Environmental Concerns

1. Environmental Concerns Extreme Environmental Conditions

2. Exertional Heat Illness (EHI) • Exercise in a hot, humid environment • Protective gear may limit heat dissipation • May lead to: • dehydration • heat cramps • heat exhaustion • heat stroke • Heat illness is largely preventable • 2003 is the 1st year of new NCAA 2 a day practice schedule!

3. Issues That Cause Injury • Exertional Heat Injuries (EHI) • Stress to the thermoregulatory system • Fluid loss • Electrolyte imbalance • Acclimatization • Gender • Age

4. Heat Transfer • What happens with exercise? • Efficiency: work efficiency vs. heat production • Heat production vs. heat loss • Status of core temperature • Heat transfer • Evaporation – sweating mechnism • Radiation – skin temperature • Convection – diversion of heat from blood to surrounding tissue • Conduction – heat transfer from one tissue to another (muscle to blood vessels)

5. How the Body Works • When temperature is below 680 F • Radiation and convection works very efficiently • When temperature is above 680 F • Evaporation is main method to dissipate heat in addition to radiation and convection • When temperature is above 950 F • Convection and radiation stop working

6. Other Factors Effecting Heat Stress • Ambient air temperature • Radiant heat • Humidity • Wind speed

7. EHI Definitions • Heat Cramps – condition that presents during or after intense exercise as an acute, painful, involuntary muscle contraction • Heat Syncope – orthostatic dizziness accompanied with a brief episode of fainting • Heat Exhaustion – inability to continue exercise associated with heavy sweating, dehydration, Na loss, and energy depletion • Exertional Heat Stroke – elevated core temp >400C associated with signs of organ system failure due to hyperthermia • Exertional Hyponatremia – serum-sodium levels less than 130mmol/L

8. Monitoring Environmental Conditions • Sling psychrometer • Heat stress monitor • WBGT Index monitor • What does the literature say?

9. Initial Research • Yaglou & Minard, 1957 • Define conditions under which heat injury may occur • Used military personnel • Effective Temperature (ET) index • Air temp, humidity, & wind • Effective Temperature Radiation (ETR) • included radiation • WBGT Index

10. Historical Perspectives • Department of Defense Heat Stress Index(1980) • Less conservative, used for Marine Corps Parris Island Training Complex • ACSM Heat Stress Index (1975,1987,1996) • Heat and Cold Illnesses During Distance Running (Position Statement) • 1996 Atlanta Olympic Games (DE Martin) • Endurance Events: heat stress measurements were consistently “moderate to high” • 4551 Athletes/179 Heat-related injuries • 3.93 EHI/100 Athletes

11. WBGT IndexRegression Equation WBGT = 0.7Twb + 0.2Tbg + 0.1Tdb Yaglou & Minard, Arch Ind Health, 1957

12. ACSM WBGT Index Risk Chart WBGT FLAG RISK COMMENTS <180 C Green Low low risk is present based on gender, age, body wt, etc. 18-230 C Yellow Mod risk inc. as event progresses through day 23-280 C Red High aware of injury potential; at risk individuals should not compete >280 C Black Extreme consider rescheduling or delay event, if continuing be on high alert

13. DOD WBGT Index Risk Chart WBGT FLAG RISK COMMENTS 26.7-29.40 C Green Low Exercise with caution 29.5-310 C Yellow Mod Strenuous exercise suspended for 1st phase recruits 31.1-32.20 CRed High Strenuous activities suspended for all recruits >32.20 C Black Extreme All activities suspended

14. Prevention Techniques • Acclimatization: 10 – 14 days • Proper hydration practices • Monitor weight • Identify high-risk athletes • Schedule practice at cool part of the day • Clothing • Diet/nutrition • NCAA rules on FB practice

15. Common Strategies • Pre-event hydration • Water vs. sports drinks • Hydration during activity • Post-exercise hydration • Should thirst be your guide? • Educate – coaches, parents, athletes

16. Who is at Risk • Anyone dehydrated • Obese or heavily muscled • Young children • Anyone who has had a previous EHI

17. Injuries In The Cold • How do we stay warm? • Layering of clothes • Physiologically? • BMR • Increase muscle activity • Shivering

18. Hypothermia • Core temperature below 950 F • 93-95 degrees: shivering, numbness, loss of muscular coordination • < 910 muscular rigidity, LOC • Physiological Changes • Skin hardens • Loss of circulation in extremities

19. Treatment Strategies • Prevent further heat loss • Do not attempt to warm the body • Implement EAP – 911 • Physiological changes • Pulse may be undetectable • Maintain airway • NO CPR – inability to compress chest • Death not certain until – WARM & No Pulse

20. Frostnip/Frostbite • Frostnip – involves only superficial epithelial layers • Burning sensation of extremities • Skin is pale • Slow warming • Frostbite • Ears, nose, fingers, toes • Superficial & Deep tissues affected • Medical emergency – do not attempt to re-warm

21. Prevention Strategies • Proper nutrition • Muscular activity • Decrease heat loss • Layer clothing – avoid cotton • Keep sweat away from skin • Keep head covered, face & hands • Proper footware – allow for air to circulate

22. Acclimatization • Must be gradual over 10 – 14 days • Gradual increase with intensity • Gradual change with equipment • Proper hydration • Maintain electrolytes • Monitor weight

23. Lightning Safety • Recommendations – pg. 255 • Flash-to-Bang Method • Tracking weather • Early detection devices