1. 1 Hydration Dehydration & Hyponatremia

2. 2 Dehydration What is dehydration? How can it be measured?

3. 3 Dehydration Dehydration = Loss of body weight How much loss is a problem?

4. 4 Dehydration = Loss of Body Weight 1% - Medical Definition of Dehydration 2% - 20% drop in Physical Performance 4% - Risk of Heat Exhaustion

5. 5 Dehydration Contributes to: Fatigue Decreased work capacity Lack of Endurance Poor recovery from Exercise Weight loss Depression Apathy

6. 6 Dehydration Contributes to (con’t) Lack of Cold Tolerance –Increased susceptibility to Hypothermia Lack of Heat Tolerance –Increased susceptibility to Heat Illness Discouragement Aggravates Shock Altitude Illness

7. 7 Dehydration contributes to (con’t) Heat Cramps –May play role in development of muscle cramps

8. 8 Dehydration in Cold Environment Low humidity –greater moisture transport without as much sweat. Cold Diuresis –One urinates more often

9. 9 Hyponatremia What is Hyponatremia?

10. 10 Hyponatremia Hyponatremia means low sodium concentration in the Blood. –Too little sodium –Too much fluid (water intoxication) –You can be dehydrated and Hyponatremic!

11. 11 Hyponatremia Sweat can contain as much as 90mEq/liter of Sodium Gatorade contains only 10mEq/liter

12. 12 Hyponatremia Prevention Are you Hungry or Thirsty? Eat salty foods - Junk food is good. Drink fluid to replace sweat loss - no more. People don’t eat when they are hot. People don’t eat when dehydrated and sick. Need 35mEq/liter Sodium to replace sweat.