Nutrition. Physiology. Israel. Physiology: Nutrition: Ayelet Weinstein, R.D. Itzik Weinstein, Ph.D.

Transcription

1 Fluid Balance Nutrition Physiology Ayelet Weinstein, R.D. Sports Medicine Center The Wingate Institute Israel Itzik Weinstein, Ph.D. Ohalo Academic College Tel-Hai Academic College Physiology: Fluid Balance, Heat, Sweating Dehydration Acclimatization Hyponatremia Nutrition: Re-Hydration: Water, Sport Drinks Recommendations

2 Muscles Components: Water 75% Ward & Lieber. J. Biomechan. 38(11): , 2005 Fluids & Electrolytes Balance Input Output Balance: Output = Input

3 Fluid (H 2 O) Balance Water: Milieu for chemical reactions (The Universal Solvent) Blood volume CV function Body Fluid Compartments: ECV, ICV Fluid Balance Physical Activity 15 X EE (80% Heat!!) Heat Dissipation: Fluid Loss Insufficient Drinking: Fluid Loss Thirst Quantity of Fluid Loss Input Output Input Output

4 Rate of Fluid Loss (Sweating) Environmental: Temp, RH, wind Rowing (Kayak, Canoeing ) On Water In Water 33 C, 80% RH, Slow wind Rate of Fluid Loss (Sweating) Environmental: Temp, RH, wind Clothing & Equipment Genetics Physical Fitness Acclimatization Gender Age

5 Pros Clothing Dry clothing heat exchange (> wet) Cottons & linens absorb H 2 O Loose fitting clothing Light (white) colored clothing (Radiation) Coolmax, Hydroweave TM, etc. Clothing Cons Seal off up to 50% body s surface area from the benefits of evaporative cooling Extra weight heat stress

6 Children (compared to Grownups) Sweat rate Surface / Volume T skin & T core Cardiac Output Mechanical Economy Longer to acclimatize Na + (sweat) Women (compared to men) # Sweat glands Sweat rate Similar tolerance to heat (@ similar %Fat and fitness level)

7 Fluid Input: Avenues ml/day Fluids 50% Fluids 80% Sedentary Active Fluid Loss: Avenues ml/day Sweat 80% Urine 50% Sedentary Active

8 Why Sweat? Dissipate Access Heat Cost: Energy Fluid Salt (NaCl) Blood to skin ( to muscles) Conduction Radiation Convection Heat Transfer Heat = Energy (Kcal, KJoule) High Low

9 Optimal Environmental Temperature 60 min Cycle Ergometer Time Trial Backx et al. 2002

10 Rate of Sweat Rate: Exercise Sawka & Pandolf, 1990 Temp., Exercise Intensity & Fluid Intake ( C) Low RH Nelson et al. 1943; Greenleaf 1994

11 Dehydration Fluid loss % body mass Example: Initial weight: 70 kg 2% loss: 68.4 kg 5% loss: 66.5 kg Effect of Dehydration % Body Mass Work Capacity GI Function Neurologic Function 2 % 4 % 5 % 6 % X Coyle. J Sport Sci. 22: 2004

12 Effect of Dehydration % Body Mass Work Capacity GI Function Neurologic Function 2 % 4 % 5 % 6 % X Coyle. J Sport Sci. 22: 2004 Effect of Dehydration % Body Mass Work Capacity GI Function Neurologic Function 2 % 4 % 5 % 6 % X Coyle. J Sport Sci. 22: 2004

13 Dehydration: GI Function Dehydration Hyperthermia Damage to Digestive System (Micro Villi of GI Epithelial Cells) Lambert. Exerc. Sport Sci. Rev., 32 (4): , Hyperthermia GI Epithelial Cells Normal Heat Stressed 1 Heat Stressed 2 Tummy Aches Diarrhea / Bleeding Lambert et al. JAP. 92: , 2002

14 Dehydration: Symptoms Performance General Fatigue Tummy Aches, constipation GI Absorption Nausea: Female > Males Thirst, severe dehydration vomiting General discomfort: headaches, Dizziness, Confusion Heat sensation in head or neck, Chills How not to finish a race!! 2006 Chicago Marathon Dehydration: Performance Muscle strength Speed Stamina Energy Muscle Exercise Cognitive Process Risk of Injury 95% of muscle cramps dehydration!

15 Dehydration: Symptoms Performance General Fatigue Tummy Aches, constipation GI Absorption Nausea: Female > Males Thirst, severe dehydration vomiting General discomfort: headaches, Dizziness, Confusion Heat sensation in head or neck, Chills Dehydration Summary Cardiovascular function Thermoregulation Injury prevention Performance Recovery

16 How to minimize Heat Stress and Access Fluid Loss Acclimatization to the Heat (Acclimation) Adapt to exercise in the heat Training Camps + Competitions!!

17 Heat Acclimatization (Acclimation) Duration: d Train 1-2 h (same envirn. conditions as the Event ) Cooler environ: Wear additional clothing during training to maintain heat acclim. Hydration during heat-acclim. Acclimatization How? 1 h exercise, 5 d, > 30 C Some athletes: 5-10 d, 2-4 h exerc. Intensive exercise more effective than distance training intensity (60-70%) first days Exposure to hot + dry (w/o exerc) - partial acclim. 1936

18 Acclimatization Body Temp. Acclimatization Body Temp. HR

19 CV Benefits of Acclimatization Plasma Volume (3-27%) BP, stroke volume, sweating capacity given exerc intensity Heat Capacity PV: hormonal changes (ADH + renin), plasma proteins Skin blood flow (more to muscles) Acclim: Sweating Response Sweating capacity (1.5 to 4.0 L/d) Even sweat distribution [NaCl] of sweat Sweat glands sensitivity How? Sweating Threshold Heat Transfer (loss)

20 Acclim. Metabolic Anaerobic - Aerobic (50-60%) reliance on glycogen 8% Performance Lorenzo et al. Appl Physiol 109: , 2010 Physiologic Responses to Acclim. (10-14 d) Physiologic Variable Heart rate Stroke volume T core T skin Sweat output/rate Onset of sweat Sweat Evaporation Following Acclimatization Earlier in training 40

21 Acclim cont d Physiologic Variable Sweat Salt Work output Subjective discomfort RPE Fatigue Work Capacity Mental disturbance ECF volume Plasma volume After Acclim 41 Electrolytes Balance Na + Cl - K + Ca ++ Mg ++

22 Electrolytes Balance: Sweat Na Reabsorption meq/l (Plasma 140) Sweat rate Absorption rate Acclimat. Absorption rate Daily Na Loss 5-6 g GP Bates & VS Miller. J Occup Med Toxicol. 3:4, 2008 Fluid Electrolytes Balance Intake Loss TBW Hyponatremia Excretion H 2 O access Na Content Na Consumption

23 Hyponatremia Normal Na Hyponatremia Fluid /electrolyte disorder: Na <135 meq/l Headache, malaise, confusion, swollen hands and feet, wheezy breathing Seizures, Coma, even death Mechanism: Sweating Na loss in sweat H 2 O drinking around/during events Replacing sweat losses with only H 2 O Intentional Urine Dilution (before drug testing)

24 Hyponatremia and Women Are Women more susceptible than men? Females are more diligent drinkers Female athletes follows (>men) professional advice (exceed?) from coaches, experts Estrogen excess H 2 O loss (central mechanism)? 2007 Chicago Marathon

25 2007 Chicago Marathon

26 2007 Chicago Marathon 7 October 2007 (32 C; 86% RH at 10 am) Race was stopped at 3 ½ h mark 250+ runners hospitalized for heat related ailments Water stations ran out of water early Very limited sports drinks

27 Fluid Replacement Ayelet Weinstein, R.D. The Wingate Institute Nutrition Health Health Performance

28 Some Facts of Life Nutrition Performance Good Nutrition: Poor athlete Top athlete Bad Nutrition Performance Top athlete Nutrition Integral Component of Training Fluid Balance Balanced Nutrition Fluid Replacement Exercise & Recovery

29 Fluid Replacement Voluntary Drinking: 30-70% of Fluid loss What Determines Drinking Volume? Individual habits Availability & Opportunity Palatability (Taste, Temp., Side Effects ) 4-24 h Fluid Balance Fluid Replacement Training of Drinking Habits: Prevents chronic Hypohydration Accurate Planning of competitions

30 Fluid Replacement Personal bottle (school, work, training, competitions) Scheduled hourly drinking Drink temp: Cool drinking Fluid Replacement Cool Water Tastes better body temperature (Hot Environ.)

31 Fluid Replacement Personal bottle (school, work ) Scheduled hourly drinking Drink temp: Cool drinking Taste, sweetness (personal) drinking Fluid Replacement Personal bottle (school, work ) Scheduled hourly drinking Drink temp: Cool drinking Taste, sweetness (personal) drinking Urine Color: Indicator Hydrated De-hydrated Seriously De-hydrated

32 Recommendations Quantity around exercise Before 2 h: 500 ml 5-10 min: ml During Every min: ml After 750 ml fluid for every 1 kg lost ACSM Position Stand, 2009 Fluid Replacement Know (record) your rate of fluid loss (1 lit = 1 kg): Weigh yourself before and after Change drinking habits accordingly Keep practicing drinking competitions

33 Example: Sweat Loss and Fluid! 2 h workout Pre weight 60 kg Post weight 58.5 kg Fluid Intake: 1 L water / sports drink 1.5 L fluid lost + 1L consumed = 2.5 L = sweat loss During exercise: 1.5 L fluid: 200 ml, every 15 min After exercise: 750 ml Fluid Replacement Water or Sport Drinks?

34 Sport Drinks (Isotonic) Water, CHO, electrolytes History of CHO-Elecrolyte Drinks (Gatorade) Florida Gators drank CHO + electrolytes drink and won the game against Atlanta s Georgia Tech Cade & Rich 1965

35 Gastric Emptying Gastric Exec Heart burn Nausea Vomitting Collings et al. MSSE 35: 2003 Gastric Emptying % CHO

36 Fluid Absorption During Exercise Secretion Absorption ± ± Isotonic water ± Hypertonic

37 CHO Content- Sport Drinks Complex CHO: Starch, Maltodextrin Simple CHO: Glucose, Fructose, Sucrose ( sugar ) Absorption Glucose Rapid & utilization by muscle Fructose/ Sucrose Medium Maltodextrin Slow Sport Drinks Water, CHO, Electrolytes Replacement During Exercise Provide water Provide dilute CHO 4-8% (ACSM 2009) Gatorade: Gl+Su+Mx 6% Powerade: Fr+Gl+Mx 8% Fruit juice: Fr+Su 11-15% Soft drinks: Su+Gl 11%

38 Sport Drinks Electrolytes during exercise Replace Na and Cl lost in sweat Water uptake Gatorade: Na, Cl, K, P (460mg/L) Powerade: Na, Cl (300 mg/l) Orange Juice: Na, K (10 mg/l) Soft drinks: Na (40 mg/l) Sport (Isotonic) Drinks Recommended for: Endurance athletes (>1 h) Extreme hot / humid conditions Having troubles Drinking Enough Heavy sweaters Non-Acclimated Improve Energy status

39 How about Energy Drinks Red Bull Forbes et al. Int J Sports Nutr Exc. Metab. 17: , 2007 Energy Drinks 3 sets of WAnT, 2 min rest Forbes et al. Int J Sports Nutr Exc. Metab. 17: , 2007

40 How about Sport Drinks Caffeine 195 mg/l Carnitine 45 mg/l Taurine 1.92 g/l B 3,6,12 Vit. 10% RDA Powerade 7% CHO N=14 Placebo Sport Drink Gatorade Sport Drink ++ Ganio et al. Int J Sports Nutr Exc. Metab , 2010 SPORTS DRINKS Are they really for you? Convenient & Portable Energy: Pre, during & post exercise Refill glycogen stores after exercise Taste personal... Trial & Error

41 Homemade Sport Drink Ingredients 4 Tsp sugar 1/4 tsp salt 50 ml orange juice 50 ml hot water 2 Tsp lemon juice 700 ml cold water dissolve sugar, salt in hot water, add juice & cold water, chill 200 ml servings: 50 Kcal, 12g CHO, 110 mgna, 30mgK Nancy Clark s Sport Nutrition Guidebook, 2 nd ed Homemade Sport Drink Ingredients 1/4 tsp salt 500 ml fruit juice (not flavored) 500 ml cold water Dissolve juice, salt & cold water 200 ml serving: 40 Kcal, 10g CHO, 110 mg Na, 30mg K AW Personal

42 Summary Fluids Q.T.Q. Quantity Timing Quality

43 The Individual The Choice is all Yours

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