Heat Intolerance Heat Intolerance ProblemsProblems

Kambiz Behzadi, M.D.Kambiz Behzadi, M.D.

Orthopaedic SurgeonOrthopaedic Surgeon

Fremont/PleasantonFremont/Pleasanton

What Causes Heat Related Illness?What Causes Heat Related Illness?

Body’s failure to keep itself coolBody’s failure to keep itself cool Sweat/Evaporation releases heatSweat/Evaporation releases heat Humidity impairs release of heatHumidity impairs release of heat Increased body temperatureIncreased body temperature Heat IllnessHeat Illness

Heat IntoleranceHeat Intolerance

> 300 people die of heat related > 300 people die of heat related illness in U.S.illness in U.S.

Heightened awareness in athletesHeightened awareness in athletes Identify athletes at riskIdentify athletes at risk Not a diseaseNot a disease Accident waiting to happenAccident waiting to happen

Heat IntoleranceHeat Intolerance

Heat Stroke can occur in best Heat Stroke can occur in best athletesathletes

Korey Stringer, Vikings, professionalKorey Stringer, Vikings, professional Estrate Autin, Florida, collegeEstrate Autin, Florida, college

Heat IntoleranceHeat Intolerance

Preseason Football, Marathon, SoccerPreseason Football, Marathon, Soccer Mild to FatalMild to Fatal High Temperature + High HumidityHigh Temperature + High Humidity Preventable awareness, Preventable awareness,

recognition, treatmentrecognition, treatment

HypothalamusHypothalamus

Body’s ThermostatBody’s Thermostat As temperature hypothalamus As temperature hypothalamus

responds:responds: 1. Increase 1. Increase blood flow to skinblood flow to skin 2. Increase 2. Increase sweatingsweating

Temperature RegulationTemperature Regulation

Conduction: jumping into the poolConduction: jumping into the pool Convection: standing in front of fanConvection: standing in front of fan Evaporation: water from liquid to gasEvaporation: water from liquid to gas Radiation: electromagnetic heat Radiation: electromagnetic heat

waveswaves

Temperature RegulationTemperature Regulation

ConductionConduction

Temperature RegulationTemperature Regulation

ConvectionConvection

Temperature RegulationTemperature Regulation

Sweating & Sweating & EvaporationEvaporation

Temperature RegulationTemperature Regulation

RadiationRadiation

Sweating/EvaporationSweating/Evaporation

In hot a environment, In hot a environment, EvaporationEvaporation becomes the becomes the Primary sourcePrimary source of of Heat Heat DissipationDissipation

Humidity Humidity decreasesdecreases our ability to our ability to get rid of get rid of HeatHeat

Exercise Work + HeatExercise Work + Heat

Heat increases Heat increases corecore body body temperaturetemperature

Warm blood bathes the Warm blood bathes the hypothalamushypothalamus

Blood diverted from warmBlood diverted from warm core core to to cool cool shellshell (conduction, convection, (conduction, convection, radiation)radiation)

Sweat glands release hypotonic Sweat glands release hypotonic saline solution (sweat) evaporationsaline solution (sweat) evaporation

PhysiologyPhysiology Exercise work + heatExercise work + heat

HypothalamusHypothalamus

Blood Flow SkinBlood Flow Skin

SweatSweat

Hot EnvironmentHot Environment

Sweat/EvaporationSweat/Evaporation

ConductionConduction

ConvectionConvection

Radiation Radiation

Exercise in Heat Two Demands Exercise in Heat Two Demands on Circulatory Systemon Circulatory System

Blood (Nutrients and Oxygen) to Blood (Nutrients and Oxygen) to Working MuscleWorking Muscle

Blood to Skin to Cool BodyBlood to Skin to Cool Body

Heat and ExerciseHeat and Exercise

MuscleMuscle

G.I. Tract KidneyG.I. Tract Kidney

Circulatory SystemCirculatory System

Liver BrainLiver Brain

Skin Skin

Early Heat IntoleranceEarly Heat Intolerance

ShockShock: Weak pulse, low blood : Weak pulse, low blood pressure, dizziness, syncope, pressure, dizziness, syncope, headache, nausea, vomiting, lack of headache, nausea, vomiting, lack of appetite, weaknessappetite, weakness

Temperature below Temperature below 102102 FF or or 39 C39 C

Stressed Out Circulatory SystemStressed Out Circulatory System

Dehydration & Fluid LossDehydration & Fluid Loss

Worsening State of ShockWorsening State of Shock

Heat Stress + ExerciseHeat Stress + Exercise

Overwhelmed Cardiovascular SystemOverwhelmed Cardiovascular System

Heat ExhaustionHeat Exhaustion

Heat StrokeHeat StrokeBreak down cooling mechanism Break down cooling mechanism

Increase core body temperature Increase core body temperature ++ Shock Damage to cells in body Shock Damage to cells in body Multi-system failure Death Multi-system failure Death

Heat Intolerance ProblemsHeat Intolerance Problems

Heat SyncopeHeat Syncope Heat CrampsHeat Cramps Heat ExhaustionHeat Exhaustion Heat StrokeHeat Stroke

Heat SyncopeHeat Syncope

Athlete stands still after exerciseAthlete stands still after exercise Pooling of blood in extremitiesPooling of blood in extremities Light-headed, dizzy, faintLight-headed, dizzy, faint Core body temperature is normalCore body temperature is normal Lie on ground, shaded area, legs Lie on ground, shaded area, legs

elevatedelevated Oral fluids usually not requiredOral fluids usually not required Recovery rapidRecovery rapid

Heat Syncope TreatmentHeat Syncope Treatment

Heat CrampsHeat Cramps

Painful contractions large muscle groups Painful contractions large muscle groups ( legs, abdomen) ( legs, abdomen)

Dehydration & Loss of balance between Dehydration & Loss of balance between saltsalt and and water water in musclein muscle

Treatment: Treatment: 1. Rest and Passive stretch1. Rest and Passive stretch2. Fluid replacement (water, sports drink)2. Fluid replacement (water, sports drink)

Prevention: Adequate hydration Prevention: Adequate hydration beforebefore and and throughoutthroughout exercise exercise

Heat Cramps TreatmentHeat Cramps Treatment

Heat ExhaustionHeat Exhaustion

Most common form of heat Most common form of heat intoleranceintolerance

Fatigue, weakness, sweating, Fatigue, weakness, sweating, nausea, diarrhea, mental status nausea, diarrhea, mental status normal to slightly impairednormal to slightly impaired

Symptoms of mild shockSymptoms of mild shock Temperature < 102 F or 39 CTemperature < 102 F or 39 C

Heat Exhaustion TreatmentHeat Exhaustion Treatment

Lie in cool, shaded areaLie in cool, shaded area Fluid replacementFluid replacement IV FluidsIV Fluids Do not allow return to vigorous Do not allow return to vigorous

activity until activity until normal body weightnormal body weight is is reachedreached

Heat StrokeHeat Stroke

True True Medical EmergencyMedical Emergency Hyperthermia (Temp>105F or >40C)Hyperthermia (Temp>105F or >40C) Failure of Thermoregulatory Failure of Thermoregulatory

MechanismMechanism Central Nervous System DysfunctionCentral Nervous System Dysfunction Second most common cause of death Second most common cause of death

in U.S. athletein U.S. athlete

Animals Built-in Protective Animals Built-in Protective Mechanism Mechanism

Exercise + Heat Mild ShockExercise + Heat Mild Shock

Fluid Loss andFluid Loss and Shock DehydrationShock Dehydration

Overwhelming TemperatureOverwhelming TemperatureHeat regulatoryHeat regulatoryMechanismMechanism Metabolism Metabolism

Diagnosis Heat Stroke: Rectal Diagnosis Heat Stroke: Rectal Temp > 105 FTemp > 105 F

AggressivenessAggressiveness IrritabilityIrritability Emotional Instability and hysteriaEmotional Instability and hysteria ApathyApathy DisorientationDisorientation Unsteady gaitUnsteady gait Hot, dry skinHot, dry skin UnconsciousnessUnconsciousness

Treatment Heat StrokeTreatment Heat Stroke

Call AmbulanceCall Ambulance Remove clothingRemove clothing Immerse in cool/iced water bathImmerse in cool/iced water bath Cover wet sheets and compress+fanCover wet sheets and compress+fan Airway, Oxygen, RehydrationAirway, Oxygen, Rehydration Support Multi-organ failureSupport Multi-organ failure

PreventionPrevention AcclimatizationAcclimatization: body’s adaptation : body’s adaptation

to heat stress, and increased to heat stress, and increased capacity to work in high temperature capacity to work in high temperature and humidityand humidity

7 days to several weeks7 days to several weeks 30 minutes 2 hours30 minutes 2 hours Lower resting body temperatureLower resting body temperature Increased plasma volumeIncreased plasma volume Lower threshold for sweatingLower threshold for sweating

PreventionPrevention

Practice in early morning or late Practice in early morning or late afternoonafternoon

Night games early in seasonNight games early in season Uniforms light weight, porous, light in Uniforms light weight, porous, light in

colorcolor Sleeves short and socks lowSleeves short and socks low Much skin exposed to airMuch skin exposed to air

PreventionPrevention HydrationHydration is key is key Free intake of fluids during gamesFree intake of fluids during games Regular fluid breaks no less than every half hourRegular fluid breaks no less than every half hour 1 pint1 pint (2 cups) for each (2 cups) for each 1 pound1 pound sweat lost sweat lost 10 oz. Every 30 minutes10 oz. Every 30 minutes Only 50% fluid loss made up by thirstOnly 50% fluid loss made up by thirst (encourage (encourage

fluid intake fluid intake betweenbetween and and duringduring sessions) sessions) Events < 90 min, electrolyte replacement usually Events < 90 min, electrolyte replacement usually

unnecessaryunnecessary

PreventionPrevention

Glucose concentration < 5% to 8%Glucose concentration < 5% to 8% Dilute twofoldDilute twofold 10% glucose (soft drinks and juices) 10% glucose (soft drinks and juices)

cause stomach cramps, nausea, cause stomach cramps, nausea, diarrhea, slow gastric emptyingdiarrhea, slow gastric emptying

Fructose (fruits) absorbed slowly and Fructose (fruits) absorbed slowly and causes G.I. distresscauses G.I. distress

PreventionPrevention

Sports drinksSports drinks Replacement glycogen in (muscle Replacement glycogen in (muscle

and liver) in exercise lasting > 90 and liver) in exercise lasting > 90 minutesminutes

Dilute solution Sodium and Glucose Dilute solution Sodium and Glucose increase absorption of water in small increase absorption of water in small intestineintestine

PreventionPrevention Cumulative HypohydrationCumulative Hypohydration Weigh before and after each practiceWeigh before and after each practice No player should be allowed to return No player should be allowed to return

to play until to play until fluid loss is replacedfluid loss is replaced and and normal weight is achievednormal weight is achieved

Electrolyte Make-upElectrolyte Make-up

Goal to replace sweat that has evaporatedGoal to replace sweat that has evaporated Sweat = water + small concentration of Sweat = water + small concentration of

salts and other electrolytessalts and other electrolytes Concept: Sport drink = SweatConcept: Sport drink = Sweat Evaporated sweat replaced before next Evaporated sweat replaced before next

exerciseexercise Normal diet replaces lost electrolytesNormal diet replaces lost electrolytes Electrolytes in drinks increase absorption Electrolytes in drinks increase absorption

of waterof water