1 / 18

Heat Stress from the Sidelines

Heat Stress from the Sidelines. Dan Foster, PhD, ATC August 20, 2009. 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 Unpublished FIU. 2006.

tavon
Download Presentation

Heat Stress from the Sidelines

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  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, VO2 40.1) • HIIS = high • Day 15, On field WBGT 91oF • Tc = 103.6oF • Nausea and dizziness after 1.5 hr Emerson C, et al. Unpublished FIU. 2006.

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

  4. BMI kg/m2 • Normal • 18.5-25 • Overweight • 25-30 • Obese • >30 > Heat production < Heat dissipation low specific heat Gardner J, et al. MSSE 1996; 28:939-944

  5. VO2 ml/kg/min • Acclimation to heat 10-14 days • Poor CV fitness 3 fold increase in risk Davies H. Cross training; 2009 Gardner J, et al. MSSE 1996; 28:939-944

  6. WBGT WBGT = 0.7Twb + 0.2Tbg + 0.1Tdb Reading 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 • <18oC (<65oF) • 18-23oC (65-73oF) • 23-28oC (73-82oF) • >28oC (>82oF)

  7. Mild Heat Illness Symptom Scale 0-10 scale with anchors • 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 Coris E, et al. SMJ; 2006. High-risk positions: OL, DL

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

  9. PARRIS ISLAND MARINE CORPS RECRUIT TRAINING DEPOT, SC

  10. 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 • Hard • <3 • <2 h Adjusted 7-13=extreme risk Hard Work = speed >7 mph, resistance >70% max US Army 2009

  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: • (BWpre – BWpost + 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!

More Related