Sweat Loss. Hydration. Stats. Functions WATER. Water and Sport Drinks

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1 Hydration Water and Sport Drinks Sweat Loss whatever the environmental conditions, sweat losses are probably greater than many athletes appreciate. highest reported sweat rate is 3.7 litres/hour for Alberto Salazar during the 1984 Olympic marathon. sweat rates of 2 to 3 litres/hour can be expected during short periods of hard exercise in the heat litres/hour during endurance events. cooler conditions losses are still appreciable. ex. football game on a cool day (10 deg. C) ex. 2 L of sweat, runners 1.2 L/hr at 6 min/mile pace -(double this amount on a hot, humid day). Stats increase 1!/5 min of exercise sweat loss in 1.5 L to 2.5 L per hr thirsty at 2% water loss - impairs endurance see handout NOTE: exercise suppresses thirst FactSweat.asp Functions WATER 50-60% of body mass Functions: transport nutrients in blood given shape to cells conducts heat to surface lubricates joints and other surfaces digests food water disposal

2 Heat is lost by.. 1) Dilation of capillaries in skin increased blood flow bring heat to skin 2) Sweating water covers the skin heat from body evaporates sweat NOTE: high humidity reduces the ability to sweat, and improper clothing increases sweating Extreme Heat Heat Cramps muscles spasm or tightening due to fluid loss Heat Exhaustion water loss weakens body s ability to regulate temp symptoms - high temp, pale, cool, clammy skin, light headedness, possible loss of consciousness Heatstroke complete failure to regulate heat symptoms - very high body temp, headache, confusion or behavioural change, loss of consciousness Sport Drinks Why are they needed? 1. Water loss recall the importance of water.

3 Why are they needed? 2. electrolytes lost Na, K, Ca, Mg, Cl, HCO 3 1-, PO 4 3-, SO 4 2- A litre of sweat typically contains 0.02g Ca, 0.05g Mg, 1.15g Na, 0.23g K and 1.48g Cl. required for: - essential minerals - control osmosis of water - help maintain the ph balance Hyponatremia condition in which the body s stores of sodium are too low - ex. ironman 3. Carbohydrates lost During hard exercise, - storage up to 2 hrs (at rest 3 hrs) glycogen storage 1,520 to 2,020 kcal. carbohydrate depleted at 3-4 g/min, 10 cal/hr hours for complete recovery of glycogen stores in muscle and liver What about Water? a poor choice where high fluid intake is required. causes bloating, suppresses thirst and thus further drinking. stimulates urine output and therefore is inefficiently retained. Water contains no carbohydrate or electrolytes. In endurance sports, other pts 1) athletes WILL dehydrate, (they can t consume enough) but shouldn t have TOO much 2) CHO depletion is a factor in early fatigue, but if sweat rates are high and dehydration is rapid, then fluid replacement takes priority over CHO. CHO not only delays fatigue but also helps maintain mental alertness and judgement. Recall also the concept ENERGY BALANCE Urine Test The sample should be held up in front of a white background, in good light, and the color compared to the chart to the left. The lower the number, the better the result. A urine color rating of 1, 2 or 3 is considered to be wellhydrated (Armstrong, 2000).

4 Types of Sport Drinks Isotonic fluid, electrolytes (10-25 mmol/litre sodium), and 6-8% carbs absorbs water faster, and adds carbs - electrolytes and CHO are actively absorbed, which creates an osmolarity gradient and increase water intake use: team sports, running, bodybuilding Make you own 6% drink 1 litre water 5 tbps sugar 1/3 tps salt Hypotonic fluids, electrolytes and a low level of CHO (! low calories) get fluid without the carbs uses: gymnasts, jockeys Hypertonic high level of CHO (liquid/gel/solid form) get carb replacement uses: ultra marathons, post exercise Glycemic Index Types of CHO fructose: MS, ex. syrup, slow absorption, good pre meal, galactose: MS, slow absorption glucose: MS, quick absorption and metabolism (Gatorade) sucrose: DS-glucose+fructose, high GI Rules of Hydration 1) ounces of fluid BEFORE exercise The rate of passage of water from your stomach into your small intestine depends on how much fluid is actually in your stomach. If there is lots of water there, fluid flow from stomach to intestine is like a springtime flood; if there is little water, the movement resembles a lightly dripping tap. Therefore, to increase stomach-intestinal flow (and overall absorption of water) you need to deposit a fair amount of liquid in your stomach just before you begin your exercise. 2) 3-4 sips every 10 mins or 5-6 swallows / 15 mins helps maintain flow of water 3) CHO only if over min

5 4) 4-8 % CHO 5)Complex CHO molecules are not required 6) Cold drinks aren't absorbed into your body more quickly but more palatable, and cools body 7) Don t worry about drinking too much on the other hand.. Drinking sports drinks will elevate blood glucose, and this in turn tends to halt the secretion of hgh. perhaps, if hgh is integral to maximizing adaptation to training, taking sports drinks routinely will not result in the best adaptation. other Thirst Mechanism because you are ~ 2% dehydrated at thirst Gatorade increases the Na level to increase thirst quicker, therefore intake more (more $?) Glycerol assists in water retention, though problems can occur with hyper-hydration Energy Drinks Energy vs Sport Drinks 50% higher CHO stimulants (caffeine or guarana) herbs and amino acids ex. Red Bull Energy Drink Ingredients: carbonated water, sucrose, glucose, sodium citrate, taurine, glucuronolactone, caffeine, inositol, niacin, D-pantothenol, pyridoxine HCL, vitamin B12, artificial flavours, colors Nutrition Facts: Serving Size: 8.3 fl. oz Servings per Container: 1 Amount per serving: Calories: 110 Total Fat: 0g Sodium: 200mg Protein: 0g Total Carbohydrates: 28g Sugars: 27g Liz Applegate, a sports nutritionist at the University of California at Davis.... Applegate maintains the boost comes mainly from caffeine. And that, she says makes energy drinks a bad idea for athletes. "Even though they're labeled 'energy drinks,' they should not be consumed during exercise," she said. "They have caffeine, and they're too concentrated in sugar. That's going to slow the body's ability to absorb water."

6 Water Strategies Drink Before exercise oz - 15 min before (don t be thirsty) hrs before competitions Frequently 1/2 to 3/4 cup every min being thirsty is too late Cool Liquids cools body, better absorbed, Sport Drinks only after 90 min or hot weather Sports Drinks or Salt if for more than 6 hours Quench more than thirst Train yourself to drink properly Traveling dehydrates Adjust to hot climates by arriving early Avoid drinks over 10% CHO; fructose: caffeine Recovery articleid=297&level=2&topic=17

7 KEY POINTS continue exercising for minutes at progressively lower intensities to speed the removal of lactic acid from the muscles and blood; stretching of all major muscle groups should follow this activity. begin consuming fluids and carbohydrate immediately after exercise to help the body replace fluids lost in sweat and to replenish muscle glycogen stores. 70 kg (154 lb) athlete should consume grams of carbohydrate ( calories) within the first two hours following exercise to optimize the replacement of muscle glycogen stores. as little as six grams of protein (more is not better) may accelerate protein synthesis in the muscles following exercise. Expensive protein powders and amino-acid supplements are no more effective than normal foods (e.g., meat, fish, eggs) at providing the necessary amino acids. replace both water and electrolytes (especially sodium) during and following exercise to minimize dehydration, to stabilize blood volume, avoid muscle cramps. athletes generally require at least 7-8 hours of sleep each night to perform at their best. Some studies have suggested that consuming protein with CHO during exercise improves endurance performance while other studies have reported no benefits. Additional research will resolve this debate, but it should be remembered that there is no established mechanism by which protein intake during exercise should improve performance. Recent evidence indicates that when CHO is consumed in sufficient amounts during exercise, adding protein provides no performance benefit and does not enhance muscle glycogen synthesis following exercise. Consuming a small amount (10-20 grams) of highquality protein after exercise promotes muscle protein synthesis compared to CHO alone and may enhance the body s response to long-term training.