Staying Hydrated and Energized!

Sports Nutrition PIENovember 6-8, 2001

By Susan Mills-Gray, Nutrition Specialist

What’s the Big Deal about Water?

Distribution of water in the body:– 65% intracellular – 35% extracellular

70-75% of muscle mass is made of waterWater essential to digestion and delivery of energyWater as sweat acts as a coolant to prevent body temperature overheating

Important to keep balanced

The Road to Dehyrdration

The most common cause of fatigue Occurs from sweat loss:– Contributes to fatigue– Increases risk of developing heat illness

Body temperature rises as byproduct of working muscles

The Road to Dehydration

Large losses thru sweat impair performance– Blood usually used to transfer oxygen to muscle

diverted to skin to reduce heat– Competition for blood between muscle & skin puts

greater demand on cardiovascular system– Blood volume reduced due to sweat loss

Sweat first comes from extracelluar, then intra :– Mostly from muscle and skin –protects brain/organs

The Road to Dehydration

Body is programmed to protect cardiovascular function at expense of body temperature regulation– Skin blood flow + sweat rate reduces body fluid =

• Raised body temp = dehydration

As little as 2% body weight loss may impair performance

Effect of Dehydration On Performance

10%9%8%7%6%5%4%3%2%

2% 3% 4-6% >6%

Fluid Replacement Guidelines3– 3 hours before 2-3

cups

2– 2 hours before 2 cups

1– 1 hour before 1-2 cups

Time Out!– Time out for fluids

• ½ cup every 15 minutes

2 cups of fluid for every pound lost

Fluid Replacement Guidelines

Weigh before/afterMatch fluid intake to fluid outputDo not rely on thirst as indicatorCheck urine color

Fluid Replacement Beverages

Rapidly absorbedTastes goodNo gastro problemsWater – less than 60 minutesSports drink – longer than 60 minutes

Fluid Replacement Tips

Sports drinks:– Contain carbs and sodium

• Glucose + sodium increases fluid & carb uptake in gut– Need to be 6 to 8% carbs– Higher than 8% carbs (sodas, fruit juices, some sports drinks)

• Takes longer to be absorbed• Abdominal cramps• Nausea• Bloating• Diarrhea

– Allows athlete to retain water without inhibiting thirst

Alcohol and Caffeine

Both impair performanceBoth are diureticAlcohol:– Increases urine = water loss– Depresses CNS:

• Affects balance and coordination• Early fatigue due to reduced glucose output

– Doesn’t contribute to glycogenCaffeine:– Carbonation takes up space– Increases blood pressure and heart rate

Electrolytes

Sodium, chloride, potassium– Responsible for:

• Body fluid levels• Muscle contractions• Nerve impluse

transmission

Sweat costs electrolytes– Especially sodium

Water loss concentrates electrolytesNeed extra when:– Ultra endurance in extreme

heat– Using plain water in ultra

endurance

Variety in diet ensures adequate electrolytesDon’t need sodium tablets

Sources

The Ultimate Sports Nutrition Handbook, Coleman and SteenGatorade Sports Nutrition Conference, 1999Sports Nutrition Guidebook, ClarkInvest In Yourself, Florida NETSports Nutrition, Missouri NETCoaches Corner, Gatorade Sports Science Institute