National Extension Risk Management Education Conference April 17, 2007 -- Phoenix

1. National Extension Risk Management Education Conference April 17, 2007 -- Phoenix

2. National Extension Risk Management Education Conference April 17, 2007 -- Phoenix Education to Help Manage Old and New Risks of Heat Stress on CA & AZ Farms Howard Rosenberg University of California, Berkeley Trent Teegerstrom University of Arizona, Tucson

3. Heat for fun

4. Heat as a Problem

11. Excess Heat Can Harm • Heat stress: An accumulation of heat in the body that raises core temperature and threatens normal functioning. • Heat illness: A breakdown of normal physical or mental functioning that is caused by heat stress directly or by the body’s response to it.

12. Heat "illnesses" • Heat stroke • Heat exhaustion • Heat syncope (fainting) • Heat cramps • Heat rash, other skin ailments • Subtle impairment - physical & mental

13. Heat Illnesses/First Aid Heat rash Regarded as least severe of heat illnesses, occurs when sweat clogs pores.  Though heat rash usually causes only temporary discomfort, it can develop into an infection. Cleanse the affected area thoroughly and dry completely. Calamine or other soothing lotion may help relieve the discomfort. Heat syncope Most likely to affect people who are not acclimatized to working in hot environments.  Syncope generally is the sudden loss of consciousness due to lack of sufficient blood and oxygen to the brain.  Heat stress can cause it by "diverting" blood to the lower body or extremities at the expense of the brain. Rest in shade, drink plenty of water or electrolyte fluids. Heat cramps Often extremely uncomfortable and can be completely disabling.  Heat cramps typically occur during or after hard work and are caused by electrolyte deficiencies that result from extended periods of intense sweating.  Symptoms include painful spasms of leg, arm or abdominal muscles, heavy sweating, and thirst.  Rest, drink plenty of water or electrolyte fluids.

14. More Heat Illnesses/First Aid Heat exhaustion Also occurs during work but results from dehydration, lack of acclimatization, reduction of blood in circulation, strain on circulatory system, and reduced flow of blood to the brain.  Symptoms of heat exhaustion include fatigue, headache, dizziness, muscle weakness, nausea, chills, tingling of hands or feet, confusion, loss of coordination, fainting and collapse.  Rest in the shade or cool place. Drink plenty of water (preferred) or electrolyte fluids.  Heat stroke Can occur suddenly if heat exhaustion is not treated, and it can be fatal.  At this extreme state of heat stress, the body typically has a core temperature exceeding 104 degrees F and can no longer cool itself.  A person suffering heat stroke needs immediate attention and should be taken to a medical facility as soon as possible. A medical emergency! Brain damage and death are possible.Douse the body continuously with a cool liquid and summon medical aid immediately.

15. More Hazards from Heat Besides causing illness, heat stress raises risk of accidents and poor performance. • Physical discomfort • Weakness or cramping • Sweaty, slippery hands • Blurry vision, fogged glasses • Slower mental and physical reactions • Diverted attention, loss of concentration • Lapses in judgment • Irritability and anger • Dizziness, confusion, nausea, fainting

16. Translating into Business Cost$ • poor quality work and decisions • damage to product and equipment • operational disruptions • 1st aid and medical treatment • replacement of disabled workers • increased WC insurance

19. New Rules

20. Gore movie and Fresbee news headline

21. The rest of this hour . . . • Heat stress physiology 101 • The new CA regulation • RME project in California • RME project in Arizona • Lessons and unknowns

22. The rest of this hour . . . • Heat stress physiology 101 • The new CA regulation • RME project in California • RME project in Arizona • Lessons and unknowns

24. Physiology of Heat Stress - 1 During both rest and activity, the human body tries to maintain an internal temperature of 98.6 F.

25. Where does the heat that stresses us come from?

26. Avg Daily High Temps in CA & AZ MayJun Jul Aug Sep Oct Cloverdale 77.5 84.9 90.7 90.0 86.2 77.9 Modesto 81.588.994.1 92.3 87.4 78.3 Watsonville 66.2 67.870.271.273.271.8 Yuma94.2 103.3 106.6105.3 100.5 90.3 Phoenix93.6 103.5 105.9 103.7 98.3 88.1 Bakersfield 84.6 92.3 98.4 96.4 90.0 80.6 El Centro 94.1 104.0 108.0 106.2 101.3 90.0

27. A Very Hot Day?

30. Activities Generate Heat activity kcal/hour

39. Regulation of Body Temperature • Thermal "challenges" • Cold • Heat • Responses and coping adjustments • Behavioral • Autonomic (no thinking)

40. Physiology of Heat Stress - 2 • Activity and outside heat sources raise the body’s core temperature. • Heated blood is pumped to outer layers of body, from which it radiates and conducts to the environment, if cooler. • If heat has to be shed faster, glands produce more sweat that carries it through pores to skin surface, from which it evaporates to accelerate cooling.

41. Physiology of Heat Stress - 3 • The longer a body sweats, the less blood there is to carry excess heat to skin or oxygen and nutrients to muscles. • After 3 hours, a dehydrated worker may experience: • Headaches • Muscle fatigue • Loss of strength • Loss of accuracy and dexterity • Heat cramps • Reduced alertness • Nausea

42. Level Cum. fluid loss % Body wt. Time till* Symptoms and effects Minor dehydration 1.5 lb. (.75 L) 1% 1 hr. Generally not perceived. Incipient stress 3.0 lb. (1.5 L) 2% 2 hrs. Begin thirsty, hot, minor discomfort. Moderate stress 4.0 lb. (2.25 L) 3% 3 hrs. Loss of energy, muscle endurance. High stress 6-9 lb. (3-4 L) 4-6% 4-5 hrs. Impaired coordination, endurance. Low energy, strength. Fatigue, cramps. Very high 9-12 lb. (4-5.5 L) 6-8% 6-7 hrs. Headache, dizziness, nausea, (exhaustion) Serious fatigue. Emergency 11+ lb. (5+ L) 7+% 7+ hrs. High temperature. Confusion. Loss (stroke) of consciousness. * based on a 150 lb. male doing moderately active work in hot weather and not replacing fluids Heat Stress Effects if Fluid not Replaced

43. Environmental and personal factors affect the rates at whichbodies gain and lose heat.

44. General Recap: Physiological Response to Heat • Work activity produces heat • “Core” body temperature rises • Heart rate speeds up and veins dilate • Blood flow carrying heat to skin increases • Sweat glands activate and draw water • Body loses water and salts • Bloodstream volume and service decrease • Functions decline and heat illness may present

46. Recommended Self-care • Learn about recognition, treatment, physiology • Monitor environment and assess own risk • Work easier until "acclimatized" • Try to do heavier jobs in cooler hours • Work in shade if possible; avoid full sun • Wear lightweight clothing and protective gear • Take rest periods or reduce pace • Drink sufficiently and timely to replace lost fluids

47. How Much?

49. Fluid Replenishment Guidelines U.S. Army, NIOSH & other research: • 25 oz./hr. during moderate work at 82-90 deg. • 33 oz./hr. during heavy work at 90+ deg. • Don’t wait for thirst • Rest every hour, a lot • Drinks small amounts frequently (drip, not flood)