Heat stress poses a significant concern in hot working environments. Human beings must regulate their core body temperature within a narrow range, irrespective of the workload or challenging environmental conditions. An elevation of 6.5 degrees Fahrenheit above the normal body temperature can lead to fatal consequences. When exposed to heat, the body's initial response involves sweating and increased blood circulation closer to the skin's surface to facilitate the cooling of the main body temperature.
Extended exposure to heat triggers a physiological adaptation process known as acclimatization. This adjustment may take several weeks to fully manifest, but notable changes begin to occur within a few days of initial exposure. Once acclimatization is accomplished, working in hot conditions leads to an augmented production of a more diluted sweat and reduces the extent of elevation in heart rate and body temperature.
Heat-Related Disorders
Heat stress risk is heightened by high temperatures, high humidity, exposure to sunlight, and engaging in strenuous work. Excessive heat can lead to diminished concentration, fatigue, and irritability among workers, consequently raising the risk of accidents and injuries. Equipping workers with knowledge on how to manage heat stress is crucial for accident prevention and maintaining the well-being and health of employees.
Heat Rash
Heat rash serves as an initial indicator of possible heat stress. It frequently arises in hot and humid environments, where the skin and clothing remain damp due to sweat not evaporating adequately. The condition can manifest as small, localized patches or affect the entire torso. Even after the affected skin heals, it takes around 4 to 6 weeks for sweat production to return to normal. Treating heat rash involves cleansing the affected area and applying gentle lotions. Preventing severe heat rash involves keeping the skin clean and dry for at least 12 hours each day.
Heat Syncope
Heat syncope is identified by feelings of dizziness or fainting when standing still for prolonged periods in hot conditions. Among heat-induced disorders, heat syncope is the least severe. However, its significant concern lies in the potential for individuals to fall or injure themselves, especially when operating machinery.
Heat Cramps
Heat cramps manifest as painful cramps or spasms in the legs, arms, or abdomen. The affected individual is likely to experience heavy sweating. These spasms may occur either during work or in the evening after work. Heat cramps are commonly caused by a temporary imbalance of fluids and salts, particularly during strenuous physical activity in hot environments.
Heat Exhaustion
Heat exhaustion arises due to a decrease in body water content or blood volume. This condition occurs when the amount of water lost through sweating surpasses the volume of water consumed during heat exposure. Victims of heat exhaustion may exhibit a combination of the following signs and symptoms: heavy sweating, clammy, flushed, or pale skin, weakness, dizziness, nausea, rapid and shallow breathing, headache, vomiting, or fainting.
The initial first-aid measures for heat exhaustion include:
- Relocate the affected individuals to a cooler area.
- Have them lie down on their backs with their feet elevated.
- Loosen their clothing and apply cool, moist cloths to their body, or fan them to aid in cooling.
- Offer small sips of salt water (plain water for those with heart or blood pressure issues).
- It is crucial to seek medical assistance if victims faint or experience vomiting.
Heat Stroke
Heat stroke is a life-threatening heat-related condition commonly linked to working in extremely hot and humid conditions. It can lead to coma or even death. The early signs and symptoms of heat stroke include:
- High body temperature of 104½F or higher.
- Hot, dry skin that may appear bluish or red.
- Absence of sweat in 50 to 75 percent of victims.
- Rapid heart rate.
- Dizziness, shivering, nausea, irritability, and severe headache, which may progress to mental confusion, convulsions, and unconsciousness.
If a worker becomes irrational, confused, or collapses on the job, they should be treated as a heat stroke victim, and immediate medical help should be sought. Early recognition of symptoms and prompt emergency treatment are crucial in assisting someone with a heat stroke. While awaiting medical assistance, efforts to cool the victim down should be initiated by following these steps:
- Relocate the victim to a cooler environment and remove their outer clothing.
- Wet the skin with water and vigorously fan them, apply cold packs repeatedly, or immerse the victim in cool (not icy) water if possible.
- If water is unavailable, fanning can still aid in promoting cooling.
Preventing Heat Stress
Acclimatization to heat involves a gradual adaptation process, spanning over a week or sometimes longer. To achieve effective acclimatization, a recommended schedule is followed, limiting occupational heat exposure to one-third of the workday on the first and second days, one-half on the third and fourth days, and two-thirds on the fifth and sixth days. After any extended absence, due to illness or a vacation of one week or more, the acclimatization procedure should be repeated.
Maintaining proper hydration is crucial in hot environments. Relying solely on the sensation of thirst may not ensure adequate hydration. To replace the significant amount of sweat produced (four to eight quarts) in hot conditions, individuals need to consume one-half to one cup of water every 20 minutes during the workday. Water at 55½ degrees F is preferable to ice-cold or warm water.
To further enhance safety and comfort in the heat:
- Limit exposure time by scheduling hot activities during the coolest parts of the day (early morning or late afternoon).
- If possible, increase assistance or use mechanical means to reduce physical strain.
- Utilize natural or mechanical ventilation to enhance air circulation and evaporation (air velocities up to 5 mph promote heat loss).
- Take regular rest breaks in cool environments away from direct sunlight, especially if experiencing extreme heat discomfort.
- Opt for loose-fitting and breathable clothing. In hot environments, wearing less clothing is generally beneficial, except when standing near a radiant heat source, where covering exposed skin can help reduce heat stress.