1. Heat Stress from the Sidelines Dan Foster, PhD, ATC August 20, 2009

2. Case #1 20 yo Div-I FB 6’3” / 274 lbs (BMI 33.5, VO 2 40.1) HIIS = high Day 15, On field WBGT 91 o F T c = 103.6 o F Nausea and dizziness after 1.5 hr Emerson C, et al. Unpublished FIU. 2006.

3. Rested in shade - 101.7 o F Returned to drills and conditioning Progressive dizziness, nausea, disorientation, pallor, transient LOC, sensation of heat – 102.7 o F Ice bags at neck and axilla – 102.7 o F 10 min later could walk Cool water bath (72 o F) In 14 min temp at 100.4 o F

4. BMI Normal –18.5-25 Overweight –25-30 Obese –>30 Gardner J, et al. MSSE 1996; 28:939-944 kg/m 2 > Heat production < Heat dissipation low specific heat

5. VO 2 Acclimation to heat 10-14 days Poor CV fitness 3 fold increase in risk Gardner J, et al. MSSE 1996; 28:939-944 ml/kg/min Davies H. Cross training; 2009

6. WBGT Reading <18 o C (<65 o F) 18-23 o C (65-73 o F) 23-28 o C (73-82 o F) >28 o C (>82 o F) Comments Low risk still exists Level inc as progress through day At-risk should not compete Reschedule, delay, or high alert Roberts W. 1998; Medical Manual. NATA WBGT = 0.7T wb + 0.2T bg + 0.1T db

7. Mild Heat Illness Symptom Scale Feeling tired Cramps Nausea Dizziness Thirst chills Vomiting Confusion Muscle weakness Heat sensations Feeling lightheaded Low-risk positions: QB, P, K Mid-risk positions: DB, RB, LB, R High-risk positions: OL, DL Coris E, et al. SMJ; 2006. 0-10 scale with anchors

8. Exertional Heat Illness Exertional Cases Heat edema/rash Muscle cramps Syncope Exhaustion Stroke Hyponatremia Management Elevation of legs/keep dry Sports drinks, IV Shade, rehydrate Cool, shade, rehydrate Immersion, transport Transport, IV Rectal temp*Return is possible for the first 4, and gradual for last 2

9. PARRIS ISLAND MARINE CORPS RECRUIT TRAINING DEPOT, SC

11. Volleyball Pre-season 2009

12. Should we develop a formal index for risk? Risk Factors –High fat –Low fitness –Past Hx –Not acclimatized –Dehydration –Meds/Supplem* –Heavy clothing –Fever or illness –Sunburn/skin –Prepubescent –Over-exertion –Stoic –CV disease –Sickle-cell trait Antihistamines Antipsychotic Antidepressant Diuretics Ergogenic stimulants betablockers Previous day WBGT Dark colored clothing

13. Risk Assessment Matrix WBGT # days Cat 5 Past work load Work load today Acclimatization d Rest in past day Category 4-5 >4 Hard <3 <2 h 7-13=extreme risk Hard Work = speed >7 mph, resistance >70% max US Army 2009 Adjusted

14. Matrix Actions Know the players –Individual risk factors Check hydration status –Do after each practice –Require extra fluids as needed –Check urine color Check illness and Meds

15. Should ATs be trained in IV administration? Heat cramps Heat syncope Exercise exhaustion Exertional hyponatremia Emerson C, et al. Unpublished FIU; 2006.

16. Is rectal temp necessary? Oral Tympanic Axillary Skin Casa D. JAT. 2007; 42:333-342

17. How far should we go to measure sweat rate? NATA recommends calculating sweat rate on each athlete: –(BW pre – BW post + fluid in – urine vol)/ex time) –Do this for a variety of environmental conditions, practices, competition –95% CI reported 0.5-2.5 L/h Casa D, et al. JAT. 2008; 42:333-342

18. Thanks!