Water and the bodys electrolyte balance http www

Water and the body’s electrolyte balance http: //www. youtube. com/watch? v=Wz. B-s. Pj 9 u. OQ

Role of Water…. • 50 -60% of adults body mass is water • Regulates body temperature • Carries nutrients and oxygen to all cells in body • • via blood plasma Helps convert food into energy and absorbs nutrients Needed for expiration Removes waste Protects and cushions vital organs

Most basic but vital part of our diet. • Learning Objectives; 1. Role that water plays in 2. 3. maintenance of body functions Effects of dehydration When/how fluids should be taken

Electrolytes • Vital for functioning of cells/ essential minerals • Nutrients and waste products are exchange • They control osmosis of water between body compartments • They help maintain the acid-base balance required for normal cellular activities (p. H is maintained)

• Sodium • Potassium • Chlorine (negatively charged) • Main but others include magnesium, calcium • Needed for electrical impulses of nerve • • transmission Dissolved in water Deficiency in one can alter performance.

How we lose Electrolytes • The sweat that evaporates from the skin contains a variety of electrolytes. The electrolyte composition of sweat is variable but comprises of the following components: • A litre of sweat typically contains 0. 02 g Calcium, 0. 05 g Magnesium, 1. 15 g Sodium, 0. 23 g Potassium and 1. 48 g Chloride. This composition will vary from person to person.

Lose water through • Expulsion of waste products! • Exhaling • Sweating • This depends on humidity, temperature, altitude and type of exercise

How do we lose it? • ¼-1/3 litre lost a day • Most water loss; cold temperatures, altitude- dry air • AND- high temperatures…sweating • Hot and humid conditions do not let sweat evaporate so body can not cool itself.

What happens if we don’t maintina the correct water and electrolyte balance? • Blood thickens/increase in viscosity • Increase in heart rate/heart has to work harder • Reduction in blood flow to working muscles/less oxygen to the muscles • Blood flow to skin reduces/increase in body temperature/heat stroke/unable to maintain correct body temperature • Slows reaction time/decision making/slows nerve impulses • Muscle fatigue • Muscle cramps • Irregular heart beat • Disruption to removal of waste products/lactic acid build up

Electrolyte Balance • Proportion or concentration of electrolytes within the fluid of the body. • Why should we drink water with • electrolytes in?

• Water on its own causes bloating • Intake electrolytes and carbs • Carbs make it more palatable • And add energy value

How much? Prior to Event • • • 400 -600 ml fluid 2 -3 hours before 350 ml just before Eat carbohydrate meal 2 -4 hours prior During the Event • Ingest water and carbs as much as possible even if not thirsty • How convenient is it to hydrate? • Lower GI absorbed more quickly – slow release.

After the Event • • • Rarely able to keep themselves hydrated Tend to underestimate level of hydration Limited opportunities to intake fluid Intolerance to in taking too much fluid Underestimate how much sweating • Must consume high carb meal post event

Effects of dehydration on performance • 2% impaired performance • 4% capacity of muscles to work is reduced • %% Heat exhaustion • 7% hallucinations • 10% Circulatory collapse and Heat Stroke

Exam Question What are the effects of dehydration on an athlete and how does this affect performance? (4 marks)

What are the effects of dehydration on an athlete and how does this affect performance? (4 marks) • • Increase blood viscosity Reduced blood pressure Reduced cardiac output Reduced sweating to prevent water loss Increased core temperature Enzymes become denatured and do not perform to optimum Unable to meet demands of exercise Decreased performance

Outline the physiological changes that will occur if the correct water and electrolyte balance is not maintained. (7)