1. HEAT STRESS

2. Prepared by Paul Young 2 Heat Sources Temperature Humidity Radiant Heat Air Velocity All of these have an effect on the human body and the amount of stress that is imposed.

3. Prepared by Paul Young 3 Skin Temperature The body reacts to external temperature by circulating blood to the skin. This increases epidermal temperature and allows the body to give off excess heat through the skin. If the muscles are being used for physical labor, less blood is available to flow to the skin and give off heat.

4. Prepared by Paul Young 4 Perspiration “Men sweat, women perspire, ladies merely glow,” or so said a southern belle in a time of extreme stress. Sweating is another mechanism the body uses to regulate internal temperature. This is effective only if the humidity level is low enough to permit evaporation, and if lost fluids and salts are replaced properly.

5. Prepared by Paul Young 5 Effects of heat If the body cannot shed excess heat, it stores the heat internally. As the body’s core temperature rises, there is an increase in heart rate and other effects may occur, depending on temperature, physical activity rate, humidity, etc. As core temperature increases, individuals may experience: Lost concentration Difficulty focusing on tasks Irritability Sickness, vomiting Loss of desire to drink fluids Fainting Unconsciousness Death

6. Prepared by Paul Young 6 HEAT INDEX

7. Prepared by Paul Young 7 Calculating Heat Index Check the weather forecast: Find today’s forecast high temperature Find today’s expected humidity. On the chart: Temperature is across the top of the chart Humidity is down the left side. Cross the two values to find today’s apparent temperature. Remember that these values are for shaded areas with light wind conditions. Exposure to full sun will typically increase these values by 15°. Working on hot asphalt will also add 10°. Strong winds, especially hot, dry winds, also increase hazards because of the drying effect on the skin.

8. Prepared by Paul Young 8 Dangers related to heat stress Heat Index 105 to 129 degrees Sun stroke, heat cramps and heat exhaustion are all likely. Heat stroke is possible with prolonged exposure and physical activity. Heat Index 130 and above Heat stroke is imminent. Heat Index 90 to 100 degrees: Sun stroke, heat cramps and heat exhaustion are all possible with prolonged exposure and physical activity.

9. Prepared by Paul Young 9 Heat Exhaustion Symptoms: Headaches; dizziness; weakness; mood changes; upset stomach; vomiting; fainting; pale, clammy skin. What to do: Act immediately. If not treated, heat exhaustion can quickly become heat stroke. Move the victim to a cool, shaded area. Don’t leave the victim alone. If symptoms include dizziness or lightheadedness, lay the victim on his or her back and raise the feet 6 to 8 inches. If symptoms include nausea, lay the victim on his or her side. Loosen or remove heavy clothing. Have the victim drink a cup of cool water every 15 minutes. Cool the victim by fanning or spraying If the there are no signs of recovery after 15 minutes, call 911.

10. Prepared by Paul Young 10 Heat Stroke What to do: Call 911 immediately. Move the victim to a cool, shaded area and lay the person on his or her back. Loosen and remove any heavy clothing. Have the person drink a cup of cool water every 15 minutes (if conscious). Cool the body by fanning or spraying with a cool water mist, damp cloths or a wet sheet. Place ice packs under the armpits and in the groin. Symptoms: Dry, pale skin with no sweating; hot, red skin that looks sunburned; mood changes; seizures or fits; unconsciousness with no response.

11. Prepared by Paul Young 11 Electrolytes Electrolytes can take two forms: Simple inorganic salts of sodium, magnesium, potassium or calcium. Complex organic molecules. Electrolytes flow through muscle cells to help maintain the normal cell function. Electrolytes are lost through perspiration and urination, and this depletes muscle cells and weakens the muscle tissue.

12. Prepared by Paul Young 12 Fluid intake While it is important to replace body fluids through drinking adequate quantities of cool water, this does not replace those valuable electrolytes. Water is still “nature’s perfect drink”, but studies have shown that electrolyte replacement products are absorbed faster in the first minute after intake. NINETY-EIGHT PERCENT {98%}

13. Prepared by Paul Young 13 Thirst While involved in physical activity, especially as the temperature increases, most people experience the sensation of thirst, and drink water or other fluids to offset this sensation. As heat stress increases, many people lose the sensation of being thirsty, and so they don’t replace the lost fluids, leading to dehydration and the other harmful effects of heat stress.

14. Prepared by Paul Young 14 Types of Fluid Fluids that DON’T help quench thirst Carbonated drinks (soda pop) Caffeinated drinks (soda pop, coffee, tea) Alcoholic drinks (beer, wine) Fluids that help quench thirst: Water Sports drinks like Gatorade Electrolyte replacement drinks

15. Prepared by Paul Young 15 Taste Taste has a marked effect on how employees help prevent dehydration. Not too long ago, employees exposed to high levels of work-related heat were required to drink salted fruit juices and other poor tasting drinks. Modern electrolyte replacement fluids have a taste that many people prefer to water. If people prefer the taste, they will be more likely to drink the fluid.

16. Prepared by Paul Young 16 The Buddy System As in many other work-related hazardous situations, it’s important that we look out for ourselves and each other: Always be aware of your own thirst. Drink when you feel thirsty. Working in direct sun on a hot day, you need about a quart of fluid every hour to replace what you lose through perspiration, etc. Watch your crew mates. If you see any signs of heat stress, encourage the team member to drink water or electrolyte replacement fluids. Notify your crew boss if you see a fellow worker exhibiting signs of heat stress.