10.25.13 Kin 110 class notes- Critical window?o Recent evidence that consuming more PRO post-exercise causes MORE protein synthesis more muscle growth (maybe)o Also evidence that PRO high in greater PRO synthesis (whey). For example: whey vs. casein Good evidence Whey contains more leucine Leucine causes synthesis?- If you just give leucine it doesn’t work- CSI Amhersto Case study Distance swimmer Flew to middle east for competition Came to a tragic end All swimmers crossed finish line except amer. Swimmer 400 m from the finish Fran Crippen –- 26 yrs old- 19 yrs competitive swimming- competitor it was hot- air temp: 100 degrees farenheit- water temp: 85 degrees (very warm)- few ways to cool body:o radiation, heat coming off bodyo evaporation, sweatingo conduction, heat exchange when air/water in contact with body- Exercise?o How does cooling process affect hydration- Body fluids help regulate temperatureo 98.6o sweating releases heat. Evaporation of water cools skino temp. of core remains stable- sweat evaporates and cools skin- in sedentary people, most fluid losses are as urineo water lost through respiration but its minoro in active people, majority of water loss is sweat- sweat losses are high in hot weathero athletes don’t adapt by sweating they actually sweat moreo why? This is because it controls body temp – helps keep the body coolero trade off between water loss and core tempo more import. To stay cool than to lose fluidso maintain core temp- sedentary person loses ½ L/day in sweato during exercise, sweat 1-2.5 L per hour depending on the temp & humidity (17 oz)o Hot & dry = lose a lot of water in sweat- Replacing water losses is critical. Signs of dehydration at about 2% loss of body watero > 4% potentially, heat exhaustion, “stroke”o running performance vs. % dehydrationo more dehydrated = worse performance- is cooling dif. in swimmers?o Which mechanism? Evaportation Conduction People rarely overheat when swimming- Was Fran the only one?- Fran’s sistero Former Olympic swimmero He wasn’t unprepared for this- Michael sabalao Trained with himo Said he would use somewhere between 10 -15 packs of GU during typical 2 hour swim- Whats in GU?o Caffeineo 350 mg – 525 mg caffeine total (10-15 packs)o this is about 3-4 16 oz coffees (not a crazy amount)o did caffeine play a role?- Caffeineo Increases use of fatty acids for energyo Raises body temp (a bit)o Lowers production of ADH (antidiuretic hormone – conserves water) Cause u to lose more watero Stimulate – raises body temp slightly, sim. To alcoholo May play a role in heat exhaustion- What brough Fran to his end?o Caffeine over dose? Noo Dehydration? Possiblyo Heat exhaustion? Possiblyo Fluid balance Sweating Replenishing fluid- Fluid replacement during exercise?o During hard exercise, difficult to completely replace fluid losseso Recommend replacingo If losing 2 L water/hr, goal to drink 1 L/hour- Replace water losses before dehydrated (seriously)o How?o Pre-exercise = start out with adequate fluido Fluid intake adequate in 24 hours before exerciseo Adequate?- Color of urine indicates level of hydrationo Target: very light coloro Dark: too dehydrated- Intermittent exercise (rest periods), easier to replace fluid losseso Example: tennis, football, baseball/softball etc.o Sports that aren’t intermittent: soccer, lacrosse, hockey- How do you know if you’re hydrated?o Track fluid intake and drink enough to match estimated losseso Tools: waterbottle that keeps track of how much you are consuming- Body weight:o Pre and posto Drink pint of fluid for each pound o Water only nutrient that needs replacing? What about electrolytes?- Is it possible to drink too much
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