Sports Performance – Water, Food Supplements and Performance Enhancing Drugs Learning Objectives: 1. To understand the importance of hydration and electrolytic balance for sports performance. 2. To know what makes sports drinks effective.

Water – vital for the body because:  It regulates body temperature.  It carries nutrients and oxygen to all cells in the body via blood plasma.  Helps convert food into energy and absorb nutrients.  It is required for expiration.  It removes waste.  It protects and cushions vital organs.

Electrolytes  The scientific term for the salts in the body (e.g. sodium, potassium, chlorine)  Vital for the functioning of cells (esp muscle cells). Involved in the transmission of nerve impulses.  Ensure that nutrients and waste products are exchanged.  Maintain the body’s pH level.  Electrolytes dissolve in water and are therefore closely linked with water and sports performance.

Dehydration & Electrolyte Loss  Water and electrolytes are lost during exercise through sweating (due to increased body temp).  Water is also lost during exercise due to increased exhaling (due to increased breathing rate).  Levels lost are effected by temperature, humidity, altitude, and the amount of exercise.  Water loss is greater in cold (as air inhaled is dry), at altitude, or in hot (increased sweating), or in high humidity (sweat does not evaporate and the body cannot cool).

Problems of Dehydration  Water loss causes thickening of blood (reduces blood flow, increases HR).  This effects the body’s ability to cool itself (vasodilation becomes difficult).  Rises in core body temp can lead to heat stress, collapse, and death.  Fluid loss above 3-5% of bodyweight reduces aerobic performance, impairs reaction time, affects judgement, concentration and decision making.

Problems of Electrolyte Loss  Caused by sweating (and/or poor diet).  Leads to drowsiness and poor decision making.  Causes muscle weakness and fatigue.  Causes muscle cramps.  Can result in abnormal heart rhythm. As electrolytes are dissolved in water any change to water levels will effect electrolyte levels and so the two are inter-related.

How to maintain hydration and electrolytic balance  Sports drinks?  Considerations for before, during and after exercise/event. Task: Research sports drinks. What claims do they make? What are the vital ingredients that make them more effective than water? What do they recommend for before, during and after exercise? On one or two sides of A4 create an athlete’s guide to hydration and electrolytic balance based on your research. Recommended sites: Also, p48-49 of A2 textbook.

Temperature Regulation  Core body temperature is 37 degrees.  This is constantly monitored and the body reacts quickly to any changes in core temperature.  Changes in core body temp of just 1 or 2 degrees has a huge impact on sports performance (see p47 A2 textbook).

Cooling / Body reaction to rise in core temperature  Heat is lost through radiation, conduction, convection, and evaporation.  Heat is lost through evaporation during sweating.  Heat is lost through radiation and conduction by vasodilation.

Keeping Warm  If core body temp falls below 35 degrees we begin to suffer from hypothermia.  Core body temp drops due to environmental conditions (low temp and high winds).  Also due to fatigue (inability to keep warm through shivering and other body functions).  To maintain core body temperature in cold conditions performers may increase energy intake, and wear warm, windproof clothing).

The Athlete’s Diet There are numerous food supplements available for athletes. However, research generally shows that an athlete can meet all their nutritional needs through a normal balanced diet which includes:  A sufficient level of carbohydrates (with a range of glycaemic index ratings).  Enough fluids to remain hydrated or rehydrate.  A diet balanced comprising (including carbs, protein, minerals, vitamins, water, fat, and fibre) of whole and unprocessed foods.

Optimal Weight and Fat Percentage  A performer’s optimal weight varies greatly depending on the demands of their sport.  Body fat percentage can be measured by BMI, bioelectrical impedance, or skin callipers.  Body fat percentage can be manipulated by changing energy input (eating) or energy output (training).

Food Supplements and Performance Enhancing Drugs  Research your topic.  Condense the information down to just a few key bullet points.  Write your key bullet points on A3 paper and present your findings to the rest of the group.

Topics:  Creatine  Protein supplements  Herbal Remedies  Caffeine  Bicarbonate of Soda  Erythropoetin  Anabolic Steroids – Testosterone  Human Growth Hormone  Beta Blockers  Diuretics  Stimulants

Extended Learning Task  Review notes on water, food supplements and drugs and complete the revision questions on p60 of A2 textbook.