Presentation on theme: "Nutrition for Fitness Professionals Chapter 8 Replacing Sweat Loss Chapter 8 Replacing Sweat Loss."— Presentation transcript:
Nutrition for Fitness Professionals Chapter 8 Replacing Sweat Loss Chapter 8 Replacing Sweat Loss
Exercise and Sweat Muscles generate 20 times more heat during exercise – Sweat evaporates and cools the skin This cools the blood – Which cools the core temperature
Body Temperature Normal: 98.6 F (37 Celsius) Cell damage: 106 F (41 Celsius) Cell protein coagulates: 107.6 F (42 Celsius) Do not overheat! Stay hydrated Know your sweat rate and plan ahead
Staying Hydrated Weigh before and after exercise 1 lb loss = 13-16 oz (replace 80-100%) 1 oz = 1 gulp 16 oz = 1 pint Drink chilled and palatable fluids Set an alarm to drink every 15 minutes We get 20-30% of our fluids from food!
Thirst When body fluid is highly concentrated – Sodium concentration Thirst may be unreliable for athletes losing significant amounts of sweat Thirst can be blunted by exercise! We voluntarily replace only 2/3 of sweat loss Stop drinking if stomach is sloshing
Dehydration 1% body weight can be lost before you feel thirsty – 1.5 lbs/3 cups/ 24 oz – Heart must beat 3-4 more times per minute 2% loss = dehydration 3% loss = significantly impaired performance 9-12% loss = possible death
How Much Water is Lost? Depends on – Sport – Body size – Exercise intensity – Clothing – Weather – Acclimatization – Fitness Level
Other Clues? Check color of urine – Dark and scanty = dehydration – Pale yellow = adequate hydration – B vitamins can make urine appear bright yellow Chronic fatigue Lethargy Headaches Dehydration is cumulative
Pre-Exercise Hydration 2-3 ml per lb at least 4 hours prior – 300-400 ml = 10-15 oz Sodium will stimulate thirst and help fluid retention Don’t over hydrate Can lead to hyponatremia (low sodium) Too many bathroom trips Caffeine – less than 200 mg won’t affect hydration status
Hydrating During Exercise 110-170 mg sodium per 8 oz 20-50 mg potassium per 8 oz 12-24 g CHO (5-10% sugar solution) – 50-95 kals Pretzels and bananas are similar! Exercising longer than 1 hour – 120-240 kcals CHO will enhance performance
Post Exercise Hydration Sipping is better than gulping May take 24-48 hours to fully replenish water Drinking 50% more than lost will enhance recovery See P. 154 for a good sports beverage – What do you go for? Do you need a sports drink?
Other Beverages OJ – great with breakfast – watch kcals Soda – ok, but watch sugar and caffeine – Phosphoric acid/caffeine affects calcium in body Water – get a filter at home – Bottled water does not help environment Energy drinks – avoid! (Sugar and caffeine) Green tea – ok, but watch label abusers Alcohol – avoid! Not good for the body.
Limit Alcohol Alcohol impairs exercise! – Metabolized as fat calories – Men: 2 drinks or less per day – Women: 1 or less per day – Can you save up?
Not necessary unless past 60 minutes 6-8 % solutions Avoid alcohol SPORTS DRINKS