Heat Illness & Hydration John Neidecker, DO, ATC Sports Medicine Physician Cooper Bone & Joint Institute.

Heat Illness & Hydration

John Neidecker, DO, ATCSports Medicine Physician

Cooper Bone & Joint Institute

Why do we sweat?

• To cool the body down

• High body temperatures can lead to organ damage

• As muscles contract – heat is produced

How do we sweat?

• Neurological response

• Skin blood vessels vasodialate – stimulating sweat glands

• Sweat evaporates and cools the skin

What does sweat contain?

• Water• Urea• Electrolytes

– Sodium

The composition is highly variable between individuals

• Person• Environment• Body weight• Acclimated/Fitness

level

Performance & Hydration

• Performance has been shown to decrease secondary to dehydration– Physically– Mentally

• Decreases start to happen when there is a decrease in total body water of 2%

Performance & Hydration

• People do not perceive the feeling of being thirsty until there is a decrease in total body water of 3%

When things go wrong…

• Sweat response becomes dysfunctional resulting in – An increase in body

temperature– An electrolyte

imbalance

Electrolyte Imbalance

• Levels too high or too low can cause – Arrhythmias– Seizure– Brain damage

Hyperthermia

• Increase in body temperature can lead to– Heat Stroke– Heat Exhaustion– Heat Cramps

Heat Stroke

• Defined by– Body temp > 104 F– CNS Dysfunction– Organ Damage

Heat Exhaustion

• Inability to continue exercising

• Brain mediated “safety break”

• Temperature not as high as HS

Heat Cramps

• Painful muscle cramps– calves

• Associated with large amounts of sodium loss

Who’s at risk for heat illness?

• Those who have had it before

• Out of shape/Unacclimatized

• Overweight

• Age

Warning signs

• Change in mental status

• Dizziness

• Difficulty walking

• Vomiting

• Hyperventilation

Confused with Concussion

• Take a temperature

What to do if suspected

• Remove athlete from play!!!!!

• Call EMS• Place athlete in a

shaded area• Ice

– Emersion– Bags on head, neck,

armpits, groin

Quick Aside

• Sickle Cell Trait– Not a heat illness– Crisis triggered by

• Dehydration• Hypoxemia

– NCAA D1 – Screening– Does not disqualify from participation

Prevention

• Go into practice fully hydrated

• Wear light colored, loose fitting clothing

• Exercise during the cooler parts of the day

• Acclimate over time– Start 10-14 days before training camp– Start at 10 minutes– Increase by another 10 minutes every 2 days

Hydration Guidelines

• Drink 16 oz of water or sports drink one hour before exercise

• Drink 4-8 oz every 15-20 minutes of exercise

• Exercising less than an hour, drink water

• Exercising more than an hour, drink a sports drink

» 16 oz is about half a liter

After Exercise Hydration

• Weigh yourself before and after practice– For every 2 lbs lost drink 48 oz

• If your urine is dark – you are not drinking enough

History of Gatorade

• Created by researchers at the University of Florida in 1965– “Gator”-aid

• Legend of the 1967 Orange Bowl win over Georgia Tech

Pickle Juice

• Anecdotally, helps with muscle cramps

• High in sodium

Chocolate Milk

• Post-work out drink• Increase protein

synthesis• Increases muscle

glycogen• 16 oz about 40 min

after work out• Low-fat

References

• Armstrong, LE, et. al, American College of Sports Medicine Position Stand: Exertional heat illness during training and competition., Med Sci Sport Exer. 2007. pgs 556-572

• Sawka, MN, et. al, American College of Sports Medicine Position Stand: Exercise and fluid replacement., Med Sci Sport Exer. 2007. pgs 377-390