Heat & Cold Stress

1. Heat & Cold Stress

2. This material was produced under grant number 46B4-HT15 from the Occupational Safety and Health Administration, U.S. Department of Labor. It does not necessarily reflect the views or policies of the U.S. Department of Labor, nor does mention of trade names, commercial products, or organizations imply endorsement by the U.S. Government.

3. Heat & Cold StressHEAT • INTRODUCTION • Since 1936, according to the National Safety Council, 30,000 people have died from heat related illnesses. • On the average, 384 people die each year from heat stroke. • Heat related injuries seem to occur often with the elderly,  people who are not in good  physical condition, or those who are not acclimatized to the heat.

4. Heat & Cold StressSTRESS • Relative to workload, health and physical factors, metabolism, type of clothing, direct contact, prior injury or predisposition. • Control is related to reducing stress. • Susceptibility varies

5. Heat & Cold StressSources of Heat: • Metabolic (Internal) • Environmental (External) • Body Maintains balance by sweating: H + E = M +/- R +/- C

6. Heat & Cold StressHot Environments • Heat Disorders • Heat fatigue: stress from lack of acclimatization • Heat stress/ cramps: electrolyte balance • Heat strain/exhaustion: headache, nausea, weakness, etc. • Heat stroke: temp regulation failure (temp gets to above 41°C (105.8°F)) • Ranges from elevated temperature to syncope (fainting) to complex heat stroke

7. Heat & Cold StressTreatment • Remove to cool area, and remove outer clothing, wet skin and ventilate for evaporative cooling. If heat stroke evident, professional measures must be taken to rapidly bring down body temp.

8. Heat & Cold Stress Preventing Heat-Related Health Problems • Acclimation - accustom yourself to the weather prior to long durations of physical activity. • Maintain Body Fluids - Fluid intake must be maintained throughout the course of physical activity. • Do not rely on thirst as an indicator of dehydration because your body loses water faster than you realize. • Alcohol should be avoided because it is a diuretic, which increases dehydration and can interfere with heat loss.

9. Heat & Cold Stress Preventing Heat-Related Health Problems (cont’d) • Proper Diet – Eat light and stay away from heavy foods. They increase metabolic heat production and also increase water loss. Eat smaller, well-balanced meals more often. • Rest Periods – Pace your work activities at a slower rate during high temperatures, take frequent rest periods in a shaded area, and drink plenty of fluids.

10. Heat & Cold StressPreventing Heat-Related Health Problems (cont’d) • Dress Light – Lightweight, light-colored clothing reflects heat and sunlight and helps your body maintain normal temperatures. • Wear loose-fitting clothes such as cotton, which lets air move over your body. • Wide brimmed hats should also be worn.

11. HOW HOT IS IT?

12. ACGIH Guidelines • Workers should rest when deep body temp reaches 38°C (100.4°F).

14. SUGGESTEDHEAT WORK PROCEDURES

15. Heat & Cold Stress Control of Heat Stress • Acclimatization • Breaks • Ventilation • Auxiliary Control • Cooling • Drinks • Clothes

16. Heat & Cold StressCold Stress • Reaction by: • Constriction of blood vessels • Shivering • Glucose production

17. Heat & Cold StressCold Stress Disorders: • Hypothermia - slows down reactions, speech, etc. • Watch sedatives • Blood vessel abnormalities • Raynaud’s phenomenon • Acrocyanosis • Thromboangiities Obliterans • Frostbite

18. Wind-chill • Calculation of wind speed, (humidity &) temperature

19. Heat & Cold Stress Prevention • Acclimatization • Dehydration • Electrolytes (Salt) • Control measures - shielding • Personal Protective Equipment