate than men of equal fitness, size and acclimatization. This lower sweat rate means that there can be an increase in body temperature. ## Should workers be trained to recognize the symptoms of heat illness? Yes. Workers should be trained to recognize the signs and symptoms of heat-related illnesses. If possible, start a "buddy system" because sometimes it is hard for workers to notice their own symptoms. ## What are the illnesses caused by heat exposure? Heat exposure causes the following illnesses: Heat edema is swelling that generally occurs among people who are not acclimatized to working in hot conditions. The swell…

Source excerpt

# Can we become acclimatized to hot environments? The body adapts to a new thermal environment by a process called acclimatization. Complete heat acclimatization generally takes six to seven days, but some individuals may need longer. Loss of acclimatization occurs gradually when a person is moved permanently away from a hot environment. However, a decrease in heat tolerance can occur even after a few days away from work. Therefore, it is not advisable for anyone to assume a full workload under very hot conditions on the first day of their return to work. New and returning employees should acclimatize before assuming a full workload. It is advisable to assign about half of the normal workload on the first day of work and gradually increase it over the subsequent days. Although well-trained, physically fit workers tolerate heat better than people in poor physical condition, fitness and training are not substitutes for acclimatization. Some medications interfere with acclimatization. For example, hypotensives (drugs causing low blood pressure), diuretics, antispasmodics, sedatives, tranquilizers, antidepressants and amphetamines decrease the body's ability to cope with heat. Workers should seek a doctor's advice on the suitability of a medication for them if they work in hot environments. Consumption of alcohol also interferes with acclimatization. ## How can I prevent heat-related illnesses? If practical, workers in hot environments should be encouraged to set their own work and rest schedules based on industry standards such as the ACGIH Screening Criteria in Table 1. Infrequent or irregular tasks , such as emergency repairs of hot process equipment, often result in heat exposure. Experienced workers can often judge heat strain and limit their exposure accordingly. Inexperienced workers may need special attention as they may continue to work beyond the point at which signs of heat strain appear. People are generally unable to notice their own heat stress-rela…

Source excerpt

# Does everyone react to heat the same way? (cont.) ## What are the symptoms and first aid steps for heat exhaustion? (cont.) - Thirst. - Heavy sweating. - High body temperature. First aid for heat exhaustion includes: - Get medical aid. Stay with the person until help arrives. - Move to a cooler, shaded location. - Remove as many clothes as possible (including socks and shoes). - Apply cool, wet cloths or ice to the head, face or neck. Spray with cool water. - Encourage the person to drink water, clear juice, or a sports drink. ## What are the symptoms and first aid steps for heat stroke? Heat exhaustion may quickly develop into heat stroke. Symptoms of heat stroke include: - Hot, dry skin or profuse sweating. - Confusion. - Loss of consciousness. - Seizures. - Very high body temperature. First aid for heat stroke includes: - Call 911 immediately. Heat stroke is a medical emergency. - Stay with the person until help arrives. - Move to a cooler, shaded location. - Remove as many clothes as possible (including socks and shoes). - Wet the person's skin and clothing with cool water. - Apply cold, wet cloths or ice to the head, face, neck, armpits, and groin. - Do not try to force the person to drink liquids. What are the illnesses caused by long-term (chronic) heat exposure? Hot Environments - Health Effects and First Aid CCOHS