Staying Hydrated and Energized! Sports Nutrition PIE November 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 water Water essential to digestion and delivery of energy Water 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 Guidelines 3 –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/after Match fluid intake to fluid output Do not rely on thirst as indicator Check urine color

Fluid Replacement Beverages Rapidly absorbed Tastes good No gastro problems Water – less than 60 minutes Sports 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 performance Both are diuretic Alcohol: –Increases urine = water loss –Depresses CNS: Affects balance and coordination Early fatigue due to reduced glucose output –Doesn’t contribute to glycogen Caffeine: –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 electrolytes Need extra when: –Ultra endurance in extreme heat –Using plain water in ultra endurance Variety in diet ensures adequate electrolytes Don’t need sodium tablets

Sources The Ultimate Sports Nutrition Handbook, Coleman and Steen Gatorade Sports Nutrition Conference, 1999 Sports Nutrition Guidebook, Clark Invest In Yourself, Florida NET Sports Nutrition, Missouri NET Coaches Corner, Gatorade Sports Science Institute